YZ144 case mod

[YZ-212]

Just got my cylinder back and before I jump into grinding the cases I want to make sure I'm doing it correctly. From the reading here and from Erics book I'm still a bit unsure of how mutch material I need to remove from the case. I understand the grinding is to be done between the cylinder skirt and crank on the exhaust side of the cases.

I'm worried I'm going to remove too mutch of the case so I want to clarify this. Do I need to grind all the way to the crank? Does any one have a clear picture of the mod?

Thanks!

 

[YZ-212]

No one?? I'm taking in my bottom end to have rebuilt this weekend and would like to have the mod done before so I don't get any metal in the case.

 

[Pete Payne]

Yes grind all the way down to the crank opening . It is best to do this with the crank and the bearings out. You need two things side clearance , about 1mm , and clearance at BDC, this is why you grind all the way down to the crank .