Buddy 125 variator upgrade *with pictures*

docutech · Post by **docutech** » Sun Sep 21, 2008 2:00 am

Tomorrow I will be installing my new variator with new slider weights and a Polini kevelar belt. Initially, I will be mixing 9 gram and 11 gram weights. We will do some test runs and tweak if needed.

With this upgrade I am hoping to gain some quickness off the line as well as add a few miles to my top end. Stay tuned MB'ers!

A side note:
Are the stock Buddy 125 rollers 9.5grams?

Howardr · Post by **Howardr** » Sun Sep 21, 2008 3:13 am

Take some pictures while your doing the change. It will educational. I'll definately be looking forward to hearing how it affects your performance.

Howard

jfrost2 · Post by **jfrost2** » Sun Sep 21, 2008 4:54 am

You can find an old tutorial for changing the buddy's variator, but there is also one pinned in the tech section for the blur, the instructions are 99% the same for both bikes.

Post by **Lostmycage** » Sun Sep 21, 2008 7:38 am

You might find that a mix of 10g and 11g are perfect with the slider setup. I'll keep a tab on this one as well. I'm just impressed that you actually got what you ordered. Mind sharing who you bought from?

newslinky · Post by **newslinky** » Sun Sep 21, 2008 11:12 am

Also which Buddy are you performing the change on?

Post by **Lostmycage** » Sun Sep 21, 2008 6:17 pm

I'd wager it's the blue one...

dorian · Post by **dorian** » Sun Sep 21, 2008 6:53 pm

I look forward to seeing a graphic tutorial of your experience with the change.

By the way, how does a new variator increase top-end speed unless the original one was faulty? I can se the increase in acceleration due to a change in roller/slider weights, but the top end seems to be fixed as far as variators go. Also, are you going to experiment with the spring on the clutch as well?

docutech wrote:A side note:
Are the stock Buddy 125 rollers 9.5grams?

I believe the stock 125CC Buddy roller weights are 18x14mm, 11.5g.

Shane Wilson · Post by **Shane Wilson** » Sun Sep 21, 2008 8:28 pm

Are you sure the belt is going to work?

I've yet to hear of a successful Kevlar belt replacement on a buddy.

Post by **ericalm** » Sun Sep 21, 2008 8:46 pm

Shane Wilson wrote:Are you sure the belt is going to work?

I've yet to hear of a successful Kevlar belt replacement on a buddy.

The MRP belt doesn't fit, but I think the Pollini does. We shall see!

docutech · Post by **docutech** » Mon Sep 22, 2008 12:48 am

newslinky wrote:Also which Buddy are you performing the change on?

The upgrade was performed on my 08 Buddy 125 Bone stock with 4200 miles on the clock

So, the upgrade is complete. Well… sort of. First of all I want to say how incredibly easy this is to do. By the time I had my camera turned on to take the pictures the mechanic had the cover off and the old variator removed.

jfrost2 wrote:You can find an old tutorial for changing the buddy's variator, but there is also one pinned in the tech section for the blur, the instructions are 99% the same for both bikes.

Agreed, everything in that tutorial is exactly the same.

It is a very good idea to have a impact wrench (electric or pneumatic will work) as this makes it so much easier to remove the 17mm nut that holds the variator in place. So this is what things looked like inside when I got around to snapping the pictures:

With the cover off and the old variator removed you can clearly see the black rubber dust that has accumulated inside. This is from the belt and is perfectly normal.

As planned, 9g and 11g weights were installed in a alternating sequence and the new variator was in place:

The next thing was to replace the belt.

Shane Wilson wrote:Are you sure the belt is going to work?

I've yet to hear of a successful Kevlar belt replacement on a buddy.

Unfortunately the belt did not fit. It was about 2 inches too long.

Bummer, I really didn’t want to go through the hassle of return/exchange. If anyone knows the correct numbers for a kevlar belt I am all ears. FIY Polini 248.060 does not fit.

Here are some shots of the old variator and rollers. Surprisingly, they had no flat spots whatsoever but as you can see from the pictures some of the rollers are thinner than others. I used my food scale and weighed each one only to find that three of the rollers were at 11g, two were at 10g and one was at 9g. I would guess I could have gone another 800 miles to make these last until the 5k mark.

Here is a shot of the old variator. Notice the discolored portion of the right wheel. It is from the belt actually wearing the metal down. Also notice the dark lines near the center as well as near the outer circumference. Those are actual grooves that the belt has cut into the metal.

Once everything was cleaned up and we blew out the variator housing, we buttoned things up and it was ready for the test drive.

dorian wrote: By the way, how does a new variator increase top-end speed unless the original one was faulty? I can se the increase in acceleration due to a change in roller/slider weights, but the top end seems to be fixed as far as variators go.

You were correct by stating the above. There is a drastic improvement in the acceleration with my 9g/11g setup. The initial jump off the line is an absolute thrill! My top end has remained the same. My only concern at the moment is the high engine revs when I take off WOT (wide open throttle). It seems that the engine has to work quite hard for the first 50 feet or so. Once I get going the engine calms down retaining power and speed. It is quite hard to describe. Acceleration from 40mph-55mph has also improved. It is smoother and at speeds above 50mph I do not experience the engine whine as I did before.
Things have gotten a lot quieter as well. The old variator and weights made a lot of noise. This, as I understand, was caused by the rollers having a lot of wear on them thus clunking around in the chambers. The change is very apparent and my scooter sounds a lot better.

dorian wrote: Also, are you going to experiment with the spring on the clutch as well?

Yes, this will be something I look at for a future mod. However, a Prima exhaust pipe will be next on my list. Supposedly, tuning the engine will enable it to produce more power more efficiently. We shall see.

Kaos · Post by **Kaos** » Mon Sep 22, 2008 12:59 am

I actually did this swap today as well. Did you remove the clutch for any perticular reason? As its not a requirement to remove it to swap variators.
I started out going with 10.5g weights, but that really just felt a bit too light compared to the 11g's I had before, so I ended up mixing the 10.5's and the 11's, and we'll see how that goes

docutech · Post by **docutech** » Mon Sep 22, 2008 1:13 am

My mechanic believes in teaching his customers about how things work. He removed the clutch cover to show me the how's and why's. He explained the main spring as well as the smaller ones that are needed to make it go!

Kaos · Post by **Kaos** » Mon Sep 22, 2008 1:15 am

docutech wrote:My mechanic believes in teaching his customers about how things work. He removed the clutch cover to show me the how's and why's. He explained the main spring as well as the smaller ones that are needed to make it go!

Wow, thats slick. I think that customer education is something cool to see from a mechanic!

docutech · Post by **docutech** » Mon Sep 22, 2008 1:22 am

Kaos wrote:
docutech wrote:My mechanic believes in teaching his customers about how things work. He removed the clutch cover to show me the how's and why's. He explained the main spring as well as the smaller ones that are needed to make it go!
Wow, thats slick. I think that customer education is something cool to see from a mechanic!

When I told him that there is a video on Youtube of a 10 year old kid doing a variator upgrade he handed me a cordless drill and said "YOU DO IT" lol
He was serious and also said that if I did it by myself he wouldn't charge me a dime... What a cool dude. I respectfully declined and asked him to do the work. Now I know what to do

Kaos · Post by **Kaos** » Mon Sep 22, 2008 1:23 am

docutech wrote:
Kaos wrote:
docutech wrote:My mechanic believes in teaching his customers about how things work. He removed the clutch cover to show me the how's and why's. He explained the main spring as well as the smaller ones that are needed to make it go!
Wow, thats slick. I think that customer education is something cool to see from a mechanic!
When I told him that there is a video on Youtube of a 10 year old kid doing a variator upgrade he handed me a cordless drill and said "YOU DO IT" lol
He was serious and also said that if I did it by myself he wouldn't charge me a dime... What a cool dude. I respectfully declined and asked him to do the work. Now I know what to do

What weight sliders did you end up going with? And what did you think of performance with them.

docutech · Post by **docutech** » Mon Sep 22, 2008 1:31 am

docutech wrote:There is a drastic improvement in the acceleration with my 9g/11g setup. The initial jump off the line is an absolute thrill! My top end has remained the same. My only concern at the moment is the high engine revs when I take off WOT (wide open throttle). It seems that the engine has to work quite hard for the first 50 feet or so. Once I get going the engine calms down retaining power and speed. It is quite hard to describe. Acceleration from 40mph-55mph has also improved. It is smoother and at speeds above 50mph I do not experience the engine whine as I did before.
Things have gotten a lot quieter as well. The old variator and weights made a lot of noise. This, as I understand, was caused by the rollers having a lot of wear on them thus clunking around in the chambers. The change is very apparent and my scooter sounds a lot better.

armacham · Post by **armacham** » Mon Sep 22, 2008 1:33 am

What ended up being the total cost to do this? Did you get all the parts just from the dealer?

docutech · Post by **docutech** » Mon Sep 22, 2008 1:38 am

OOh , I forgot. I got everything from Scootertronics. I know, I know... they aren't the best folks to deal with but I found out "after" the fact. They had the goods to my door in a timely fashion but as mentioned above the kevlar belt did not fit.

About 250 dollars total, shipped to my door.

Kaos · Post by **Kaos** » Mon Sep 22, 2008 1:41 am

docutech wrote:
docutech wrote:There is a drastic improvement in the acceleration with my 9g/11g setup. The initial jump off the line is an absolute thrill! My top end has remained the same. My only concern at the moment is the high engine revs when I take off WOT (wide open throttle). It seems that the engine has to work quite hard for the first 50 feet or so. Once I get going the engine calms down retaining power and speed. It is quite hard to describe. Acceleration from 40mph-55mph has also improved. It is smoother and at speeds above 50mph I do not experience the engine whine as I did before.
Things have gotten a lot quieter as well. The old variator and weights made a lot of noise. This, as I understand, was caused by the rollers having a lot of wear on them thus clunking around in the chambers. The change is very apparent and my scooter sounds a lot better.

Interesting, thats about the same as my first run(Only down the street and back) It seemed initially to be at much higher RPM than the stock variator, but then it slid(for lack of a better word) into a better power band.

docutech · Post by **docutech** » Mon Sep 22, 2008 1:47 am

That is exactly what I experience too.

Here is me goofing off while my mechanic is hard at work...

armacham · Post by **armacham** » Mon Sep 22, 2008 2:37 am

oh one more question, the buddyies use 18x 14 mm sliders, right? i was thinking of just seeing what slightly lighter weights would do for me. I hardly ever use the top end anyway around town.

docutech · Post by **docutech** » Mon Sep 22, 2008 2:42 am

Yes, they are 18mm x 14mm.

Kaos · Post by **Kaos** » Mon Sep 22, 2008 2:49 am

armacham wrote:oh one more question, the buddyies use 18x 14 mm sliders, right? i was thinking of just seeing what slightly lighter weights would do for me. I hardly ever use the top end anyway around town.

Yeah, they're 18x14, 11g sliders work nicely in the stock variator.

BuddyLicious · Post by **BuddyLicious** » Mon Sep 22, 2008 2:59 am

Hey Kaos & Docutech,

I assume your are using your stock belt? I was just wondering since it seems from reading different threads there isn't a known belt to fit.Also I'm assuming there is not a best weight set up as again I'm reading about different weights being used.So at least some of the weight set up is a personal choice? Lastly do you think there is simply no kevlar belt in existence that would fit the Buddy or just no belts in the states? Just curious.

Thanks

Kaos · Post by **Kaos** » Mon Sep 22, 2008 3:04 am

BuddyLicious wrote:Hey Kaos & Docutech,

I assume your are using your stock belt? I was just wondering since it seems from reading different threads there isn't a known belt to fit.Also I'm assuming there is not a best weight set up as again I'm reading about different weights being used.So at least some of the weight set up is a personal choice? Lastly do you think there is simply no kevlar belt in existence that would fit the Buddy or just no belts in the states? Just curious.

Thanks

Yep, stock belt. I've seen hints that Scooterworks can get belts even though they're not listed on their site. I've never seen a kevlar belt that was the right length, but I would think any kevlar belt of the right length should fit.

Weights have a lot to do with personal preference. They basically control what RPM range your Buddy runs in, so you can tweak with them to get more power, or use lighter ones to run high RPM's for quick off the line.
I've had good luck with 11g Dr Pulley sliders in the stock variator, and a mix of 10.5's and 11's in the Dr Pulley variator SEEMS like about right. I'm tuning mine to spend the most time possible in the highest power band, so I'll end up with a good mix of off the line and top speed. I was able to pass 80MPH with the 11g's in the stock variator.

Post by **ericalm** » Mon Sep 22, 2008 5:16 am

In the MRP variator swap video on YouTube, they use a Pollini belt. They do not, interestingly, use the MRP belt which doesn't actually fit. They also don't run the scooter to show the Pollini actually fits right, so who knows?

docutech · Post by **docutech** » Mon Sep 22, 2008 2:37 pm

Well, after some research I found the proper size belt for the Buddy 125.

743mm(length) 20mm(width) 28(tooth angle)

I was able to find some on Ebay but unfortunately they are in Taiwan.

Kaos · Post by **Kaos** » Mon Sep 22, 2008 3:21 pm

docutech wrote:Well, after some research I found the proper size belt for the Buddy 125.

743mm(length) 20mm(width) 28(tooth angle)

I was able to find some on Ebay but unfortunately they are in Taiwan.

Order it anyway, I've ordered parts from Taiwan via ebay before with great results.

docutech · Post by **docutech** » Mon Sep 22, 2008 3:29 pm

I am awaiting a response from Scootertronics regarding a refund or replacement (if they indeed have the correct size kevlar belt in stock)

Here is the link to the Ebay auction:
http://cgi.ebay.com/ebaymotors/ws/eBayI ... 2761.l1259

The tooth angle on the above belt is 30 degrees, I don't think it should be that big of a difference (fingers crossed)

Kaos · Post by **Kaos** » Mon Sep 22, 2008 3:58 pm

docutech wrote:I am awaiting a response from Scootertronics regarding a refund or replacement (if they indeed have the correct size kevlar belt in stock)

Here is the link to the Ebay auction:
http://cgi.ebay.com/ebaymotors/ws/eBayI ... 2761.l1259

The tooth angle on the above belt is 30 degrees, I don't think it should be that big of a difference (fingers crossed)

Yeah, that doesn't seem like it would make a big difference.

On a side note, I think 10.5g/11g mixed sliders would be perfect IF I had lower RPM clutch springs. It seems to be a bit out of it's power band off the line, but has good power once I start getting up to speed. But so far I'm happy with the upgrade.

jfrost2 · Post by **jfrost2** » Mon Sep 22, 2008 4:06 pm

Be warned though if you use weights that will rocket your bottom end, the engine will be running much higher rpm's low end that your fuel economy may be altered. You'll still get good gas mileage, but not what is as good as stock.

docutech · Post by **docutech** » Mon Sep 22, 2008 4:09 pm

jfrost2 wrote:Be warned though if you use weights that will rocket your bottom end, the engine will be running much higher rpm's low end that your fuel economy may be altered. You'll still get good gas mileage, but not what is as good as stock.

So installing all 11g weights would eliminate the high rev's?

Kaos · Post by **Kaos** » Mon Sep 22, 2008 4:12 pm

jfrost2 wrote:Be warned though if you use weights that will rocket your bottom end, the engine will be running much higher rpm's low end that your fuel economy may be altered. You'll still get good gas mileage, but not what is as good as stock.

I'm aware of that. I've been constantly getting around 100mpg, I think even if it drops to 70mpg I really won't care

Its worth it to me to increase performance at the cost of some gas milage. Though in most of the hotrods I've built, running at a higher RPM that was in the motor's power band actually resulted in BETTER gas milage as long as I wasn't running it pedal to the floor all the time. This is because I was producing more power at that RPM so it required less throttle/gas usage to maintain the speed I wanted.

I'm not really going for bottom end anyway, I'm going for middle power band. Yes this does mean SOME increase in RPMs, but I'm still not winding it that high. I've gone from the stock 11.5g rollers to 10.5g/11g mixed sliders, so its not a huge increase in RPM. My Buddy was just running a bit under the RPMs to put it in the optimal powerband for my motor.

Kaos · Post by **Kaos** » Mon Sep 22, 2008 4:14 pm

docutech wrote:
jfrost2 wrote:Be warned though if you use weights that will rocket your bottom end, the engine will be running much higher rpm's low end that your fuel economy may be altered. You'll still get good gas mileage, but not what is as good as stock.
So installing all 11g weights would eliminate the high rev's?

It seems to be reving high initially partially due to the Dr Pulley's more aggressive initial ramp and the clutch not engaging quickly enough, so the motor initially revs higher than it's power band. 11g weights would solve this, but likely you'd end up with more over all power if you stayed with the lighter weights and got lower RPM clutch springs.

docutech · Post by **docutech** » Mon Sep 22, 2008 4:16 pm

I love this place. Thanks so much for all the info. By the way, I found a replacement kevlar belt for the Buddy 125 locally:

http://www.worldofscooterparts.com/belt ... evlar.aspx

Great price too!

docutech · Post by **docutech** » Mon Sep 22, 2008 4:20 pm

Kaos wrote:It seems to be reving high initially partially due to the Dr Pulley's more aggressive initial ramp and the clutch not engaging quickly enough, so the motor initially revs higher than it's power band. 11g weights would solve this, but likely you'd end up with more over all power if you stayed with the lighter weights and got lower RPM clutch springs.

So installing new clutch springs would help to engage the clutch quicker? Sorry for all the dumb questions, I am trying to figure this stuff out...

Kaos · Post by **Kaos** » Mon Sep 22, 2008 4:23 pm

docutech wrote:
Kaos wrote:It seems to be reving high initially partially due to the Dr Pulley's more aggressive initial ramp and the clutch not engaging quickly enough, so the motor initially revs higher than it's power band. 11g weights would solve this, but likely you'd end up with more over all power if you stayed with the lighter weights and got lower RPM clutch springs.
So installing new clutch springs would help to engage the clutch quicker? Sorry for all the dumb questions, I am trying to figure this stuff out...

Heh any question you can learn from is not a dumb question

Yes, you can change the engagement point of the clutch by using different strength clutch springs. I've always felt that the clutch on the Buddy was a little late on the engagement anyway, but its 10x worse with lighter weights and a more aggressive variator. I think MikieTaps has swapped out his clutch springs with good results.

jfrost2 · Post by **jfrost2** » Mon Sep 22, 2008 4:36 pm

Well, no one has really said if a DR pulley variator itself with 11 or 10g sliders will kill gas mileage, but I'm sure it does somewhat effect it, even if just a little. Clutch springs and a performance CDI will eat gas too.

Kaos · Post by **Kaos** » Mon Sep 22, 2008 4:37 pm

jfrost2 wrote:Well, no one has really said if a DR pulley variator itself with 11 or 10g sliders will kill gas mileage, but I'm sure it does somewhat effect it, even if just a little. Clutch springs and a performance CDI will eat gas too.

Yeah, It'll have some effect, every change in parts will. I'll let you know after I get a few miles on mine what the effect on the gas milage is(positive or negative).

jfrost2 · Post by **jfrost2** » Mon Sep 22, 2008 4:41 pm

Some people just have 10 or 11g sliders in the stock buddy variator, and they claim it doesnt add much performance or kill gas mileage, they just say it allows higher top end. But with the DR pulley variator, that's using the slider's to their max potential, and that no matter what is used in it, it will eat gas.

Kaos · Post by **Kaos** » Mon Sep 22, 2008 4:50 pm

jfrost2 wrote:Some people just have 10 or 11g sliders in the stock buddy variator, and they claim it doesnt add much performance or kill gas mileage, they just say it allows higher top end. But with the DR pulley variator, that's using the slider's to their max potential, and that no matter what is used in it, it will eat gas.

I'll probably agree with that

I did notice a bit of a performance increase with 11g sliders in the stock variator.

Kaos · Post by **Kaos** » Mon Sep 22, 2008 10:32 pm

So I swapped back in all 11g sliders when I got home from work, and I'll definately be leaving it that way. It had lost a fair amount of top end(15MPH) with the 10.5g/11g mixed sliders, I think mostly due to the
clutch not having the staying power it needs. But the mixed sliders did have a noticable amount more low end torque. I'll probably try it again after I swap in some 1500RPM clutch springs(Heck they're only 8 bucks, I can talk my wife into that!)

docutech · Post by **docutech** » Mon Sep 22, 2008 11:05 pm

I will try 11g all around as well. I will post my findings afterwards.

ScootingInTheRain · Post by **ScootingInTheRain** » Mon Sep 22, 2008 11:23 pm

One question -

What about the spacing washers? In the instructions, it sez to install the number of washers (up to 3) to change the behavior. Fewer washers gives higher top speed, more washers give quicker low-end speed but decreased top speed, etc. (not quite sure I got that right)

How many spacing washers did you put in?

Thanks,
SITR

docutech · Post by **docutech** » Mon Sep 22, 2008 11:24 pm

I put in 2.

ScootingInTheRain · Post by **ScootingInTheRain** » Mon Sep 22, 2008 11:25 pm

docutech wrote:I put in 2.

Did you apply any rules to arrive at 2, or was it just a guess?

Thanks
SITR

Kaos · Post by **Kaos** » Mon Sep 22, 2008 11:26 pm

ScootingInTheRain wrote:One question -

What about the spacing washers? In the instructions, it sez to install the number of washers (up to 3) to change the behavior. Fewer washers gives higher top speed, more washers give quicker low-end speed but decreased top speed, etc. (not quite sure I got that right)

How many spacing washers did you put in?

Thanks,
SITR

I tried everything from none to 3. I wasn't comfortable with all three being in there as it didn't leave much of the teeth out where the kickstart washer could grab them. I didn't notice a HUGE difference with them or without them, but they were good for some minor fine-tuning. I'm currently running without them, but will probably toss 1 or 2 back in to play with later. I've had my variator out about 10 times in the last 2 days tinkering with different combos of weights/spacers/whatnot. I'm gonna leave it alone for a while

docutech · Post by **docutech** » Mon Sep 22, 2008 11:33 pm

ScootingInTheRain wrote:
docutech wrote:I put in 2.
Did you apply any rules to arrive at 2, or was it just a guess?

Thanks
SITR

Technically I didn't put them in, my mechanic did. He said something about 1 being below the torque threshold, 2 being even and 3 being above the threshold.

What ever that means...

babblefish · Post by **babblefish** » Mon Sep 22, 2008 11:34 pm

The washers limit a scooter's top speed, so the more that are installed, the less your top end will be. This is one of the techniques used to limit (restrict) a 50cc scooter to 30mph.

docutech · Post by **docutech** » Mon Sep 22, 2008 11:36 pm

babblefish wrote:The washers limit a scooter's top speed, so the more that are installed, the less your top end will be. This is one of the techniques used to limit (restrict) a 50cc scooter to 30mph.

Interesting.

Modern Buddy

Buddy 125 variator upgrade with pictures

Buddy 125 variator upgrade with pictures