custom made pit bike 125 engine advice

[pommie]

im making a custom made 125cc i need help or advice for parts such as engine carby the whole kit really any help i would be greatly thankful for

thanks pommie

 

[theMINDLESSone]

got a budget for engine?

 

[The_GDFP]

By "custom made", do you mean fabricated from scratch, or assembled from random bits of other complete cycles?