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1974 Kawasaki F11 250 oil injection

7K views 6 replies 6 participants last post by  Tom Schmitz 
#1 ·
I'm looking a a 1974 Kawasaki F11 250 as a winter project. Just got off the phone and he said that he thought the top end was seized up. He had just replaced the rings, fired it up and went for a short ride. Seems he got only about 3/4mile down the road when it quit running.
He tried kicking it over when it got real hard to kick over. He figures the rings seized to the cylinder, he has not removed the cylinder to inspect.

Question: This bike uses the oil injection system, no pre-mix of gas required. I am totally unfamiliar with the injection systems. Is this system pretty rock solid, cause it almost sounds like there was an issue with it when he took it for its break in ride, even though he said there was blue smoke from the exhaust pipe indicating that some amount of oil was getting in to the cylinder.

He's asking $300 for the bike, everything seems to be there except for blinkers. I'm not afraid to sink a few hundred bucks into a project bike, but if you guys tell me the oil systems on these things suck, well then i may reconsider.
thanks
 
#2 ·
Your call, but . . . a backup to the oil injection system is pre-mix . . .

Sounds like it could have suffered a thermal piston seizure (a possible consequence of inadequate lubrication, as in defective oil injection system).

Regardless, if required, re-ringing isn't that big a deal on two-strokes, if my memory serves. You may get by with a light cylinder honing.

Your call, and best of luck if you chance the rebuild/restoration!
 
#3 ·
basement,
Are piston and rings still AVAILABLE for that bike? Ask your Kawasaki dealer!

I might suggest, that the bottom rod bearing, Needed replacement WHEN HE replaced the piston and rings, ONLY! Improper air filter service will DO THAT, to a two stroke and INEXPERIANCED mechanics.

The cylinder is PLATED, as I remember. CAN BE re-plated. NO Kaw. oversizes. U.S. Chrome. IF you can rebuild the rest of it.
 
#4 ·
basement,
I made an error, Last Night. Based on currently AVAILABLE, parts system.

The 1973-1975 Kaw. F11 250 dual purpose bike did HAVE a cast iron cylinder liner. Re-boreable. I got to thinking about what I had said, I knew that wasn't correct.
Thanks to OLD paper parts books, and a pack-rat nature, I HAVE in stock, 1 each, 13029-055 .020" O.S. piston and 13025-030 .020" O.S. ring set.

But, If Bottom Rod Bearing is worn-out, it is probably a mute point, Oh Well.
NO Crankshaft parts in stock! Most NOT available from Kawa. either!
 
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#5 ·
Awesome bike. Make sure you bleed the injector system, I usually run premix and run the engine with the pump cover removed while looking at the clear oil lines for bubbles. If you see any, crack the fittings loose downstream to bleed. The oil injection is worth keeping but I put oil in the gas as well for a little insurance. Modern two stroke oil doesn't smoke much anyway. Be wary of just disabling the oil injection to make the bike more reliable as you will here many times. Some of them also lube the crank bearings , I don't recall off the top of my head if the F11 Does or not. The F11 is one of the few piston port engines Kawaski built, it really sings, also one of the first that handled decent. For the time anyway.
 
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