Porting specs for a 92-95 RM250?? Worth the $$$?

[Hucker]

I was told by a local mechanic that a good mod to my bike would be to get it ported to the 92-95 RM250's porting spec's. I was also told that taking 1mm off the bottom would be a good idea. Seeing that i don't know to much about this, can anyone (Eric?) fill me in on if these mods would be worth the $$$?

Thanks :)

Bill

 

[EricGorr]

The 92-95 all ahve different port specs stock. Taking 1mm off the bottom of the cylinder is a great way to break the crank and the cases when the piston expands and smashes into the head. Of course free advice from a guy who wants to sell you new parts is a little scarey.
The problem with the RM is that the exhaust port is too small and the transfers are too big. When I port those cylinders I widen and raise the exhaust and epoxy-fill areas of the transfers to reduce their width. I won't cut the cylinder base more than .6mm, any material taken off the cylinder base must be trimmed off the sleeve and increase the recess in the head.
All this stuff is listed in my book along with other tips on jetting and aftermarket accessories.

 

[Hucker]

Thanks for the reply Eric. I sent you a email, but I'm not sure if you recieved it.