New Top End for My CRM using CR250 Parts

John McD · Post by **John McD** » 12 Dec 2006, 20:01

I've received the new piston kit and rod kit from Wiseco for my CRM rebuild. I can say for sure that the CR piston is not an exact replacement for the CRM item.
The distance between the pin and crown is about 0.020\" longer on the CR and the pin is 9mm for the CR vs. 10mm for the CRM. However, it appears the rod for the CR is 0.020\" shorter so that may make-up for the pin to crown difference. Additionally the CR pin is about 1mm smaller in diameter than the CRM piece.
I have everything at the machinist's now for measuring and fitment. On first glance he thinks it can be made to work. The pistin I ordered is 68mm, which will yield a dispalcement of 262cc. Additionally it is forged rather than cast and lighter than the stock unit.
I also purchased a FMF rear cone for the pipe and a set of Boyesen reeds. I hope this all will liven the old girl up a little.
I let you know when I have word on whether it will all work, and will provide exact dimensions if anyone wants to reproduce the rebuild.
If it all works I figure to have saved about $300 including postage, not counting the machining.

Post by **Gwyn** » 12 Dec 2006, 20:14

Nice one john. Keep up the good work, and thanks for keeping us informed on your progress. All the information will no doubt come in very handy one day. Cheers. Gwyn.

edarter · Post by **edarter** » 13 Dec 2006, 19:45

yes cheers John - will be watching this one with interest !

Ed