Vintage Dirt Bike Q & A

I picked up a titled (in parts) 76 MR250 last week from a buddy- the price was right - free. It has been sitting for ten years with a cracked piston. I have a couple of questions.

1. Is there a direct-fit boxed aluminum swingarm that will fit this bike?
2. I will ride this bike primarily on the road, so is there a secret to jetting the carb to accept a pod air filter? My GS650 never ran properly with the pods, even after the re-jet.
3. Does anybody know any good resources, reputable shops for engine rebuilds in the Seattle area?

I have the following things for sale too.
1. Two headlights (one case and one complete)
2. Front and rear fenders – white plastic in good shape.
3. Front forks – seems to have a slight bend in the one of them – not sure though.
4. Swingarm
5. Toolbox and tools.
6. Petrol tank with petcock
7. Front and rear tire assemblies; brakes, hubs and rubber. Rear rim is new but has surface rust on some spokes. Front rim has a slight tweak in the rim but still holds the bead.
8. Air box assembly
9. Side covers
10. The only thing I want to keep on the bike is the frame, engine and speedo.


I am most concerned with any information regarding the aforementioned questions and not concerned with making money off these used parts. Name a price and I probably will not turn you down.

FYI- I will send photos upon request. I prefer email to IM. mailto:Mr250@jackrabbitslap.com

Champion cycles is who does all my work I dont want to or cant do myself. An older guy by the name of rick does the work his number is 425-255-9602. He isnt in seattle but is in renton not horribly far away and he is very resonable.

Very nice - thanks. That's the beauty of Seattle, every burb isn't far away. Thanks again.

The MR has the same frame geometry as the 75-76 CR250. And while there are plenty of box aluminum swingarms I've seen for the 73-74 Crs, I've never ran across one for the 75-76 models. The offset is different, so a 73-74 will not work on the 75-76 or the MR. I am sure someone or some company probably made some at some time, I've never heard of one or seen it. Good luck with your project!
On your carb, the MR Keihins are a bit finicky to jet. They have three jets: pilot, main and power jet. You'll just have to experiment and do plug readings in an efford to get the jetting right. Since they run a bit rich to begin with, you might just be perfect as it sits after putting on a pod filter.

You gotta love forums... thanks for the input. Perhaps I will get a custom refab...? I dislike the stock swingarm.