Topic: Motor turns, but not all the way.

[Six]

Hello, just added a 2nd bike - a '78 K with 16,000 miles.  It was cheap because it wouldn't kick over.  I got it home, squirted some Kroil down the plug holes and let it soak for a week.  Yesterday, I took the ignition cover off and put a wrench on it.  It TURNED, but not 360d.  I put a wire down the plug hole and can feel the pistons moving up and down, but after it goes over 3/4 of a crank turn it stops.  Is it a dropped valve? a broken cam chain? are there any other ways to check while the motor is in the bike?

Six - Minneapolis.

[MRieck]

You'll have to pull the valve caps off to check and see if the valve train is moving.

[Sandcast 2356]

Could be all those things, however, My brother and I unstuck a CB900 the other day, let it soak overnight in diesel. turned it back n forth for a long long time (couple of hors) before it would go all the way around. Sticking it in 5th and rocking helps sometimes as well.

[Six]

Well, it works NOW! - I removed the valve caps, sprayed a little penetrating oil, and rocked the crank back and forth for less than one minute, and I could feel it budging a little each time until she went all the way around!.  I think a valve was temporarily stuck from the bike sitting indoors a few years.   

So the lesson is: if the bike is not running, and the current owner doesn't know much about bikes - one can get a hell of a deal if one is willing to try a little elbow grease.

Thank you all for your great suggestions!
Six - Minneapolis

[kghost]

Marvel Mystery Oil.

Some down the plug holes.
Little in the Gas,
Little in the oil
You do the hooky pokey
And you shake it all about

[mcpuffett]

hey six,you got it running yet? mick.

[n9viw]

It's great that you got it, but just a note for next time: don't try to crank over the engine with the IGNITION side of the crank! The aluminum nut on the end of the crank will shear right off.