Gear up kit for Buddy 50 Confirmed!! 70mph Runner

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Ohh buddy
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Gear up kit for Buddy 50 Confirmed!! 70mph Runner

Post by Ohh buddy »

Just wondering if anybody found any gear up kits that fits and works for the buddy 50? I've searched and seems there is only kits available just recently for the 125 150 and 170i. I plan on getting a 70cc kit (probably water cooled) with a few other go fast goodies. My goal is 60mph or more GPS and that should be easily attainable being its a two stroke but I need to gear up the final drive so the engine won't spin a million rpms for engine life.(I'm not going to get started on the stock crankshaft ect ect, I'll get to that topic later on) I'm not plan on maintaining those high speeds. Basically I would like it to be fast and reliable. I could get a bigger bike but I want to see what these two strokes are all about since I read about and seen so many videos of horizontal minarelli 2t running 60-70+mph with wheelie standing acceleration!!
Last edited by Ohh buddy on Wed Aug 19, 2015 9:54 pm, edited 10 times in total.
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Post by Jonny D »

Brohammer. Let me know how that goes. I am not aware of any final drive step up kits however, the cylinder kit and variator kit should do the trick for 50-55 but, 60 and up I feel is maxoblow-y-upy on the crank sooo.... yea... just my thought. :evil:

I only realy say this cause Im doing the same Jazz currently... not liquid cooled though. going cheap. :twisted:
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Post by Ohh buddy »

yeah I'm not sure how well these cranks hold up on power and rpms. Its already spining 7900rpms@40mph I last recalled
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Post by skully93 »

Given that the 150's hit that, and only just under the right conditions, why not spend half the $$ and get the machine that's built for it?

(not judgin', just sayin')
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Post by Ohh buddy »

That would be very nice.. I want to get my hands on a buddy 170i or hooligan. I know both of those bikes can do 60-70 off the show room floor .. but I really like 2t. Plus I bought this bike for a seal.
TVB

Post by TVB »

Ohh buddy wrote:Plus I bought this bike for a seal.
I don't think most states will allow a seal to operate a motorbike of any kind on public roads.
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Post by Ohh buddy »

TVB wrote:
Ohh buddy wrote:Plus I bought this bike for a seal.
I don't think most states will allow a seal to operate a motorbike of any kind on public roads.

Sorry, I met steal. I bought the bike from a private owner that needed to sell it quickly
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Post by skully93 »

Oh, well if you already have it...

I'm not sure about the trans kits. If you can save up the scratch, maybe some more experienced techs can tell you what needs to go into the 70cc kit and setup.
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Post by Ohh buddy »

skully93 wrote:Oh, well if you already have it...

I'm not sure about the trans kits. If you can save up the scratch, maybe some more experienced techs can tell you what needs to go into the 70cc kit and setup.
I read about project Frenchy on this forum about the buddy 50 with a 70 kit, pipe, carb and cvt tuning. Just with those mods, they were able to get up to 46mph in just a 1/8 mile. So that should give me a good starting point. But as of now, I know that the buddy 50 I have has i gear ratio of 11.5:1. I have a spare gear set from a gy6 50 that I will see if it will press fit and work and fit within the buddy's gear housing. If it does, then ill have a nice selection of gears and ill report my info back here.
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Post by lovemysan »

There is very little information available regarding up gears available for the buddy 50. The rattler 50 and 110 gears will interchange to my knowledge. There was a guy in taiwan running a business called samarai scoot or something that like. He very briefly imported up gear kits and bbk's for the rattler 110 4-5 years ago. If you dig around the zuma forums look for user name smellybumlove. I think mike kojima at motoiq built a rattler 110 as well.
161cc big bore kit, NCY big valve head Hand ported, NCY transmission kit, jetted and tuned. I can port your cylinder head.
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Post by Ohh buddy »

lovemysan wrote:There is very little information available regarding up gears available for the buddy 50. The rattler 50 and 110 gears will interchange to my knowledge. There was a guy in taiwan running a business called samarai scoot or something that like. He very briefly imported up gear kits and bbk's for the rattler 110 4-5 years ago. If you dig around the zuma forums look for user name smellybumlove. I think mike kojima at motoiq built a rattler 110 as well.
Speaking of the rattler 110. I was digging around on the rattler forum and found someone had a installed a gear up kit that barely fit and mentioned had to machine its diameter of both gears 0.5mm. This person also mentioned the stock rattler 110 gears were 13/43 or 10.13:1 the taller one was for the Yamaha Aerox 50 Polini Uprated Secondary Gear Kit which have different ratios available. Since you mention that the 50 and 110 rattler final drive gears are interchangeable with the Buddy 50, I may have just solved my gear up problem.
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Post by lovemysan »

SIP had some pgo up gear kits but they are nla now.
161cc big bore kit, NCY big valve head Hand ported, NCY transmission kit, jetted and tuned. I can port your cylinder head.
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Post by Ohh buddy »

lovemysan wrote:SIP had some pgo up gear kits but they are nla now.
Thanks! I keep my eyes on that...but if I can't get a gear up kit I'll guess I'll find the Rattler 110 gears and swap those in since they are 10.13:1 ive read.
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gear up kits for buddy 50??

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As an update I know it's been a while but I found something interesting. To make a long story short and I'll try to keep it as short as possible if i can..but I've recently purchased a 1e50qmf/jog 90 long case minarelli engine sometime ago.. The gear ratio of the jog 90 long case is 10.1:1 and the Buddy 50 gears are 11.5:1 but yesterday I decided to try to swap gears from the jog engine into the buddy 50 but the 90 gears were a little bit too big kinda hard to explain but, I decided to try the buddy 50 gears into the jog 90 and they fit perfect I was able to rotate the clutch shaft with ease. So i closely examined both gears from looks of them they may be able to be pressed off/on the shafts and swapped without any issues so I may have solve my gear up problem. The only thing I may only have to do is find gears for this type of engine but this is unconfirmed at the moment.. I will definitely post back here when I can confirm itImage
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Gear up kit for Buddy 50 Comfirmed!!

Post by Ohh buddy »

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I just installed a Polini secondary 15/42 that I orderd from sip.. Everything went smoothly. I used a 12 tons shop press and had very little issue with the impressing in.. after the installment, I bolted up the gear cover and everything fits perfect I have no binding or grinding whatsoever from the gears when spinning the wheel by hand. The gear ratio is now 9.5:1 from the stock 11.5
If anyone interested:
"Polini Secondary p2021346" (15/42 for 9.5:1 final drive ratio)
OR
"Polini Secondary p2021321" (14/41 for 9.9:1 final drive ratio)
Last edited by Ohh buddy on Fri Jun 26, 2015 11:09 pm, edited 1 time in total.
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Post by Syd »

Interesting thread! Keep us posted (pun intended) on the improvements in top end / if it affects acceleration.

Well done.
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Post by babblefish »

Very interesting work you're doing ohh buddy. Yes, please keep us up to date on what effects the gear change does for you.

I was thinking about doing the exact same thing with the transmission gears in my Blur 150. There are a lot of gear sets available for generic GY6 engines/transmissions, but none of them look like what PGO uses in the Blur. Thought I wouldn't be able to use any of them until I realized that the gears are pressed on. So, as soon as I get a chance, I'll be pulling my gears out to have a look see if generic gears and PGO gears are compatible. BTW: the gears in a 50cc Buddy are different than those in the 150/170cc Buddy/Blur.
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Gear up kit for Buddy 50 Confirmed!!

Post by Ohh buddy »

Sure thing! I will give an update on how these gears perform with my current setup. [/b]
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Post by lovemysan »

I performed several gear swaps with a large vice, fire, and a freezer. I did a cam gear as well. The cam was more difficult.
161cc big bore kit, NCY big valve head Hand ported, NCY transmission kit, jetted and tuned. I can port your cylinder head.
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Post by Ohh buddy »

lovemysan wrote:I performed several gear swaps with a large vice, fire, and a freezer. I did a cam gear as well. The cam was more difficult.
you were able to press on the cam gear without it bending?
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Post by Ohh buddy »

I have to say the 9.5 are not to bad for my set-up on my buddy But I think I should have opted for the 9.9 which I think that's better for this set-up but, I'm planning on upgrading it with more power so the 9.5 are staying. Now for the good news. Im 145lb and I was wearing lightweight clothing and tires set at 40psi at the time I measured my speed. My max speed is 55mph gps when i am tucked on a flat road with out any wind or help from any vehicles that's in front of me. As far as off the line take off I have to give it a little more throttle from a dead stop but I'm not really complaining even though the 11.5 had way better take off enough to wheelie off the line when I yank the throttle wide open. But once I get moving, I really dont even feel like I have these 9.5's I haven't lost any nor gain acceleration while cruising at a certain speed when i yank the throttle wide open. The engine speed is not screaming like they were with the oem gears at 50mph which should increase engine life. Also these gears are straight cut from Polini which run quiet and I really thought there were going to be whiny. Not sure if anybody notice or if it's just me but the original buddy 50 gears were a little whiny at speeds.
Now for the bad news which isn't much. When taking off from a dead stop I'm having issues with belt slippage being that the gears are taller requires more effort to get the bike moving from a standstill but I think I can solve that by going with a stiffer contra spring mostly then adjusting the sliders. Now I have said my top speed is 55 tucked, sitting straight up I'm only able to get up to 50mph gps at WOT but the engine speed is much lower. With the old gears top speed with the same conditions and road was 48mph gps sitting upright, 50mph tucked with the engine speeds way too high. At the moment the engine does not have enough power to push me past 50 sitting up but soon that's going to change.. Also I forgot to mention at 55mph on the gps the speedo reads 60-61 bmph not sure what everybody else is reads?
Last edited by Ohh buddy on Sun Jun 28, 2015 2:56 pm, edited 1 time in total.
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Post by Ohh buddy »

This is my current setup at the moment:
-Malossi sport 70cc dual-ring cast iron air-cooled 12:1 compression ratio(93 octane fuel)
-Malossi carbon reeds pedals
-Prima PGO race tuned pipe
-StylePro PGO racing intake manifold
-OKO 18.5mm D-slide Carb 90mj
-NGK bpr8hs
-Ncy Super Trans: lightened variator (extended ramps for more belt travel), lightened torque driver pulley (adjustable angle), lightened clutch bell and clutch shoes
-Ncy 1k clutch springs
-Dr.Pulley 15x12, 7G sliders
-Klotz BēNOL Racing Castor Oil
-Polini Secondary 15/42 9.5:1 Final Drive
Other notes: 145lb 5'11" rider, Bore&Stroke 47x39.2=68cc, 40psi tire pressure on stock 90/90-10, running stock oil injector with permix fuel, at or below sea level
Last edited by Ohh buddy on Mon Jun 29, 2015 5:29 pm, edited 2 times in total.
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Post by az_slynch »

Have you seen this pipe for your Buddy 50? The moped tuners have been developing sidebleed expansion chambers in recent years with good gains. Might be worth a look for your tuning.

http://www.treatland.tv/MLM-genuine-bud ... pe-495.htm
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Post by babblefish »

Sounds like you're making some great headway there. Be careful of your tire pressures though, you're 10lbs over what is recommended by Genuine and I suspect, the tire manufacturer.
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Post by k1dude »

babblefish wrote:Sounds like you're making some great headway there. Be careful of your tire pressures though, you're 10lbs over what is recommended by Genuine and I suspect, the tire manufacturer.
I just had a dealer change my rear tire. After a quick jaunt making sure it was balanced properly, I checked the pressure. My gauge only goes up to 60 psi and it was pegged! I bled air out of the tire for what seemed like forever. I suspect they inflated it to 80 psi or more! One problem is there was no inflation range recommendations on the tire. Odd.
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Post by Ohh buddy »

az_slynch wrote:Have you seen this pipe for your Buddy 50? The moped tuners have been developing sidebleed expansion chambers in recent years with good gains. Might be worth a look for your tuning.

http://www.treatland.tv/MLM-genuine-bud ... pe-495.htm
I've seen that pipe on other scooters and mopeds
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Post by Ohh buddy »

babblefish wrote:Sounds like you're making some great headway there. Be careful of your tire pressures though, you're 10lbs over what is recommended by Genuine and I suspect, the tire manufacturer.
Mehh, I'm not too worried about that I really need higher speed rated tires. I really would like to go a bit taller in the front only to slow down the speedometer a bit
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Post by Ohh buddy »

I had did a top speed run last night. Going one way my phone gps clocked me at 52mph then on my why back home it read 57 and I was sitting mostly up right the whole time i was riding. I know the winds were calm and my riding is on a flat road but i did modify my stock air box before i headed out.
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Post by Ohh buddy »

Finally! I have reach my 60mph goal! (65bmph)This was done on a flat road no wind or any cars that was in front of me. But i had to really tuck level or just barely enough to just over the headlight. Anyone wanna race? Its just a 70cc, no big deal, right?

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Post by az_slynch »

Well done! :clap:

Do you have any mapped acceleration curves? I'd be curious as to how you Buddy pulls from a stop to top speed.

I used to use Google's My Tracks to figure out top speed and to map speed/distance curves. Was helpful in tuning the variator's on mopeds in order to avoid dips in the acceleration curve and keep the engine at optimal power from clutch engagement to top speed.
At what point does a hobby become an addiction? I'm uncertain, but after the twelfth scooter, it sorta feels like the latter...

Seriously...I've lost count...

Seven mopeds ...that's still manageable...
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Post by Ohh buddy »

az_slynch wrote:Well done! :clap:

Do you have any mapped acceleration curves? I'd be curious as to how you Buddy pulls from a stop to top speed.

I used to use Google's My Tracks to figure out top speed and to map speed/distance curves. Was helpful in tuning the variator's on mopeds in order to avoid dips in the acceleration curve and keep the engine at optimal power from clutch engagement to top speed.
Hey, Thanks! I Dont have any mapped acceleration curves.. Before I installed the 9.5 gears and had the oem 11.5 While the CVT was tuned to the best of my ability with the ncy super trans kit that I had purchased from scooterworks the most important pieces in the kit were the variator with the extended ramps for more belt travel for increase top speed and the secondary sliding sleave for the rear/driven pulley with adjustable angle which keeps the engine at a constant rpm unlike the stock pulley half which the angle dog legs which drops the RPM for cruising, mpg and engine life. But other than that, It was able to pull the front wheel about maybe 3-4ft off the ground from a dead stop, it almost flipped on me once or twice. It has lots of low end torque. From a stop to top speed there's no hesitation and keeps pulling until its reaches it's drag limit max speed. Now with the 9.5's if I sit about halfway to the rear of the seat, it just barely lift the weight off the front wheel but now I'm getting belt slippage because of the taller gears but I can fix that. But even still with the gear up kit I haven't noticed any acceleration loss while rolling and maybe just a little less take off from a dead stop but to me its really not that noticeable.
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Post by Ohh buddy »

I have an update for anyone wondering how much speed and power you can get out of a Genuine/PGO 2-stroker well here's whats new/changed and modded:
Old: Malossi sport 70cc iron dual-ring 47mm bore 68cc, exhaust port raised 5mm for more upper rpm power, NGK BPR8HS, Prima Race pipe, 7g sliders unmodded, Ncy 1k contra spring, max speed Full Tucked -60.4mph or 97.2km/h-

New: Stage6 Sport Pro 70cc Mk2 aluminum cylinder nikasil plated bore, single-ring 47.6mm bore 69.75cc, NGK BR9HS gap to 0.57mm, Yasuni c16, Dr.Pulley 7g sliders cut down to weigh 5g each, ncy 1k contra, NCY high tension coil, airbox modded again for more flow.
I had to removed some material from the cylinder head combustion chamber to reduce compression ratio from 14:1 because of detonation.
Everything else has not been touched. Im even still spinning the stock crank with the 10mm pin and possibly pushing the limits of the stock crank but power difference between my old setup and the new setup is a BIG difference.. I can not believe how much more power it makes now. BUT, I do not recommend this for around town stop and go traffic. It has very little bottom end power and I do not recommend this setup for anyone that has that type of travel and this setup configuration is clearly aimed towards speed and power only ;)
Last edited by Ohh buddy on Wed Aug 19, 2015 9:50 pm, edited 2 times in total.
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Post by Ohh buddy »

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Post by Ohh buddy »

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Malossi 47mm piston on left Stage6 47.6mm on right
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The speedometer was reading 74-75bmph

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Last edited by Ohh buddy on Wed Aug 19, 2015 9:44 pm, edited 1 time in total.
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Post by Ohh buddy »

Max rpms Full Tucked at 70mph without any help from cars, tail wind or a down hill slope.

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Cool!

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I have really enjoyed your posts! They have been both interesting and enlightening!
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Re: Cool!

Post by Ohh buddy »

Clydeo wrote:I have really enjoyed your posts! They have been both interesting and enlightening!
That's great I'm glad you found this really interesting, thanks for the interest ;) I have really enjoyed tuning my scoot. The money, time, and labor that I have put into it was well worth it. There are some things that I haven't mentioned like this exhaust system requires removal of the center kickstand because of the shorter header pipe design, and relocating the stock air box because of the intake and carb, and dealing with a bit of slack in the throttle cable. Plus, I have to fill up the oil tank more often because of the increase rpms which causes it to pump more oil and adding a little bit of oil into the fuel tank with increase fuel comsumption. It's all part of tuning/modding.. but I'm perfectly fine with that. I don't ride it on a daily basis if i do it will be mostly just for fun :) the good thing about it is I can put everything back to stock. But I'm not done with it yet
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Post by jickel »

Great thread, it's good to see people seriously modding these things! I've just been getting started tuning my buddy 50, and like any vehicle, mods & hp are addicting.

What made you switch from the Prima race pipe to the Yasuni pipe? The need for higher 9k+ rpms? I've just swapped on an Athena 70cc kit and I've been offered a Prima race pipe for only 40.00 bucks which is tempting, but I want it to be ideal for my currently mild setup.

I'll probably take the stage 6 head path like you did eventually, but I just want to get to 55+ indicated with my current head.
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Post by Ohh buddy »

jickel wrote:Great thread, it's good to see people seriously modding these things! I've just been getting started tuning my buddy 50, and like any vehicle, mods & hp are addicting.

What made you switch from the Prima race pipe to the Yasuni pipe? The need for higher 9k+ rpms? I've just swapped on an Athena 70cc kit and I've been offered a Prima race pipe for only 40.00 bucks which is tempting, but I want it to be ideal for my currently mild setup.

I'll probably take the stage 6 head path like you did eventually, but I just want to get to 55+ indicated with my current head.
I switch from the Prima because I was looking for more power and speed. But it's a good upgrade from the stock pipe once I got the prima tuned properly. I decided to tried the stock exhaust and lost 6mph on top end! But as far as the c16 pipe, i did some reading and searching I came up on a article that was doing an exhaust shootout between different pipes and the Yasuni c16 came out on top with 11hp at the wheels on a water cooled yamaha aerox 70cc. But that wasn't convincing just enough so I went on other forms and others have said this pipe performs incredibly well so after that I decide to buy it once I got it tuned I was literally blown away by the power difference between the prima and c16. But yes, Higher RPM's are needed for the Yasuni c16 pipe.. 9,800-10,300 rpms seems to be the perfect range paired with the Stage 6 sport pro Mk2. I'm still using the ncy 1k torque spring but I've lightened the Dr. Pulley sliders that were originally weighted 7g down to 4.6g.. but if you do go this route you must upgrade the 10mm wrist pin/gudgeon bearing to a stronger one Polini, Stage6 or Malossi and other supporting mods to get the power down to the wheel. Right now I'm running the S6 10mm bearing. but as far as the stock crank its holding up incredibly well I'm still using the stock oil pump with a little bit of oil in the fuel tank. Someone on another forum tested PGO two-stroke cranks can handle 12k-12,7k rpms.. and I do believe this. But just recently I've broke my 70 top speed.. just a day or so ago I got up to 73 that's with a taller rear tire 100/90-10 with a worn belt. You're more than welcome to ask any questions that's on your mind and if you would like the links to these two forums, just feel free to ask me.
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Post by jickel »

Ohh buddy wrote:
jickel wrote:Great thread, it's good to see people seriously modding these things! I've just been getting started tuning my buddy 50, and like any vehicle, mods & hp are addicting.

What made you switch from the Prima race pipe to the Yasuni pipe? The need for higher 9k+ rpms? I've just swapped on an Athena 70cc kit and I've been offered a Prima race pipe for only 40.00 bucks which is tempting, but I want it to be ideal for my currently mild setup.

I'll probably take the stage 6 head path like you did eventually, but I just want to get to 55+ indicated with my current head.
I switch from the Prima because I was looking for more power and speed. But it's a good upgrade from the stock pipe once I got the prima tuned properly. I decided to tried the stock exhaust and lost 6mph on top end! But as far as the c16 pipe, i did some reading and searching I came up on a article that was doing an exhaust shootout between different pipes and the Yasuni c16 came out on top with 11hp at the wheels on a water cooled yamaha aerox 70cc. But that wasn't convincing just enough so I went on other forms and others have said this pipe performs incredibly well so after that I decide to buy it once I got it tuned I was literally blown away by the power difference between the prima and c16. But yes, Higher RPM's are needed for the Yasuni c16 pipe.. 9,800-10,300 rpms seems to be the perfect range paired with the Stage 6 sport pro Mk2. I'm still using the ncy 1k torque spring but I've lightened the Dr. Pulley sliders that were originally weighted 7g down to 4.6g.. but if you do go this route you must upgrade the 10mm wrist pin/gudgeon bearing to a stronger one Polini, Stage6 or Malossi and other supporting mods to get the power down to the wheel. Right now I'm running the S6 10mm bearing. but as far as the stock crank its holding up incredibly well I'm still using the stock oil pump with a little bit of oil in the fuel tank. Someone on another forum tested PGO two-stroke cranks can handle 12k-12,7k rpms.. and I do believe this. But just recently I've broke my 70 top speed.. just a day or so ago I got up to 73 that's with a taller rear tire 100/90-10 with a worn belt. You're more than welcome to ask any questions that's on your mind and if you would like the links to these two forums, just feel free to ask me.

This is great, thanks a ton for the info. I finally ditched my Athena head + Prima pipe, and installed the S6 MK2 head and upgraded S6 10mm oversize bearings + Yasuni C16 pipe. This thing rips! More buddy 50 people need to explore the aftermarket beyond the Prima stuff. I went with a 19mm Dellorto carb and a 98 main jet with the airbox baffle pipe removed for now. I need to do some a/f tuning on it just to make sure I'm not running too lean.

Do you think 5g sliders are safe still running a 10mm setup? I really don't feel like going the 12mm route anytime soon.

Maybe one day I'll tackle the gearing upgrade like you did, but for now I'm enjoying my 0-60 mph blasts. I need to find a Grom to line up with :)
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Ohh buddy
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Post by Ohh buddy »

jickel wrote:
Ohh buddy wrote:
jickel wrote:Great thread, it's good to see people seriously modding these things! I've just been getting started tuning my buddy 50, and like any vehicle, mods & hp are addicting.

What made you switch from the Prima race pipe to the Yasuni pipe? The need for higher 9k+ rpms? I've just swapped on an Athena 70cc kit and I've been offered a Prima race pipe for only 40.00 bucks which is tempting, but I want it to be ideal for my currently mild setup.

I'll probably take the stage 6 head path like you did eventually, but I just want to get to 55+ indicated with my current head.
I switch from the Prima because I was looking for more power and speed. But it's a good upgrade from the stock pipe once I got the prima tuned properly. I decided to tried the stock exhaust and lost 6mph on top end! But as far as the c16 pipe, i did some reading and searching I came up on a article that was doing an exhaust shootout between different pipes and the Yasuni c16 came out on top with 11hp at the wheels on a water cooled yamaha aerox 70cc. But that wasn't convincing just enough so I went on other forms and others have said this pipe performs incredibly well so after that I decide to buy it once I got it tuned I was literally blown away by the power difference between the prima and c16. But yes, Higher RPM's are needed for the Yasuni c16 pipe.. 9,800-10,300 rpms seems to be the perfect range paired with the Stage 6 sport pro Mk2. I'm still using the ncy 1k torque spring but I've lightened the Dr. Pulley sliders that were originally weighted 7g down to 4.6g.. but if you do go this route you must upgrade the 10mm wrist pin/gudgeon bearing to a stronger one Polini, Stage6 or Malossi and other supporting mods to get the power down to the wheel. Right now I'm running the S6 10mm bearing. but as far as the stock crank its holding up incredibly well I'm still using the stock oil pump with a little bit of oil in the fuel tank. Someone on another forum tested PGO two-stroke cranks can handle 12k-12,7k rpms.. and I do believe this. But just recently I've broke my 70 top speed.. just a day or so ago I got up to 73 that's with a taller rear tire 100/90-10 with a worn belt. You're more than welcome to ask any questions that's on your mind and if you would like the links to these two forums, just feel free to ask me.

This is great, thanks a ton for the info. I finally ditched my Athena head + Prima pipe, and installed the S6 MK2 head and upgraded S6 10mm oversize bearings + Yasuni C16 pipe. This thing rips! More buddy 50 people need to explore the aftermarket beyond the Prima stuff. I went with a 19mm Dellorto carb and a 98 main jet with the airbox baffle pipe removed for now. I need to do some a/f tuning on it just to make sure I'm not running too lean.

Do you think 5g sliders are safe still running a 10mm setup? I really don't feel like going the 12mm route anytime soon.

Maybe one day I'll tackle the gearing upgrade like you did, but for now I'm enjoying my 0-60 mph blasts. I need to find a Grom to line up with :)
Those five gram sliders should be good but you really need to get a tachometer to monitor your rpms. 10,200rpms seems to be ideal I noticed after playing with the weights and rpms. But you do not want to exceed 10,5rpms. I have noticed that the power curve starts to fall off after 10,5rpms so that's really no point going above that anyway ..but I have to spin the crank at 11k rpms (give or take) just to reach 70+mph. but my new top speed is 73mph gps. I'm running a 100/90-10 rear tire but still using the worn out stock belt. if I install a new belt I should be flirting with 75 or if not more thats if I have enough power.

Unfortunately, I'm having trouble with premature wrist pin bearing failure (sounds like a bunch of coins being shook in a glass jar) from excessive rpms. But the bottom end of the crank is fine just that 10mm wrist pin starts complaining of those high rpms and once it starts it keeps rattling. I think that's why there are crank upgrade from the stock crankshaft to a 12mm WP that would fit most minarelli scoots.

Also, you should also listen for spark knocking. Where I live I have not so great gas. This S6SP compression ratio is a high 14:1. I was getting severe detonation so I had to open up the combustion chamber inside the head a lot to lower the compression. I've eliminated most of the detonation but it still present at a certain RPM. Right now it's 190psi cranking compression thats still a little too high for pump gas. But this kit was intended for racing and required race fuel.

But my other trouble solving is spark plug fouling. The stock ignition system isn't up to the task with the power and rpms. I've literally have to close the plug gap down to .5mm to try to reduce spark blowout. I'm running an NCY high tension coil which actually did help a little bit not enough. I am running a little rich at WOT but I'm doing it to keep it cool and to help reduce a little spark knock. But in return getting fouled plugs.

After doing some more searching I may have found an upgraded full circle crankshaft for PGO 2T made by BGM. The only problem is still retains the 10mm wrist pin. I also came across that Polini sells a conrod thats 80mm in length (supposably PGO 50cc 2t conrods are exactly this length) with the 12mm pin. But I have to pull the crank and have the machine shop remove the old rod so i can check measurements. I'm also considering an Malossi inner rotor kit that will help with replace the weak ignition system to increase spark voltage and throttle response. It might just work for these engines I'm almost certain it will work just have to sacrifice charging and lighting :(
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Ohh buddy
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Gear up kit for Buddy 50 Confirmed!! "70mph Runner"

Post by Ohh buddy »

jickel wrote:
Ohh buddy wrote:
jickel wrote:Great thread, it's good to see people seriously modding these things! I've just been getting started tuning my buddy 50, and like any vehicle, mods & hp are addicting.

What made you switch from the Prima race pipe to the Yasuni pipe? The need for higher 9k+ rpms? I've just swapped on an Athena 70cc kit and I've been offered a Prima race pipe for only 40.00 bucks which is tempting, but I want it to be ideal for my currently mild setup.

I'll probably take the stage 6 head path like you did eventually, but I just want to get to 55+ indicated with my current head.
I switch from the Prima because I was looking for more power and speed. But it's a good upgrade from the stock pipe once I got the prima tuned properly. I decided to tried the stock exhaust and lost 6mph on top end! But as far as the c16 pipe, i did some reading and searching I came up on a article that was doing an exhaust shootout between different pipes and the Yasuni c16 came out on top with 11hp at the wheels on a water cooled yamaha aerox 70cc. But that wasn't convincing just enough so I went on other forms and others have said this pipe performs incredibly well so after that I decide to buy it once I got it tuned I was literally blown away by the power difference between the prima and c16. But yes, Higher RPM's are needed for the Yasuni c16 pipe.. 9,800-10,300 rpms seems to be the perfect range paired with the Stage 6 sport pro Mk2. I'm still using the ncy 1k torque spring but I've lightened the Dr. Pulley sliders that were originally weighted 7g down to 4.6g.. but if you do go this route you must upgrade the 10mm wrist pin/gudgeon bearing to a stronger one Polini, Stage6 or Malossi and other supporting mods to get the power down to the wheel. Right now I'm running the S6 10mm bearing. but as far as the stock crank its holding up incredibly well I'm still using the stock oil pump with a little bit of oil in the fuel tank. Someone on another forum tested PGO two-stroke cranks can handle 12k-12,7k rpms.. and I do believe this. But just recently I've broke my 70 top speed.. just a day or so ago I got up to 73 that's with a taller rear tire 100/90-10 with a worn belt. You're more than welcome to ask any questions that's on your mind and if you would like the links to these two forums, just feel free to ask me.

This is great, thanks a ton for the info. I finally ditched my Athena head + Prima pipe, and installed the S6 MK2 head and upgraded S6 10mm oversize bearings + Yasuni C16 pipe. This thing rips! More buddy 50 people need to explore the aftermarket beyond the Prima stuff. I went with a 19mm Dellorto carb and a 98 main jet with the airbox baffle pipe removed for now. I need to do some a/f tuning on it just to make sure I'm not running too lean.

Do you think 5g sliders are safe still running a 10mm setup? I really don't feel like going the 12mm route anytime soon.

Maybe one day I'll tackle the gearing upgrade like you did, but for now I'm enjoying my 0-60 mph blasts. I need to find a Grom to line up with :)
this is my current setup as of this post not much has changed:
-Stage6 Sport Pro Mk2 70cc (10mm piston pin) single ring aluminum cylinder Nikasil plated Bore air-cooled (not ported) combustion chamber opened to reduce compression ratio from 14.1 Cranking compression ~190psi..Bore&Stroke 47.6x39.2=69.7cc (on stock crank and oil pump)
-Malossi carbon reeds pedals 
-Yasuni C16 tuned pipe
-StylePro PGO intake manifold
-OKO 18.5mm D-slide Carb 90mj/40sj 
-NGK br9hs (one step cooler)
-Ncy Super Trans: lightened variator (extended ramps for more belt travel), lightened torque driver pulley (adjustable angle), lightened clutch bell and clutch shoes
-Stage6 hard red clutch springs
-Ncy high tension coil (stock cdi, stator, and flywheel)
-Polini Secondary 15/42 gears (9.5:1)
-Dr.Pulley 15x12, 7G sliders (weight reduce to weigh 4.8g each)
-Maxima Castor 927 Pro Series racing 2t oil
-Stock modified air box
-Taller rear tire 100/90-10 (previous 90/90-10)
- Reduce little weight by removing unnecessary things: stock exhaust (much heavier & restrictive than the Yasuni c16 because of catalyst) center stand, rear fender, rear rack, oil tank cover, access cover under seat, stock cylinder was cast iron now replaced with the S6 aluminum.. all of this adds up probably weighs about 12 pounds less now the last time I weighed all the stuff I took off with a scale and compensate from the replacement of the exhaust, cylinder and other things.
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Post by jickel »

Ohh buddy wrote:
jickel wrote:
Ohh buddy wrote: I switch from the Prima because I was looking for more power and speed. But it's a good upgrade from the stock pipe once I got the prima tuned properly. I decided to tried the stock exhaust and lost 6mph on top end! But as far as the c16 pipe, i did some reading and searching I came up on a article that was doing an exhaust shootout between different pipes and the Yasuni c16 came out on top with 11hp at the wheels on a water cooled yamaha aerox 70cc. But that wasn't convincing just enough so I went on other forms and others have said this pipe performs incredibly well so after that I decide to buy it once I got it tuned I was literally blown away by the power difference between the prima and c16. But yes, Higher RPM's are needed for the Yasuni c16 pipe.. 9,800-10,300 rpms seems to be the perfect range paired with the Stage 6 sport pro Mk2. I'm still using the ncy 1k torque spring but I've lightened the Dr. Pulley sliders that were originally weighted 7g down to 4.6g.. but if you do go this route you must upgrade the 10mm wrist pin/gudgeon bearing to a stronger one Polini, Stage6 or Malossi and other supporting mods to get the power down to the wheel. Right now I'm running the S6 10mm bearing. but as far as the stock crank its holding up incredibly well I'm still using the stock oil pump with a little bit of oil in the fuel tank. Someone on another forum tested PGO two-stroke cranks can handle 12k-12,7k rpms.. and I do believe this. But just recently I've broke my 70 top speed.. just a day or so ago I got up to 73 that's with a taller rear tire 100/90-10 with a worn belt. You're more than welcome to ask any questions that's on your mind and if you would like the links to these two forums, just feel free to ask me.

This is great, thanks a ton for the info. I finally ditched my Athena head + Prima pipe, and installed the S6 MK2 head and upgraded S6 10mm oversize bearings + Yasuni C16 pipe. This thing rips! More buddy 50 people need to explore the aftermarket beyond the Prima stuff. I went with a 19mm Dellorto carb and a 98 main jet with the airbox baffle pipe removed for now. I need to do some a/f tuning on it just to make sure I'm not running too lean.

Do you think 5g sliders are safe still running a 10mm setup? I really don't feel like going the 12mm route anytime soon.

Maybe one day I'll tackle the gearing upgrade like you did, but for now I'm enjoying my 0-60 mph blasts. I need to find a Grom to line up with :)
Those five gram sliders should be good but you really need to get a tachometer to monitor your rpms. 10,200rpms seems to be ideal I noticed after playing with the weights and rpms. But you do not want to exceed 10,5rpms. I have noticed that the power curve starts to fall off after 10,5rpms so that's really no point going above that anyway ..but I have to spin the crank at 11k rpms (give or take) just to reach 70+mph. but my new top speed is 73mph gps. I'm running a 100/90-10 rear tire but still using the worn out stock belt. if I install a new belt I should be flirting with 75 or if not more thats if I have enough power.

Unfortunately, I'm having trouble with premature wrist pin bearing failure (sounds like a bunch of coins being shook in a glass jar) from excessive rpms. But the bottom end of the crank is fine just that 10mm wrist pin starts complaining of those high rpms and once it starts it keeps rattling. I think that's why there are crank upgrade from the stock crankshaft to a 12mm WP that would fit most minarelli scoots.

Also, you should also listen for spark knocking. Where I live I have not so great gas. This S6SP compression ratio is a high 14:1. I was getting severe detonation so I had to open up the combustion chamber inside the head a lot to lower the compression. I've eliminated most of the detonation but it still present at a certain RPM. Right now it's 190psi cranking compression thats still a little too high for pump gas. But this kit was intended for racing and required race fuel.

But my other trouble solving is spark plug fouling. The stock ignition system isn't up to the task with the power and rpms. I've literally have to close the plug gap down to .5mm to try to reduce spark blowout. I'm running an NCY high tension coil which actually did help a little bit not enough. I am running a little rich at WOT but I'm doing it to keep it cool and to help reduce a little spark knock. But in return getting fouled plugs.

After doing some more searching I may have found an upgraded full circle crankshaft for PGO 2T made by BGM. The only problem is still retains the 10mm wrist pin. I also came across that Polini sells a conrod thats 80mm in length (supposably PGO 50cc 2t conrods are exactly this length) with the 12mm pin. But I have to pull the crank and have the machine shop remove the old rod so i can check measurements. I'm also considering an Malossi inner rotor kit that will help with replace the weak ignition system to increase spark voltage and throttle response. It might just work for these engines I'm almost certain it will work just have to sacrifice charging and lighting :(
Thanks for sharing your ideas/experience. It looks like I'll be trying to find an upgraded crank sooner than later. I was doing some high rpm/mph pulls last night when I think the stock crank decided to call it quits. It's not good when you pull the fan cover to find broken fan blades and can wobble the stator housing around! I'm sure I was spinning the motor too high. I guess the vibrations I was feeling at an indicated 60 mph were either the wrist pin bearing (I'm using the S6 oversized one), or the bottom end. Funny thing is I was just cruising around 45-50 mph when it decided to self destruct. I didn't detect any bad knock with these temps we're getting here this winter, and I'm using a premix of klotz and 93 octane. I had the scoot running great at 12.8:1-13.5:1 a/fs (I was using a rigged AEM Wideband O2 setup for some carb tuning).


I just started my research for a 12mm setup, but it looks like you've been doing a lot more! I was hoping there would be a ton of options like the other minarellis but I guess not.

https://www.scooter-attack.com/shop/en/ ... ution.html

This still uses a 10mm setup but supposedly it's good for 15k. Hmm. I might just go with this since I don't really need to spin my motor past 10,500 like you mentioned. I was planning on ordering a tach this week, but it looks like I'll have a lot more in my shopping cart now lol. Hopefully my head survived the carnage so I can reuse it. Guess I'll go to the garage and inspect that now.

The inner rotor ignition setup sounds interesting...I'll look into it too since my stator and magnetic pickup might have been damaged. Just briefly looking at it just now doesn't show any compatibility with a PGO/Buddy, but who knows for sure.
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Location: Austin, TX

Post by jickel »

I wonder if the crank kits used on Yamaha Zumas will work for us? This would eliminate the oil pump, but we could just premix the old fashioned way anyway.

I'm going to measure my crank, and luckily my friend has a stock Zuma crank laying around that he'll measure and compare.

https://www.scooter-attack.com/shop/en/ ... -12mm.html

He's running this crank now in his Zuma, so if the only thing we lose is the oil pump then I'll order this setup. It's possible we may have to switch to a different variator and bearing setup, but I'm thinking/hoping the shafts are the same length and diameter.
Last edited by jickel on Fri Feb 19, 2016 6:40 pm, edited 1 time in total.
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Ohh buddy
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Post by Ohh buddy »

jickel wrote:I wonder if the crank kits used on Yamaha Zumas will work for us? This would eliminate the oil pump, but we could just premix the old fashioned way anyway.

I'm going to measure my crank, and luckily my friend has a stock Zuma crank laying around that he'll measure and compare.

https://www.scooter-attack.com/shop/en/ ... 6-HPC.html

He's running this crank now in his Zuma, so if the only thing we lose is the oil pump then I'll order this setup. It's possible we may have to switch to a different variator and bearing setup, but I'm thinking/hoping the shafts are the same length and diameter.
If you can wobble the entire right casing with your hand then crankshaft may have flew apart/failed, destroying the engine casing. There is a left and right use crankcase and for the buddy 50 on eBay last time I checked a day or so ago. Spinning the crank at 11K is nerve racking for me. I believe the 10.5k rpms I mentioned earlier is a little on the low side. I'll say maybe 10.8k should be the starting redline for this setup. But, If I had to guess you're probably spinning close to 12k maybe even flirting with 13k rpms If you're still on the stock variator and final drive. To me that's a no no if you're trying for top speed. If you get a gear up kit get the Polini 9.9's. If 70mph top speed is a must 9.5 is what you have to go with. Then you should get the ncy super trans kit which increases belt travel for more top speed and it should help keep your rpms steady. The torque driver has two adjustable angles which also controls rpms at certain speeds. My uploaded video of the ncy variator showing how much the belt travels up the variator for more top speed potential https://youtu.be/rUUkyG5xook

But let me know how that Zuma crank works. I kind of have a feeling the variator ramp plate won't fit. along with the different flywheel taper which may not be interchangeable. but I could be wrong.
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Post by babblefish »

jickel wrote:I wonder if the crank kits used on Yamaha Zumas will work for us? This would eliminate the oil pump, but we could just premix the old fashioned way anyway.

I'm going to measure my crank, and luckily my friend has a stock Zuma crank laying around that he'll measure and compare.

https://www.scooter-attack.com/shop/en/ ... 6-HPC.html

He's running this crank now in his Zuma, so if the only thing we lose is the oil pump then I'll order this setup. It's possible we may have to switch to a different variator and bearing setup, but I'm thinking/hoping the shafts are the same length and diameter.
Dunno, the Buddy and Zuma cranks sure look different, though the bore and stroke are the same:
Attachments
Zuma 50 Crank
Zuma 50 Crank
zuma50cs.jpg (16.34 KiB) Viewed 6064 times
Buddy 50 2T Crank
Buddy 50 2T Crank
bubu50cs.jpg (7.85 KiB) Viewed 6064 times
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jickel
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Post by jickel »

Thanks, hopefully I'll get an answer today regarding the Zuma vs. PGO crank. The crank sheared right at the Stator bell housing so luckily my case and head should be ok.

Image

Image

Image

The cranks do look different, but the main difference that stands out is the oil pump drive on the Buddy crank. I'll be eliminating the oil pump, so it shouldn't be an issue. Fingers crossed!

Before I order the super trans kit I want to make sure the OEM variator will fit...I'm guessing I'll have to go with an upgraded Zuma variator worst case. Might have to ditch the electric start too, but hopefully not. I foresee doing the gear upgrade in the near future as well. Top speed wasn't a goal with this build (just rip your face acceleration :D ) but gears will help on the long frontage road pulls.
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Post by babblefish »

Your ignition timing sensor looks pretty beat up. Might want to check and make sure it's still good. Also, there's a good chance that your crank failed the way it did due to the high RPMs causing a harmonic vibration to occur with the stator flywheel which over time caused the crank to break due to metal fatique. Whatever you do in the future to repair the engine, it would be wise to have the flywheel balanced, dynamically if possible. That's a lot of weight hanging off the end of the crank so any imbalance will be greatly magnified at higher RPMs. For sustained high RPM use though, balancing the flywheel with the crank would be best, but I don't know of any shop who can do this for small engines. Automotive engines, yes.
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