piaggio 70 small end bearing fail

[diesel27]

Wanting to know how / why small end bearing got pounded ? NRG , S6 sport pro and new doppler enduro crank ran strong for 2000 km . Want to avoid same problem before my new build . Any ideas are appreciated .

 

[TuningMatters]

Mhm, hard to tell, could be overrevving due to too low gear ratio, tho my guess would be its just the Doppler shit quality that hit you. Get a MHR silver bearing as a replacement and you should be good!

 

[diesel27]

Thanks for that . I do have Longer g/box ratio and only rev to 11k max . Std bearing width is 13 mm , is it better again to go oversize to the 15 mm ? I was pre mixing at 33:1 and piston and bore looked good . Crankshaft still looks ok too ...

 

[TuningMatters]

Hey, really sounds like a parts failure. I believe you mean 12mm. 13mm would already be oversize on Piaggio. I'd stick with stock, it should really not be a problem to run a 12mm bearing with your setup!

 

[diesel27]

Ok thanks TuningMatters . I will try that .

By the way , does anyone know how a s6 racing cylinder coupled with an r1200 exhaust would perform if only reved to 11k ? As I think that is the limit of my purejet cdi including conversion kit ???

 

[TuningMatters]

http://www.tuningmatters.com/news/news-stage6-sport-pro-mkii-and-stage6-racing-mkii/

Here you go!