Antique 91 CR250 A few questions? Hope someone can help.

[mifun3]

Hey guys,

Well, bought a 91 Cr250 pretty cheap runs but needs alot of TLC.

I know it's an old bike and I don't want to make it new but just enough so its fairly tight and reliable.

Torn it apart last night, found a few major things to be fixed.

First, swingarm has a few cracks where the needle bearings and bushings are(probably could be welded but would perfer to replace), due to lack of maintenace. Now, is there any way that a 92+ swingarm can be fitted, (90 91) are rare!!

Next question, Tried to find a marking on piston for bore size but couldn't find one. I mesured the piston with a digital caliper Found a reading of 2,65 in or approx 67.3mm.

Can a 91 be bored? I checked wisco site and seemed to have found them saying it's nickel coated. Is that possible?

Cyl is in good shape no stuffs or markings, unless it's deformed I'll probably just give it a fine honing.

Thanks,

Mike

 

[TimberPig]

I doubt that a 92 swingarm will fit, as it was a new chassis and motor from the 91.

The cylinder is indeed Nikasil plated, and cannot be bored without sleeving or replating. If it is in good shape, then just get a new piston rings, and bearing kit, set it in with the right piston to cylinder clearance and ring gap and run it. The easiest way to do this, is to have a shop measure your cylinder, and order you the correct piston kit, then check the tolerances when installing.

That bike is older, but it is far from antique. It still offers reasonable performance for a relatively cheap price. The suspension was a little rough, but could easily be improved if you chose to invest a little money into it. If you chose to do this, you would have to keep the bike for a bit, as performance modifications like this don't really increase the value of the bike.