R9/R9i motor

[Southpaw32]

From the information I have been able to find/acquire, the R9 has a modified GY6 engine.
A lot of mods/accessories will work, but things like a Big Bore Kit might have some issues.

Granted, this is what I've been told.
I wasn't planning on a BBK, but I would like to do some "reasonable" tweaks to get some better performance.

[unknownuser01]

I've heard the same about compatibility. I haven't heard about any issues with big bore kits though. Can you be more specific? Personally, my R9 has excellent stock performance. I pretty easily push 60 mph. I couldn't ask much more from a scooter...

[The Professor]

I would be interested in finding out the answer to this as well since I removed the engine from my R9 and installed it in my Honda Ruckus. Although it is fast already, I would always enjoy going faster

[sparc5]

Does anyone know the exact model of the engine?  Usually three numbers and three letters?  60MPH is poor performance for a 150cc'er.   My Buddy 150 could do 65 even in strong head winds, and much stronger acceleration.  I'm thinking of putting in a big bore kit.