I have a stroker crank +4mm and my bike just have 65hp and I think my porting is not very good. Do you think that I need a special porting? please give me some links or pictures. thank you

 

If you had it ported for the stock stroke and try to put in a 4mm stroker it will not run worth a fu*k. You will have to have your cylinder re-ported for the right port timing for that crank.

 

It will also differ depending on whether or not you are running a spacer plate. The porting needs to be done by a degree wheel and also done to what type of riding and what pipes you are running. There are a ton of variables to factor in for proper performance. I am sorry, it's just not very cut and dry.Bubba

 

I agree with bubba the first question the technition will ask you when you want it ported is what pipe do you have.