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Author Topic: Engine Seized?  (Read 1306 times)

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Offline Kirby

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Engine Seized?
« on: August 06, 2009, 06:00:13 PM »
New guy, first post.  I inherited a freebie '72 CB500.  Most parts are there, looks like a straight frame and forks.  Has not been turned over in probably 8 years, and sat outside under a tarp.  I cannot get the engine to turn over...therefore, cannot rotate the camshaft to get it out, so cannot remove the head.  Is there any majic oil to put in the cylinders that will help free up the pistons/rings?  If I cannot get it to rotate will Ihave to cut the cam chain to be able to dismantle the engine?  Engine is now out of frame on the workbench.  Ideas please.  Thanks, Kirby, Marshall, VA
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Offline razor02097

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Re: Engine Seized?
« Reply #1 on: August 06, 2009, 06:30:59 PM »
PB blaster is good stuff.  I have also heard of mixing ATF and kerosene works well as a penetrating lube.
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Offline 1974CB750rider

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Re: Engine Seized?
« Reply #2 on: August 06, 2009, 07:24:29 PM »
I prescribe PB Blaster in each spark plug hole 2 times a day for a least a week. It may take 2 weeks.
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Offline ekpent

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Re: Engine Seized?
« Reply #3 on: August 06, 2009, 09:40:53 PM »
Read and re-read all the posts while all the goodies you put down the holes soak in.Be patient and let the chemicals do their job and see how the boys broke'em loose.Would have been better though if it was still in the frame and you could have let the rear wheel help you out. Did you see any water-rust when you drained oil??
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Offline Gordon

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Re: Engine Seized?
« Reply #4 on: August 06, 2009, 09:52:04 PM »
IIRC, TwoTired posted the results of a test of penetrating lubricants in the past year or so.  It may be in the Tricks&Tips section.  Regardless, the winner was a mix of ATF and acetone. 
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Offline Patrick

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Re: Engine Seized?
« Reply #5 on: August 06, 2009, 09:59:51 PM »
You are going to to be far better off tearing down that engine if you get the pistons to move before you start. I've torn down frozen engines and it was a biatch. Prying a cylinder block from rust frozen pistons is not for the faint of heart....

Patrick
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Offline coldright

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Re: Engine Seized?
« Reply #6 on: August 06, 2009, 10:21:54 PM »
Read the first post on this thread... it was the first step in getting my "seized" bike on the road...

http://forums.sohc4.net/index.php?topic=51874.msg559014#msg559014
« Last Edit: August 06, 2009, 10:58:05 PM by coldright »
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Offline Gordon

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Re: Engine Seized?
« Reply #7 on: August 06, 2009, 11:01:47 PM »
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Offline Kirby

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Re: Engine Seized?
« Reply #8 on: August 07, 2009, 11:42:39 AM »
Thanks for all the replies...the oil looked fine when I drained it, no water/rust.  I put PB Blaster in several days ago, will do some more and give it a week while I do more research...I also have plenty of kerosene and acetone.  The engine looks decent otherwise.  I am suprised to see the camshaft has no bearings...the manual says if there are scratches in the lands where the shaft rotates, just replace the head!  Easy for them to say.  Also, could the carb linkage be any more complex?  I'm sure I'll have more questions later.  Thanks again, Kirby
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