Buddy 125 Big Bore

longqat · Post by **longqat** » Sun Sep 27, 2015 1:10 am

Hi, first post on the forum!

I've been riding on my Buddy 125 for some time and I quite love it. But the areas I drive around are extremely hilly, and the engine seems a bit anemic sometimes. I've taken the scooter apart and started changing out parts for maintenance, and I figured now is a better time than ever to try and get the most out of my scooter. I already have 10 gram sliding weights ordered, but I was thinking about lining up something else.

If I went with a 161cc big bore kit head, would adjusting my jetting be all I need to do for the carb or would a larger carb be necessary? It has the stock as of now.

Would a transmission upgrade be a good idea if I didn't go with the big bore kit?

Which would be more reccomendable?

Am I missing anything?

Thanks for your time.

babblefish · Post by **babblefish** » Sun Sep 27, 2015 4:26 am

Welcome to MB.
A BB kit would certainly give you the extra power for hills, but unless you're going to change the crankshaft too, make sure you get a BB kit meant for a 125cc engine because the piston wrist pin is smaller on a 125 vs a 150cc engine. You may also need to get a different head that is meant for the bigger bore, otherwise the compression ratio might get too high.
I believe the 125 uses a 24mm carb so you should be ok with just a jet change (106-108) and possibly an adjustment to the needle jet height.
A performance exhaust system might also be of some benefit if you can find one for your Buddy.
Save yourself some agravation and stick with the stock airfilter box.

longqat · Post by **longqat** » Sun Sep 27, 2015 5:38 am

babblefish wrote:Welcome to MB.
A BB kit would certainly give you the extra power for hills, but unless you're going to change the crankshaft too, make sure you get a BB kit meant for a 125cc engine because the piston wrist pin is smaller on a 125 vs a 150cc engine. You may also need to get a different head that is meant for the bigger bore, otherwise the compression ratio might get too high.
I believe the 125 uses a 24mm carb so you should be ok with just a jet change (106-108) and possibly an adjustment to the needle jet height.
A performance exhaust system might also be of some benefit if you can find one for your Buddy.
Save yourself some agravation and stick with the stock airfilter box.

Thanks for your help!
A big bore kit is certainly one of the more pricier options, but it seems like you get out what you put in. And I think the Stage 2 kit is certified for a 125, but I'm not entirely sure as it might just be parts commonalities between the 125 and 150. If I bought just that it should work fine I assume.
I think I'll hold out for the bore kit until I can afford a different head, as that seems to be the best combo. Not even sure if pouring that much money into my scooter would make much sense.

Anyways, on a side note, how do you remove the tensioning bolt for the variator assembly?

BuddyRaton · Post by **BuddyRaton** » Sun Sep 27, 2015 12:11 pm

Me. Fish makes good points.

Also the stroke is longer on the 125.

Here is what I did. BBK for a 125, I used the old head, opened up the air box, went to a 26 mm carb and an NCY pipe.

I have been very happy with it, much better torque..it will wheelie if not careful!

sc00ter · Post by **sc00ter** » Sun Sep 27, 2015 2:37 pm

I have had great results having the stock heads "optimized" at Vance and Hines for a rework at their machine shop. The stock heads are pretty good quality as stock, but are mass produced to a tolerance. Optimizing it makes sure its the best they can be. Its a little performance secret that I have always used, and best of all it keeps your mpg's in check because you are still running the stock heads. I have even had a aftermarket big valve head for a Zuma 125 reworked by them. The difference was night and day afterwards. They did say the aftermarket big valve head was not manufactured to the best specs originally.

babblefish · Post by **babblefish** » Tue Sep 29, 2015 5:35 am

BuddyRaton wrote:Me. Fish makes good points.

Also the stroke is longer on the 125.

Here is what I did. BBK for a 125, I used the old head, opened up the air box, went to a 26 mm carb and an NCY pipe.

I have been very happy with it, much better torque..it will wheelie if not careful!

Which 26mm carb did you get? The one with the yellow zinc metal top or the black plastic top? Did you need to rejet? Thanks.

BuddyRaton · Post by **BuddyRaton** » Wed Sep 30, 2015 10:34 pm

babblefish wrote:
BuddyRaton wrote:Me. Fish makes good points.

Also the stroke is longer on the 125.

Here is what I did. BBK for a 125, I used the old head, opened up the air box, went to a 26 mm carb and an NCY pipe.

I have been very happy with it, much better torque..it will wheelie if not careful!
Which 26mm carb did you get? The one with the yellow zinc metal top or the black plastic top? Did you need to rejet? Thanks.

I'll have to take a look but I'm pretty sure it was the zinc. I didn't rejet as it ran great right after install. I don't have the choke wired in but that hasn't been a problem.

Snap · Post by **Snap** » Sat Oct 10, 2015 2:26 am

I've got a new BB kit and big valve head to sell if you're interested.