engine rebuild

[toycoma98]

My engine started leaking oil so we gotta take it apart. BUT should we install a big bore, port polished head, performance cam, and remove all emissions while we're at it?

[Lostmycage]

My engine started leaking oil so we gotta take it apart. BUT should we install a big bore, port polished head, performance cam, and remove all emissions while we're at it?

1) Do you have a warranty to cover any mishaps... like an oil leak?

2) Do you have the funds and parts source for said modifications?

3) Do you really need approval?

4) Weren't you going to do this anyways?

If 1)=yes, STOP
If 2)=no, STOP
If 3)=yes, STOP... and re-evalutate how much value you place in strangers
If 4)=no, STOP and why did you ask.

As long as you didn't run into any STOPs, go for it! Sounds like it'll be a blast!

[Anachronism]

Eh, number 1 I don't view as that big of a deal. Its not like these things are expensive...

Both my scoots didn't make it through the warranty period before they got sweet voided.

[Lostmycage]

Right, the warranty is there to protect the owner from defects. An Oil leak is a pretty big defect, though. A Big bore kit, ported head... and all that other crap is useless if he's working with a bad casing.

If it's free, it's for me. If it's covered under warranty, then use the warranty.

If the warranty isn't an issue (I suspect as much based on the line of questioning) then who cares? Tear it down, rebuild it, and have a f***-load of fun doing so!

[toycoma98]

The seal on the fan/stator side is busted. Its still under warranty so i dont have to pay for labor, just the parts.

Should i go with a 155cc or go all out and put a 200cc?

I want it to be reliable though so i'm leaning more on the 155. But 200 sounds BADAZZ!

[Lostmycage]

A lot of folks have had good results with the 161 kit that Scooterworks sells. If they're willing to do the labor (since they have to take it down to the case) for free on an BB upgrade... that's pretty cool.

Who brings the PGO scooters to Guam? I'm guessing it's not Genuine, so the warranty terms are bound to be different.

[Kaos]

The seal on the fan/stator side is busted. Its still under warranty so i dont have to pay for labor, just the parts.

Should i go with a 155cc or go all out and put a 200cc?

I want it to be reliable though so i'm leaning more on the 155. But 200 sounds BADAZZ!

If you want reliable, don't do the 200cc. I know of two engines that have had one installed. Both didn't last long.

The 200cc requires a LOT of cutting of the case and removes a LOT of needed cooling material. You would need to add things like a water cooled head and radiator to have any real hope that it will survive.

[toycoma98]

So we're gonna put a 58.5mm big bore, big cam, and port polish the stock head. The side of the piston is coated and its a high compression (raised).

The only problem was the new performance piston has 15mm wristpin. Stock is 13mm.

The cylinder looks similar to this:

[Kaos]

So we're gonna put a 58.5mm big bore, big cam, and port polish the stock head. The side of the piston is coated and its a high compression (raised).

The only problem was the new performance piston has 15mm wristpin. Stock is 13mm.

The cylinder looks similar to this:

Um, how are you going to install it with the wrong wrist pin size? Gonna swap the crank too?

[toycoma98]

So we're gonna put a 58.5mm big bore, big cam, and port polish the stock head. The side of the piston is coated and its a high compression (raised).

The only problem was the new performance piston has 15mm wristpin. Stock is 13mm.

The cylinder looks similar to this:

Um, how are you going to install it with the wrong wrist pin size? Gonna swap the crank too?

Its a GY6 Big bore kit straight from Taiwan. I didn't order it, my friends went to Taiwan and bought a allot of it there. Its the latest technology for GY6 in Taiwan. All the ebay GY6 stuff are old technology.

The stock 125cc wrist pin is 13mm. The piston it came with is 15mm. Gonna have to make a sleeve adaptor to use the stock wrist pin. They are gonna use rollers (like the ones in the transmission) for the sleeves.

It will work. Scooter world can do anything.

[Anachronism]

So we're gonna put a 58.5mm big bore, big cam, and port polish the stock head. The side of the piston is coated and its a high compression (raised).

The only problem was the new performance piston has 15mm wristpin. Stock is 13mm.

The cylinder looks similar to this:

Um, how are you going to install it with the wrong wrist pin size? Gonna swap the crank too?

Its a GY6 Big bore kit straight from Taiwan. I didn't order it, my friends went to Taiwan and bought a allot of it there. Its the latest technology for GY6 in Taiwan. All the ebay GY6 stuff are old technology.

The stock 125cc wrist pin is 13mm. The piston it came with is 15mm. Gonna have to make a sleeve adaptor to use the stock wrist pin. They are gonna use rollers (like the ones in the transmission) for the sleeves.

It will work. Scooter world can do anything.

Um, its not an old/new technology thing. I see absolutely no reason to go this route vs. just getting the right parts. The double bearing idea sounds like a bad idea- what happens as the bearings wear and get even a little slop?

[jmkjr72]

for some of the 2 stroke stuff they make special bearings that way you can use a piston for a 12mm crank on a 10 mm crank
maybe they have these adapter bearings out there for the gy6

[toycoma98]

Um, how are you going to install it with the wrong wrist pin size? Gonna swap the crank too?

Its a GY6 Big bore kit straight from Taiwan. I didn't order it, my friends went to Taiwan and bought a allot of it there. Its the latest technology for GY6 in Taiwan. All the ebay GY6 stuff are old technology.

The stock 125cc wrist pin is 13mm. The piston it came with is 15mm. Gonna have to make a sleeve adaptor to use the stock wrist pin. They are gonna use rollers (like the ones in the transmission) for the sleeves.

It will work. Scooter world can do anything.

Um, its not an old/new technology thing. I see absolutely no reason to go this route vs. just getting the right parts. The double bearing idea sounds like a bad idea- what happens as the bearings wear and get even a little slop?

What i got compared to the ones on Ebay, The cylinder is ceramic coated, piston has a coating on the side and its higher compression, better chain, and its a better cam.

I just think its better than whats on Ebay. The ones on Ebay are just raw aluminum.


The wrist pin is not a bearing. With the sleeve adapter, it should be just fine.

[toycoma98]

for some of the 2 stroke stuff they make special bearings that way you can use a piston for a 12mm crank on a 10 mm crank
maybe they have these adapter bearings out there for the gy6

Yup, Like on my pocket bike engine, its a 10mm stock, there are sleeves to allow a 12mm piston to fit. But i just got a whole new 12mm full circle crank.

Anyways you got idea. I've searched but nothing. So machine shop it is.

[toycoma98]

So my brother has a Sym Mio 50cc 4-stroke. And i believe its a GY6 clone. I'm planning on putting a big bore in it

But should i get the NCY kit from scooterworks or the Ebay one?

[Kaos]

Its a GY6 Big bore kit straight from Taiwan. I didn't order it, my friends went to Taiwan and bought a allot of it there. Its the latest technology for GY6 in Taiwan. All the ebay GY6 stuff are old technology.

The stock 125cc wrist pin is 13mm. The piston it came with is 15mm. Gonna have to make a sleeve adaptor to use the stock wrist pin. They are gonna use rollers (like the ones in the transmission) for the sleeves.

It will work. Scooter world can do anything.

Um, its not an old/new technology thing. I see absolutely no reason to go this route vs. just getting the right parts. The double bearing idea sounds like a bad idea- what happens as the bearings wear and get even a little slop?

What i got compared to the ones on Ebay, The cylinder is ceramic coated, piston has a coating on the side and its higher compression, better chain, and its a better cam.

I just think its better than whats on Ebay. The ones on Ebay are just raw aluminum.


The wrist pin is not a bearing. With the sleeve adapter, it should be just fine.

While it true that many ebay kits are just basic cast iron cylinders, the Prima kit for the Buddy 125 is aluminum, ceramic coated, higher compression, etc as well, and has the correct 13mm wrist pin for the 125's

Sleeving the 12mm crank to fit a 10mm wrist pin is one thing, making an adapter to fit a 15mm wrist pin on a 13mm crank is entirely something else. That just seems like its not going to last long.

[toycoma98]

Decided to keep the stock cylinder. GY6 big bore didn't work out.

oh well.....


...I kinda like the gas mileage.