Vintage Dirt Bike Q & A

Fellow Elsinorites:
I need more performance out of the MR175 engine in my 75 CR125 bike. Has anyone out there done any work on their MR175 engine?
Sounds crazy but I've grown to love the peaky powerband of the CR125 engine and would like something like that in the MR engine but 40% stonger for the extra 50cc.
Cylinder porting will be the key but also carb size, expansion chamber mods and ignition.
Any recommendations for who can do this type of porting?
Thx.
Mark

Here's my current incarnation of the 75 Elsinore. The 125 ignition really helps, as you already know! I adapted a 125 Elsinore pipe, which gives the engine much more punch, but the 175 just peaks at a lower rpm. (I did have to lengthen it to make it fit) I think the intake on the 175 is somewhat restrictive, as are the intake ports, but I have not touched them yet. If I get really ambitious, I'll try to mill an aluminum intake to accept a standard mikuni flange mount with a bigger mikuni. For now, my sons already beating me quite handily on it, so there's not much incentive on my part to make it faster. I did add 81 XR200 shocks, which give about 6 inches travel.

I don't know of anyone who would do porting on a 175 motor for you.

Thx
Hans