Vintage Dirt Bike Q & A

How many of you have ran into different kickstart shaft assys? I have been building two CR250Ms for vintage racing (besides the one I restored to look at and not ride) and have came across three different ones so far. I had several bottom ends gathered over the years and have noticed differences in the clutch covers also. I have had to match the covers to the shafts to keep them from dragging or even fitting at all. Some of these covers had an oil check screw and some did not. These are all 73/74 models.

The clutch cover with the oil check bolt showed up in '75 on the M1 and had a "381" vs "357" part number. It is compatible with all 73/74s and the "357"
series kick shaft spindles. There are three kick shaft spindles. 28250-357-020 was specified for the 73/74 Ms. 28250-357-030 was specified for the M1s
and 28250-358-000 was specified for the '76 and supercedes the other two. All should be compatible.

Hope this helps.

dogger

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1973 CR250M
1979 CR250R
1993 CR250R
2008 CR500R
2009 CR250R

These were all M bottom ends, but the cover could have been replaced. One shaft would only work with a certain cover. If I used it with any other it would lock it up when the screws were tightened. Also, one had a spring that hooked in the clutch cover instead of the case. Probably a mix of MT, MR, and CR stuff. How's the CR250R cpming?

Good point, I didn't even think about that. A lot of those components will bolt on the CRs but don't necesarilly fit or function correctly.

The '79 has been slow going. I have completed the tank, seat, carb, front hub, and triple clamps. I have all the parts to rebuild the bottom end but still need to strip and powder coat the cases before I can proceed. I think this is going to be another lengthy resto. Here is a pic of my restored tank next to my color sample plastic - turned out nice.

Did you finish your "show" '73?

Have a good 4th.

dogger

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1973 CR250M
1979 CR250R
1993 CR250R
2008 CR500R
2009 CR250R

The "looker" is complete but if I come across better parts I put them on it. I bought a NOS ign cover I'm putting on it. I also found some new sprocket locks and a throttle cable to replace the Terry cable I put on it. The main thing I want to do is send the pipe to get the couple of dings taken out of it. This is the best pipe I've seen other than a new one and I wasn't going to do anything other than media blast and paint, but the rest of the bike came together so well I can't leave it undone. I found a foot brake pedal spring, but still need the spring on the front brake arm. It been sitting in the corner of the shop as I have been building these two racers. I am hoping to ride them this week. UPS tracking shows my cylinders I sent for porting arriving Monday and that's all I have been waiting on. My first vintage race should be Mid-Ohio at the end of the month. The tank looks good!