Increase Acceleration - 70cc Kit, Prima Pipe, etc?

mattsyd · Post by **mattsyd** » Wed Jul 08, 2015 5:44 am

I love my Buddy 50, but would like a little more power. I'm not really worried about top speed, any gain in top speed from mods would just be icing on the cake. The top speed, derestricted, on level ground is about 45-48mph (50-52bmph); I was very surprised by this. Even with two people we can get it up to 40mph on a level ground. It does take a good while to get to these speeds, haha, but I usually don't drive on streets that require anything over 35-40.
My main concerns are:
1) More overall acceleration to get the hell out of the way from someone who might run over me.
2) More low end acceleration to get moving when stop lights turn green.
3) More low to mid acceleration/power for when my wife rides with me (although a rare occasion, about once every couple weeks).
4) And, a louder muffler with more distinct sound to help those driving around me know I'm there would be awesome as well.

With all this said, I've been looking at a 70cc Kit and Prima Pipe, this to be exact: http://www.scooterworks.com/performance ... Zy285NViko

What would the be the benefits of this kit?
Would I need to make any mechanical adjustments or buy anything additional to make this work?
What acceleration and power gains would I see (upper/mid/lower-end)?
If I am pretty good at figuring out how to install things like this on my own, but don't have any experience working on scooters/automobiles, do you think it would be reasonable to say I could figure out how to install this kit using youtube videos? (I already know I can install the muffler, its the 70cc kit I am concerned about)

Thanks for the past and future help!
You guys are awesome!

edit:
btw, here's a few reasons why I don't want to get a 125 instead of upgrading my 50.
I don't want me and my wife to have to spend $300 dollars on motorcycle course and license. In Texas you can get a restricted "K" motorcycle license for $20-25 from the DPS if you scooter is under 50cc (I'm assuming a cop is not going to investigate whether or not I have a 70cc kit, again, I'm assuming. Haha.) Cash has just become very limited because we had to get my wife's car worked on,

Buying a 125 and getting two licenses would costs anywhere between $1000-$2500 depending on the luck of finding a good deal. Upgrading my 50 just enough to get us buy until we can afford a 125 (hopefully a new one) would cost $325.

babblefish · Post by **babblefish** » Wed Jul 08, 2015 9:29 am

That kit will give you more power for sure, but I'm pretty sure with that pipe, the increased power will be mostly in the upper mid-range to top-end. Your carburetor will have to be re-jetted for a richer mixture because of the pipe and increased displacement.

Installing the 70cc kit will be very easy as this is a 2-stroke (2T) engine. Here is a check list of things to do/lookout for, when installing the BB kit:

- Be careful when installing the piston rings onto the piston because they are made of cast iron and can break if twisted too much.
- Each piston ring has a top and a bottom. The top should have an engraved mark near the end gap.
- Make sure the piston is installed on the connecting rod the correct way with the ports facing up (toward the intake).
- Lightly oil the piston, rings, and cylinder wall before installing the cylinder barrel. Do NOT use a synthetic oil for this. Use good old dino oil or else the piston rings may not seat/break-in correctly.
- Position the piston rings on the piston so that their gaps are 180 degrees away from each other, in other words, opposite of each other.
- Be very careful when sliding the cylinder barrel over the rings. Squeeze the ring closed into it's piston groove while sliding the barrel in place.
- After you get the engine running, re-torque the head nuts after about 50 miles of riding and then check it again at about 150 miles.

There are a bunch of YouTube videos on how to install one of these BB kits if you want something a bit more visual.

If you're looking for more acceleration and get up and go for two-up riding, some tuning of the transmission will be helpful. Going to a firmer contra-spring (yellow, or 1500 rpm) in the rear pulley will allow the transmission to stay in a lower gear ratio a bit longer to help acceleration. Also, since adding a tuned pipe usually moves the power band up in the rpm range, changing the three springs in the clutch to stiffer replacements (yellow, or 1500 rpm) will allow the engine to rev higher, thereby into it's most efficient power range before the clutch engages.

You might find this YouTube video useful. There are 3 parts and he talks about hopping up a 50cc 2T scooter and tuning the transmission. The author is a bit OCD, but there is a lot of good info in his videos. He's also got other videos explaining variator and engine tuning.

<iframe width="560" height="315" src="https://www.youtube.com/embed/d3cQKYT0ojg" frameborder="0" allowfullscreen></iframe>

sc00ter · Post by **sc00ter** » Wed Jul 08, 2015 3:11 pm

We (wife and I) had a Hyosung Sense 50 that we felt compelled to rescue and use for her to learn on. It was quick de-restricted but we put on a expansion pipe and a aftermarket variator on and it really moved off the line AND top end-even 2 up! No need to rejet the carb and it stayed reliable because we never went into the motor. Its still on the road, years later, running strong with a new owner. I think the pipe (Technigas) was around $160 and the vario (Malossi) was $80. The Buddy 50 aftermarket leans more towards the Prima brand parts, and I have no experience with them.

avescoots1134 · Post by **avescoots1134** » Thu Jul 09, 2015 1:52 pm

I would stay away from the pipe, it takes a whole bunch of tuning to get any bottom end power, not to mention making the kit less reliable by upping the top end power. Slap a kit on with the stock exhaust and rejet and enjoy!

mattsyd · Post by **mattsyd** » Sat Jul 11, 2015 7:37 am

Thanks for the input everyone...
So with the info y'all gave me and other stuff I've read on the forums, I'm leaning towards only doing a 70cc kit and may even just start with a new belt and rollers.

One concern I have with doing any of these mods would be reducing the reliability of the scooter. Right now my Buddy 50 runs flawlessly. And although I wish it had just a little bit more power, I also don't want to have it stall from time to time or make it difficult to start sometimes or have to retune the bike constantly to keep it running properly. With that in mind, what suggestions/advice would y'all have? And do you all think any of these issues would occur if I installed a 70cc kit?

sc00ter · Post by **sc00ter** » Sat Jul 11, 2015 1:05 pm

As a whole if the 70cc kit is set up correct it will be just as reliable as stock. I beat the poo out of the Zuma, running WOT for looong stretches, gunning it from every stop, riding a passenger, being mean to it, and it has been pretty bullet proof-so it can be done. Keep a eye on the plug seat temp for the cylinder and a cheap tach will help in setting everything up (rollers/torque springs/clutch springs) if you go into the transmission.

mattsyd · Post by **mattsyd** » Sun Jul 12, 2015 12:46 pm

So, what do y'all think about this setup:
http://www.scooterworks.com/prima-cylin ... aJgJpNViko
with
http://www.scooterworks.com/ncy-super-t ... aJgVpNViko

From what everyone has said, it seems this will give me a good boost in overall power, give me more acceleration at bottom to mid range (where I want it the most), shouldn't require much tuning, and should keep my Buddy 50 reliable.

And just to clarify, would I need to re-jet? I've gotten conflicting opinions while researching this.

sc00ter · Post by **sc00ter** » Sun Jul 12, 2015 2:45 pm

Rejet=yes. You will actually have to rejet around 2-3 times to get it correct and reliable (stable/safe temps and good moca colored plug end), meaning you will be getting to know the carb insides (pilot/slide/main) very well. If you try to fine tune the transmission (split the torque driver open to replace the torque spring) and the clutch springs-get ready to buy some big sockets and good snap ring pliers-oh, and a torque wrench. Not sure if the Buddy50 uses a clutch tool to hold the fixed sheave on the variator or you'll have to use a strap wrench. Tuning it can get annoying (mainly transmission) but when done and tuned correct it will be worth it.

mattsyd · Post by **mattsyd** » Mon Jul 13, 2015 1:26 am

After I do the transmission kit and switch out the clutch spring/rollers/variator/etc, is tuning it just a matter of switching out the rollers to get a weight thats best for the top-speed/acceleration that I desire? Or is there something else I would need to do to tune the transmission? Also, I'm sure I can get ahold of a pair if I need to, but are the snap ring pliers a necessity to do this project?

sc00ter · Post by **sc00ter** » Mon Jul 13, 2015 3:04 pm

I have found good snap ring pliers can swap out the 3 clutch springs the best. One you find a engagement that works you wont have to do them again. My Zuma is set up for a single rider, but it does ok with my wife on the back. You may not need to change the torque spring, meaning no big socket (from Buggy Parts NW-they have the 2 sided 39/41mm torque driver nut socket). You will have to set up the rollers, to get it balanced for both single rider and passenger. A tuning roller pack is good for this, then order what final weights you need afterwards. I suggest a torque wrench but I know alot of people who dont bother with one, they just scribe the original position of the nut or bolt, so that is your call. Oh, and to hold the fixed drive sheave (to get to the rollers) Im not sure if it has clutch holder holes or if a strap wrench (Home Depot has the best one) is needed. Use a impact driver on the variator nut AT YOUR OWN RISK. I have seen some terrible things happen when impact drivers are used. Again, AT YOUR OWN RISK. Take your time. Watch some tuning videos. Dont be afraid to ask questions. Enjoy a faster scoot!