Vintage Dirt Bike Q & A

A year or so ago I bought an '74 MT125 to restore.

Finally got to it last week and noticed that the motor did not have the oil injector pump or the hole for the revcounter cable.

The engine number starts with CR125M. Is this likely to be a CR125 motor. Were they known to be interchangable? (When I first got it I thought it had a pretty snappy powerband!)

The MTs had their own model ID and serial numbers so definately a CR engine.

CR Serial Guide
http://www.honda-elsinore.com/elsieref/ ... .php?t=578

MR Serial Guide
http://www.honda-elsinore.com/elsieref/ ... .php?t=579

MT Serial Guide
http://www.honda-elsinore.com/elsieref/ ... .php?t=580

Thanks!..It has a decompression valve/insert on the head as well as the plug (hole)..did the original CR heads have this or was this a feature of the MT?

I only have 250s but those do have the two threaded holes. One comes from the factory with a bolt/plug in it vs. something you can use.

On a stripped down MT I keep for dirt riding I use a spark plug in the 2nd hole just incase the other one fouls. Never happened but I am ready if it does. I think some of the old CZs actually ran dual coils and just fired both plugs but I am not an expert on CZs, just have a vintage manual that I read through.

thanks ricortes

My two '74 CR125M's do not have a secondary plug hole for a compression release in the head. If your head does and it has a CR motor number, perhaps you have an MT head and possibly cylinder on a CR bottom end. Just speculating on this since I don't own an MT125.

There are a couple of good close-ups of a CR125 motor on the Bike of the Month page at http://www.honda-elsinore.com