MTX125 upgrade

FFMan · Derestricted Danger Joined: 29 Apr 2015 Karma :

Does anyone know is the difference between the MTX125 and MTX200 just the top end & atacs.

In other words, could a piston, barrel & head etc be transplanted over. Is the rod a different length maybe ?

I am guessing the exhausts are different too, the 200 I guess had a bigger expansion chamber etc.

Is it likely the 2 stroke oil pumps were different ?

any comments appreciated.

Acerman · Banned Joined: 26 May 2015 Karma :

They have different bore X stroke, so no its not a swap here.

FFMan · Derestricted Danger Joined: 29 Apr 2015 Karma :

ok thanks for the info

stirlinggaz · World Chat Champion Joined: 22 Jul 2007 Karma :

Hi,
although you cant just plonk a 200 top end onto a 125 bottom end, you can just slot the 200 engine straight in.
good luck finding one though.
the 200 uses a bigger carb which is probably relatively easy to find but you would need the 200's expansion chamber & these are like rocking horse sh*t. How do I know? I still have one in my garage.
forgot to give it to the buyer of my old mtx 125/200. Guy thought it was xmas when I gave him a big box of spares (Including a 125 motor & a 200 motor, spare atac assembly, carb etc)
kinda regret that now..

cheers,
GAZ

stevo as b4 · World Chat Champion Joined: 17 Jul 2003 Karma :

As you say the carb is no biggie, there's probably plenty of other carbs that can be made to fit the std reedblock stub.

And these days I wouldn't worry about the exhaust either. There's lots of firms that can make a suitable pipe to work well with the 200cc motor if your happy to splash the cash on a custom pipe. I also believe that some people have used pipes from other 200cc bikes and adapted (cut&welded) them to fit the MTX200.

The hard thing here is going to be finding an engine, and then if you do the parts to re-build it. MTX200 pistons seem to be rare now, as they were once a part of a popular tuning upgrade for the Lambretta scooters.