Stroked problems

[ls1_boy]

Does anyone make a special cylinder for a 4mm stoked 400ex? Because I'm having the problem it's not turning completely over it's hitting at BDC. I have a vertex piston 23234400 reads 88.97 and plus 4.0 on the top what do I do please help

[MtnEX]

Im not well studied on strokers for the EX but sometimes cases and skirts need clearanced for this stuff.

You should contact the MFG of the crank.

[DragonGunner]

Don't need a special cylinder for stroker unless its way bigger bore. Stroker cranks have there own special pistons. The don't always mix match with different brands. Like MtnEX said sounds like the skirts of the piston need to be grinder down…how sure you got a stroker crank in it? Hopefully somebody didn't just tell you that when selling.

[Wheelie]

The piston skirt is probably hitting the crank throws at BDC. You'll need to buy a custom piston or shave the skirt down on the one you already have. How does it look at TDC?