buddy 125 upgear kit, Confirmed!

lovemysan · Post by **lovemysan** » Fri Jul 18, 2014 5:20 am

I finished my gearbox rebuild tonight. I replaced every bearing but the sealed output. Genuine kept sending the dealer an open bearing that was a 25mm verses the correct sealed 22mm. I ended up reusing my old one as it felt fine. I purchased all new 170i gears, shafts and seals for $120. My local dealer is always cheaper than the web prices I see. I could have reused my old output shaft and saved $30. I got nice skf bearings from a local distributor for $40. The 170i gears swapped right into the case with no issues. I rode around the neighborhood and everything feels good. I'll give a ride report in a few days. I'm still tuning the koso clutch I installed last week but I think with these new gears I'll move down to 13 gr sliders.

I did some research today at the dealer. The buddy 125,150, &170, blur 150/220, hooligan 170 all share the same gearbox cover gasket. I wasnt able to find the blur 220 gearing info. The hooligan service manual isnt out yet. The buddy 125 has a gear ratio of 9.06 to 1. The 170i has a ratio of 8.25 to 1. Maybe I'm wrong but I assume the 170i gear set is a bolt in affair. Going to the 170 gear set would theoretically give me 6-7 mph increase in top speed. My current level ground top speed is 58-60 mph or 74bmph.

ohiotj · Post by **ohiotj** » Fri Jul 18, 2014 2:43 pm

It sounds like a definitely possiblity. I seem to recall someone here went through a lot of trouble adapting GY6 gears to their buddy and had all sorts of problems, so it'd be nice to have a solution using all PGO-branded parts. I thought the Buddy 150 also has different gearing than the 125, too, but I have no idea what it is.

I get about 56-57 MPH (GPS) on level ground on a Buddy 125 with a Prima pipe and NCY transmission kit, so you should be making a ton more power than me which points to gearing being your limitation.

lovemysan · Post by **lovemysan** » Sat Jul 19, 2014 3:59 am

My completely stock 125 will hit 52 gps and 63 bmph. I've never actually topped out the 161 bike. I gave it quick blast but let out of it. Spending much time over 9500 rpms will significantly shorten the engine life. As for power I roll raced a 190 kitted lambretta series 2 with a chamber and big carb, I had no trouble pulling away. From a dead stop it would be worse. Currently I'm chasing a nasty driveline growling. So far I replaced all the transmission bearings, clutch and belt. I think the gears might be worn out. I have a spare set I'm going to try. I think regearing would probably cost around $150 in parts.

wheelbender6 · Post by **wheelbender6** » Wed Jul 23, 2014 2:04 am

Increasing acceleration is doable. Increasing top speed is tougher. Before I tried any gear changes, I would try a taller rear tire to see how the Buddy responds to taller gearing. Just my opinion.

lovemysan · Post by **lovemysan** » Sat Jul 26, 2014 4:52 am

wheelbender6 wrote:Increasing acceleration is doable. Increasing top speed is tougher. Before I tried any gear changes, I would try a taller rear tire to see how the Buddy responds to taller gearing. Just my opinion.

I don't think you can get a much larger tire. I think a 130/70 fits but its not any taller than the 100/90.

lovemysan · Post by **lovemysan** » Sun Jul 27, 2014 2:59 am

I got a 20 minute ride in today. She cruises at 55 mph GPS at 7500 rpms. I lost some acceleration due to the new clutch not being tuned yet. It still has enough torque to drag the rear rack in a wheelie. Off the line rpms hit 6500 till about 30 mph. This is below peak power. I'm going to raise it 500 rpms at least.

Old top speed was 60 mph in much cooler weather.
New top speed is 64 mph. Thats 77 bmph per my old stock speedo. I'm happy with that number. I'm still running the stock carb and stock airbox(modified). I think with a 28mm flatside and a open filter I could pick up another 3-6 mph. I also think I could vent my belt cover and pick up 1-2 mph as the belt gets hot and smells after a top speed run.

thatvwbusguy · Post by **thatvwbusguy** » Sun Jul 27, 2014 6:25 am

Venting the CVT cover to let the belt run cooler is definitely a good idea. Keeping the belt in good condition will ensure that it is wide enough to ride at maximum height on the front pulley to maximize your gear ratio.

While you have the cover off, mark your variator with a sharpie from the center out (like kids draw sunrays), then ride for a few days and see how much of the marks are left on the outer edge of the pulley.

This simple visual feedback will help you dial in your rollers/sliders and will also tell you when you have reached the maximum speed that the variator will allow. It is usually best to stop 3-4mm from the outer edge of the pulley to avoid the possibility of throwing the belt on a long downhill run under full power.

ohiotj · Post by **ohiotj** » Sun Jul 27, 2014 9:09 pm

I've not taken apart the drive on a Buddy yet. Was it a simple matter of one gear that slips into place, and pressing the other gear off the shaft? Then reversing for the install?

lovemysan · Post by **lovemysan** » Sun Jul 27, 2014 11:05 pm

It's a straight forward process. The input shaft needs the bearing pressed off. I used a vice and big piece of copper pipe as a sleeve. To reinstall I heated the bearing to 225f and froze the shaft and it dropped right on with no issues. I froZe all the bearings during install I also heated the cases to avoid pounding the bearings in. Make sure and order a new gasket and both seals they are cheap. There is a youtube video of gear install on a qmb139 gy6 that is great.

ohiotj · Post by **ohiotj** » Mon Jul 28, 2014 1:12 am

Thanks, done the job on a regular GY6 before, just didn't know how different the buddy was, since the gear sets had other differences.

I've got a buddy 150 engine with low compression sitting around. When I have time, I really should tear it open and try to catalog the difference between it and a "standard" GY6, unless someone's done it already.

lovemysan · Post by **lovemysan** » Mon Jul 28, 2014 4:14 pm

I forgot to mention that if your installing a new input shaft you can buy a brand new input bearing and completely avoid using a press.

az_slynch · Post by **az_slynch** » Mon Jul 28, 2014 7:37 pm

Nice detective work! It's always cool to find a bit more speed.

Hunting something similar for the Yager with some of the KymcoForum guys; they want lower RPMs for cruising speed. I might have found a primary upgear, but I can't say I want to dismantle my runner to do a tooth count.

lovemysan · Post by **lovemysan** » Mon Jul 28, 2014 9:48 pm

az_slynch wrote:Nice detective work! It's always cool to find a bit more speed.

Hunting something similar for the Yager with some of the KymcoForum guys; they want lower RPMs for cruising speed. I might have found a primary upgear, but I can't say I want to dismantle my runner to do a tooth count.

I've been told 5 times there wasn't an up gear available I just didn't believe them. I talked to the technical guy at Scooterworks 2 weeks ago I was preparing to order a psycho gear set based on some opinions I read here. He told me it was a higher ratio. And that I would lose top speed. I went to the dealer to order gaskets and he told me gearbox gaskets were all them same. I sat down and reviewed part numbers and went back to the dealer to consult the 170i manual for the tooth counts. I wonder if kymco list gear tooth counts. And you can find your overall ratio by counting the input revolutions to output revolutions.