Buddy 150/GY6 parts interchangeability?

ohiotj · Post by **ohiotj** » Fri Sep 05, 2014 5:01 pm

This summer, as an addition to my daily rider 09 Buddy 125, I got a deal on a 2006 Buddy 125, with a later buddy 150 engine, and a bunch of spare parts. I've decided to keep the 2009 mostly stock-ish, to keep it reliable, but am thinking of going wild on the 2006 Buddy.

The 150 engine that came with it has low compression (high mileage), so is in need of at least a top end rebuild. But, I'm thinking of taking it beyond a new big bore kit, especially since it wouldn't surprise me if it at least needs new crank bearings. One limitation with using the stock crank, though, is the number of teeth on the timing gear is unique to the buddy(Edit: This may only be true of the 125 engine, not the 150, I need to do a little more research), so GY6 performance cams don't work off the shelf. Has anyone managed to fit a stock GY6 crank to a buddy? If this is doable, it opens up the option of stroker cranks and performance cams for me.

Hoping someone who's done it can chime in. If not, during the fall/winter, I'll see about tearing down the buddy engine, and taking some measurements against a stock GY6 case and crank I have laying around. If I do, I'll create a list with three categories:
1. Parts that can be swapped with no changes (seems like variators/weights and clutches fit in this category)
2. Parts that can be replaced, but may require other changes
3. Parts that can't be swapped without extensive work (IIRC, transfer gears in the final drive fit this category)[/b]

ohiotj · Post by **ohiotj** » Fri Sep 05, 2014 5:10 pm

And in doing a few more minutes of looking, I may have put my foot in my mouth over a at least a bit of what is in the original post. It seems it is possible the buddy 150 engine can accomodate performance cams with no changes, its the 125 that may not...

lovemysan · Post by **lovemysan** » Sat Sep 06, 2014 1:37 pm

You can run any generic gy6 cam in buddy 125 so long as you swap the stock cam gear onto the new cam. I do this with a ruler, scribe, piece of pipe, fire wrench, freezer, and a bench vise.....and gloves.

Gy6 head and base gaskets work fine as well. The case and gear box gaskets are oem specific(and great quality).

Genuine uses standard bearings made by "tpi". They seem reasonably durable. But because they are a standard sizes you can get 95% from a bearing supply house off the shelf in a good brand like koyo or skf.

All the buddy gy6 cranks are unique. They have longer splines on the variator side to accommodate the kick start washer. You can install a generic crank but you loose the kick start or have to get kick start washer doweled to the variator. You would also need to verify the tooth count of the cam drive gear when swapping from a 125 to a 150 crank. The 125 crank also has a 13mm wrist pin.
125cc 60mm stroke 13mm wrist pin
150cc 57.8mm stroke 15mm wrist pin

Taida makes a 61mm crank that looks like it will fit. For $207 shipped
Ttmrc makes a 61.3mm crank that's sold in a complete kit including a crank, 4 valve head, cylinder etc for around $625 shipped.

For cylinders the prima 161cc 58.5mm is the simplest bolt on for the 125. I'd guess that the ncy branded kit would work as well so long as it included the cylinder spacer. Again you're looking for the 13mm wrist pin and there isn't much available. The 150 will take most of the generic parts.

For heads the generic gy6 heads are fine. It's recommended you put the size corresponding to the cylinder on. You can put one smaller than the cylinder but not larger as the valves can strike. I'm running the ncy 58.5mm head. With stainless valves, taida 14k springs, and taida titanium spring retainers.

Gears, there is no after market available but there are 3 sets available.

Psycho ????ratio but numerically higher than stock 125.

Psycho 9.5 to 1
125 9.07 to 1
150/170 8.25 to 1

Cdi and coil
Don't bother with the cheap aftermarket. The stock cdi has no limiter. The ones with adjustable curves cost around $140 ish. You can slot the mount tab of the ignition pickup and get 1.5-2 degrees of advance the old school way. I've tried this but am not sure how well it works. There are off set timing keys that work as well. But they can shear off. The big advantage of the Cdi advance is easy starting.

Xsquader · Post by **Xsquader** » Tue Sep 09, 2014 10:00 pm

Anyone know if this gy6 ignition works on a buddy 50?

http://www.ebay.com/itm/Key-Switch-Igni ... 1056305341

Thieves ruined my ignition, my turn signals, and my speedometer, but mainly my ignition. Been using the kickstarter with the ignition unplugged, now teeth are worn on both of the things in the kickstarter (forgive me I don't know the technical names for this stuff) so now I can't start it at all. I am disabled and make 700 bucks a month so trying to get it working as cheap as possible as it's my main form of transportation.

lovemysan · Post by **lovemysan** » Wed Sep 10, 2014 5:06 am

I don't think that will fit. I suggest you remove the lock from the bike so you can compare it to others. Look at the Milano ignition switch. It looks similar to me. http://www.scrappydogscooters.com/site/ ... .html#2900

You could also completely bypass the switch by installing a simple momentary switch to apply 12v power to the starter solenoid.

dana · Post by **dana** » Mon Jun 08, 2015 7:43 pm

Good info on the crank sizes. Thanks.

Is there a crank with a 15mm wrist pin that will fit my Buddy 125 motor? I wore out a NCY cylinder kit I got from Scooterworks. The new one I picked up looks to be nice Taiwanese quality, but has a 15mm wrist pin rather an 13mm like the old kit.

Thoughts on finding a new crank with 15mm pin vs. buying a new NCY kit with 13mm wrist pit?

Thx in advance for the reply on this old thread.

-D

lovemysan wrote:You can run any generic gy6 cam in buddy 125 so long as you swap the stock cam gear onto the new cam. I do this with a ruler, scribe, piece of pipe, fire wrench, freezer, and a bench vise.....and gloves.

Gy6 head and base gaskets work fine as well. The case and gear box gaskets are oem specific(and great quality).

Genuine uses standard bearings made by "tpi". They seem reasonably durable. But because they are a standard sizes you can get 95% from a bearing supply house off the shelf in a good brand like koyo or skf.

All the buddy gy6 cranks are unique. They have longer splines on the variator side to accommodate the kick start washer. You can install a generic crank but you loose the kick start or have to get kick start washer doweled to the variator. You would also need to verify the tooth count of the cam drive gear when swapping from a 125 to a 150 crank. The 125 crank also has a 13mm wrist pin.
125cc 60mm stroke 13mm wrist pin
150cc 57.8mm stroke 15mm wrist pin

Taida makes a 61mm crank that looks like it will fit. For $207 shipped
Ttmrc makes a 61.3mm crank that's sold in a complete kit including a crank, 4 valve head, cylinder etc for around $625 shipped.

For cylinders the prima 161cc 58.5mm is the simplest bolt on for the 125. I'd guess that the ncy branded kit would work as well so long as it included the cylinder spacer. Again you're looking for the 13mm wrist pin and there isn't much available. The 150 will take most of the generic parts.

For heads the generic gy6 heads are fine. It's recommended you put the size corresponding to the cylinder on. You can put one smaller than the cylinder but not larger as the valves can strike. I'm running the ncy 58.5mm head. With stainless valves, taida 14k springs, and taida titanium spring retainers.

Gears, there is no after market available but there are 3 sets available.

Psycho ????ratio but numerically higher than stock 125.

Psycho 9.5 to 1
125 9.07 to 1
150/170 8.25 to 1

Cdi and coil
Don't bother with the cheap aftermarket. The stock cdi has no limiter. The ones with adjustable curves cost around $140 ish. You can slot the mount tab of the ignition pickup and get 1.5-2 degrees of advance the old school way. I've tried this but am not sure how well it works. There are off set timing keys that work as well. But they can shear off. The big advantage of the Cdi advance is easy starting.

lovemysan · Post by **lovemysan** » Thu Jun 11, 2015 10:18 pm

Easiest to get will be a crank for a buddy 150 through your dealer. You will lose displacement though because the 125 has a 60mm stroke and the 150 crank has a 57.8mm stroke. There is an 61.3mm crank available through taida, its for the PGO gmax 150. Also ttmrc was selling a engine kit on ebay, I emailed them several times and they were able to supply the correct crank as well. The main difference was the ttmrc crank had a nice forged rod.

Now you can use a generic gy6 crank but you will lose the kickstart. Mine is a necessity.

dana · Post by **dana** » Thu Jun 11, 2015 10:23 pm

> There is an 61.3mm crank available through taida, its for the PGO gmax 150

Fantastic. I'll investigate. Much appreciated.

-D

lovemysan wrote:Easiest to get will be a crank for a buddy 150 through your dealer. You will lose displacement though because the 125 has a 60mm stroke and the 150 crank has a 57.8mm stroke. There is an 61.3mm crank available through taida, its for the PGO gmax 150. Also ttmrc was selling a engine kit on ebay, I emailed them several times and they were able to supply the correct crank as well. The main difference was the ttmrc crank had a nice forged rod.

Now you can use a generic gy6 crank but you will lose the kickstart. Mine is a necessity.

babblefish · Post by **babblefish** » Fri Jun 12, 2015 7:45 am

You might want to read through my Blur engine rebuild here:
topic16629.html

Though the Blur uses a 150cc engine, some of the info might be of interest to you.