Vintage Dirt Bike Q & A

I bought a 75-76 cr250 nos gp cylinder to install on my 75 mt250. I later was told only the cr250 cylinders from 73-74 will fit any of the mt 250s is this true? If this is the case would I be able to use the bottom end from a 76 mr250 and the top end from a 76 cr250 and install it all in my 75 mt250? I have also been told that the aftermarket pipes for the cr250 73-74 will work if I weld a braket on the frame. I bought this pipe from ebay anyone know anything about it?
http://cgi.ebay.com/ebaymotors/ws/eBayI ... 0174572187
I guess what i am trying to find out is if I am gonna have to find a 75-76 cr250 bottom to go with my top or will somthing else work and also if its even gonna bolt into the mt250 frame. Thanks in advance for all your help I just hate buying stuff I cant use. Whats a nos gp cylinder usaly worth?

The 76 Cr cylinder will bolt right up to the MR bottom end. I'm running a CR cylinder on my MR right now and it works fine. The exhaust, though, might be more troublesome. I don't think your MT pipe will fit on a CR cylinder (but I'm sometimes wrong--don't tell my wife). But even if it will fit, you'll be losing some of your newfound power by putting that restrictive pipe on a CR top end. And you might also run into some routing problems trying to use the 75-76 CR or MR pipe on the MT frame. You can make a hangar, but I'm not familiar enough with the MT's sidepanel, airbox or rear fender to know if it would work or not. you'll have to use a 75-76 head on the cylinder if you try to use a CR pipe, because the head has the cutaway for the over-the-head pipe.

Well there is an mr250 engine on ebay I am going to bid on. The pipe sounds like it might be a problem so I was thinking the 73-74 dg pipes were under the foot peg and will work with the mt250 ive seen it done. So does anyone know if the dg pipe will work on the 75-76 cr cylinder kinda looks like it but im not sure. I just dont think I could fit the cr pipe to the mt.

Ok people I apologize for being so stupid I finally see the pipe on the 75-76 does exit on the oposite side as the 73-74 so the dg pipe wont work. So I guess I will just sell my 75-76 cr250 gp cylinder and keep looking for a 73-74 cylinder. Well unless anyone here has ever used a cr250 pipe from 75-76 on a 75 mt250.

I have a MR250 Engine on ebay now and all the other parts will be listed in the next couple of weeks, I have the whole bike minus the kick-starter, shocks, fenders, side panels, otherwise complete if there is something you need.
eddy20