stock to 4mm crank on ported cyls

[assbandit]

i have stock cylinders that ive had ported and i am looking to put a 4mm or 7mm stroker crank in it. I heard i might not be able to why??

[njbanshee]

You can do anything you want with enough money.

[jbooker82]

When they port the stock stroke cylinders they raise the ports x amount depending on the port job. When you put a 4 mill stroker crank in the piston falls down in the bore 2mm and comes up out of the bore 2 mm. Total of +4. When they port for the 4 mill they first lower the ports down 2mm, because the piston is 2 mm lower at BDC. Well you have your cylinders that have already have had the ports opeaned up, then you try to lower them for the stroker crank, now your ports are way to large and performance suffers.

 

josh

[Wildcardracing]

Most builders trail/woods/MX ports can be recut for a 4mil, but it may end up with more duration than before, which will move the power band up in the rpms. Usually dune ports or anything more aggressive can't be ported for a stroker. As far as the seven mil it will only be possible if the stock port timings have not been altered much if at all.

[assbandit]

thanks for the info. i guess i will have to wait on that!!!