Vintage Dirt Bike Q & A

Hi guys-what useful parts are in a 73-74 mt250 motor that can be used in a 73-74 cr250 motor. thanks in advance.

The kickstart gear out of the 74 MT250 will swap with the kickstar gear out of the 73-74 CR250 & they use the same part number. The 73-74 CR250 kickstart gears get alot of abuse!

In a similar vein I just gave away a MR 250 engine to one of the youngsters on my fire department. Was there anything usefull for my CR in there? (I can always plead for a few parts back if so. And if he doesn't comply he'll be waxing engines, scrubbing floors and cleaning fire hose the rest of his career. )

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Those who can make you believe absurdities can make you commit atrocities.

Loren Davis
51y

Hey , I like your sense of humor and appreciate the information- I tried selling the mt motor on ebay and did'nt have a single hit. And moving forward I am trying to not packrat everything for a rainy day. So I guess the bottom line is that I might as well give it away and move on- Thanks

Hey HRL,

I bought the motor on Ebay several years ago while in some sort of mental fog I guess. And a heavy fog at that. Was actually thinking MT even though the ad clearly said MR. Price was cheap... guess that's why. My bad.

Hang on to those kick starter gears. They're like hens teeth only harder to find. If you are going to sell it, with those gears, let me know. A buddy of mine needs them.

Cheers

_________________
Those who can make you believe absurdities can make you commit atrocities.

Loren Davis
51y

The MT250 motor is good for more than just the kicker gear. The clutch cover is the same. If the rod is good it will swap with the CR but not the whole crank. I used an MT rod with new bearings installed on one of my CR250 motors since the MT250 rods never seem nearly as worn as the CRs. You can also use the 2nd gear (female only) since it is the same gear as the CR250. The clutch will work if you use the matching gear off the MT crank although it rides on bushing not bearing like the CR. The shift shaft is the same. I believe the shift forks will swap also. I once used the entire tranny out of an MT250 in my CR250 cases but I had to have the output shaft turned down to fit through the smaller CR output shaft bearing. It worked but the ratios are spread out a little more so shift from 2nd to 3rd caused a slight lag. Hope this helps.

the pressure plate and cluch hub to. the manual say that they only diffrence in the transmission is the ratio.

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W.F.O. All the way!

The entire top end [piston, cylinder, head, ...] can be swapped but the question would be why. If I have it right most people go the other way, put the CR parts on an MT for a performance increase.

That being said I may put an MT engine in my 74CR. I want to ride it an haven't been able to find an engine. I am a low performance rider so I don't need a high performance engine.

I also have both a 76 CR250 and MR250 with a couple of MR250 spare engines. The 76 CR came with a really busted up engine, bolt dropped down the intake and smashed up cylinder and crank case. Working on my aluminum welding skills right now. Haven't split the cases on the MRs yet but the top ends appear to be identical. Cranks are diff, small shaft for the CR magneto while the MR has a huge set up for running lights.