leaky bottom end gasket on a '83 250r (AIR-COOLED)

[johns'85 250sx]

HI, I got a '83 250r (AIR-COOLED) and it has a possible (I don't know) leak from the bottom end any advice on how to fix it? BTW: the PO swapped bottom ends a while ago the old bottom end had a oil-cooler setup(that the orig. owner put on) , but he wanted it orig. so he swapped it back, but forgot to remove the old oil-cooler(which I did today) , so it has what I believe is a factory bottom end so anyways if you know what's wrong and how to fix it any help will be appreciated[IMG][/IMG]

[dcreel]

If the bore and the piston are in good shape, pull the cylinder head, then pull the jug. Replace the gaskets, torque to spec. If bore and piston are unknown, pull them have the cylinder bored to next oversize. Replace piston and rings with next oversize, and gaskets.

I'd start with giving it a bath though. Pulling a nasty dirty motor apart is never a good idea. You will get dirt into the bottom end.

Got any pictures of the oil cooler? On a 2 stroke, the bottom end oil just cushions the transmission from wear and shock. I don't know why somebody would put an oil cooler on a 2 stroke. Remember, you will need to plug the holes that were run to the cooler, if there are holes.

[johns'85 250sx]

as i said the PO swapped the bottom end back to factory after the orig. owner made it oil cooled, the oil-cooler looks just like the radiator on my old '85 (I think) Cr-80 2-wheeler only with a dipstick on top instead of a radiator cap, the thing was minus the hoses unfortunately, and he custom fabbed the expansion chamber to go under the thing, so well I drag out the pressure washer,tear into the engine I will order a whole new exhaust setup,and air filter box lid, thanks!

[Red Rider]

I see why the previous owner swapped the original bottom end back in & gave up on the oil cooler idea, as there is no easy way to "pump & circulate" the transmission oil up to a oil cooler on a 2-stroke.

[Motorious]

The plot thickens. Well, that would explain why you mistook it for a watercooled motor in your other thread. As Artie Johnson used to say on the old Laugh-In TV show, "Verrry interesting".

You should continue this thread on this project trike with more (and better ) pictures. I know a lot of us would get a kick out of witnessing the process of fixing this first generation, uniquely modified (never heard of a 2 stroke with an oil cooler before) 250R. I know I'd love to see the mods the original owner did to the motor.

Good luck fixing her.

BTW I got an '82 250R I paid $100 for and is damn near a basket case (check my signature)...hoping to do a frame-off restoration to it this winter if I have the funds.

[harryredtrike]

bring that trike to a car wash and clean her up,then go through the carb,bearings,controls,and fuel system to see whats good and not good.and go from there.make a parts list of want to have's and got to have's and start your project.good luck and use a manual

[cr480r]

hit it with some degreaser and wash it clean.. then remove the carb and exhaust... then pull the head and cylinder... A blown base gasket is a great reason to do a much needed top end inspection. And a perfect time to re-ring or replace the piston if needed.. An inspection is always a good idea on a newly aquired used machine.. gives you a chance to find bad components before they pose a problem, plus you'll know what you have as well as a basis for comparison later on.. a compression check and leak down test is also a good idea