Vintage Dirt Bike Q & A

Hey guys I'm looking to pick up a Honda MT125. The plan is to keep it passably street legal but trick it out with some CR goodies and a full red paint job. I'd like to get as much power out of the motor as possible. Would a MR175 cylinder bolt on by any chance. Even if I had to have the cases machined that would be OK.
If thats not a possibility, what are suggestions for beefing up the stock motor? I have several CR125 motors, but need to at least keep the MT center cases, so the motor numbers will match for registration purposes.

Thanks

The MR cylinder will bolt up , but the cases will need machining to take the larger sleeve . It will fit straight onto the 76-78 CR cases so if you have those , you can use for measurements.
The snag is you need the MR crank / rod , which is the same stroke as the 125 , but longer and with larger bearings due to the heftier piston
Might be easier to use a CR top end and ignition (if you don’t need lights) the CR 6speed will also fit in the cases