How to Unseize an Engine-My method

[gaillarry]

Got an 81 GS750E for free, with 12,841 kms, in mint shape. Bike was sitting in a shed for years.

Cleaned the carbs, fluids changed but the starter wouldn't turn the engine over. Suspected a stuck piston/rings. Put a wrench on the crank (left side) and the engine was stuck. I was tempted to use an impact gun but decided to soak the pistons.

I used "Engine Release" at $20 a can, not cheap but worth a try.

http://www.seized-engine.com/

After 4 days of soaking down the spark plug holes the stuff began to drain past the rings. I filled each spark plug hole with oil and I can now turn the engine over with a wrench.

Going to do a compression test hopefully all goes well !!

[Steve]

Don't forget to change the oil before doing the compression test, and you really should have used the 19mm nut on the RIGHT end of the crank.

Just to be sure, the LEFT side of the engine (and #1 cylinder) is under your CLUTCH HAND.
The RIGHT side of the engine (and #4 cylinder) is under your THROTTLE HAND.

And always rotate the crank FORWARD, which would be clockwise.

.

[Rover]

What happens if you turn the engine counter-clockwise?

[Steve]

You put strain on the cam chain tensioner that it was not designed to handle.

If you are lucky, nothing will happen. If you are not, ...

Actually, turning it small amounts, like backing up a bit to align a timing mark are OK, it's larger amounts, or trying to break free stuck pistons that will cause problems.

.

[Agemax]

Don't forget to change the oil before doing the compression test, and you really should have used the 19mm nut on the RIGHT end of the crank.

Just to be sure, the LEFT side of the engine (and #1 cylinder) is under your CLUTCH HAND.
The RIGHT side of the engine (and #4 cylinder) is under your THROTTLE HAND.

And always rotate the crank FORWARD, which would be clockwise.

.

or anticlockwise IF he is turning it by the flywheel on the left!

[Steve]

or anticlockwise IF he is turning it by the flywheel on the left!

Age, you are just trying to cause problems, aren't you?

The recommendation was to use the RIGHT end of the crank, therefore CLOCKWISE.

You keep that stuff up, we are going to have to insist that Max does the posting.

.

[Agemax]

Age, you are just trying to cause problems, aren't you?

The recommendation was to use the RIGHT end of the crank, therefore CLOCKWISE.

You keep that stuff up, we are going to have to insist that Max does the posting.

.

lol, i only said that because he DID say he turned the engine over from the left side.......

[gaillarry]

I used the left side (counter-clockwise) but the stator bolt started to come loose so I used the right side (clockwise).

The oil is draining now !!

[Steve]

I used the left side (counter-clockwise) but the stator bolt started to come loose so I used the right side (clockwise).

That is exactly why you should use the right side.

.

[Agemax]

I used the left side (counter-clockwise) but the stator bolt started to come loose so I used the right side (clockwise).

The oil is draining now !!

there, so i was right Steve........

yep, turning the engine by the left side is not a good idea. make sure you apply a bit of thread lock to that bolt and torque it up correctly when refitting it.
you dont want that coming loose again!

[Nessism]

Many times you will find internal damage on the cylinder walls and/or rings after extended storage. The rings often stick in the piston groove too, but will loosen up after a hundred miles or so. I'd forgo the compression test, or at least go in knowing that the readings may not be indicative of the engines true condition. Compression tests need a warm engine anyway, so either way you need to get the engine running before you judge.

[spyug]

Ed makes a very good point guys. Once the engine is freed up and you get it to run, use it a bit before testing for compression or your results may not be accurate.

A few years back, I had to take the head off my 750 Kat engine to free up seized rings. I tried all of the liquid products but nothing worked. A sharp rap on the piston tops with a piece of wood did the job. After lightly honing the cylinder walls and reassembling, I fired up and checked compression (after getting the engine to temp) and was dissapointed to only average around 120 psi. After running the engine 4 or 5 more times I rechecked and everything came up to around 150psi.

As mentioned, if and when you do use these liquids, be sure to drain and replace the oil and filter before running the mill.

Good luck and thanks for sharing.

Spyug

[gaillarry]

Here's the results from the compression test with WOT:

#1 65 lbs
#2 80 lbs
#3 70 lbs
#4 80 lbs

with oil down the cyls

#1 110 lbs
#2 120 lbs
#3 165 lbs
#4 185 lbs

I'll try to start the bike and see what happens but I suspect a top end rebuild is required.

[Nessism]

Low compression is to be expected. What you don't know is how much it will increase after some miles, and if there is cylinder wall and/or ring damage.

Needless to say, you should adjust the valves before trying to start the engine. Valve neglect is very common and you shouldn't run the engine if the valves are too tight.

[Sadsak]

I'm always leery of trying to turn a stuck engine with a wrench on the crank. There is always a risk of breaking a bolt off with extremely unpleasant consequences. My preferred method is to put the bike in top gear and GENTLY rock the bike back and forth. Quite often siezed parts will respond to a gentle impact as opposed to steady force. Just my 2cents worth, although with us doing away with the penny maybe it's a nickel's worth.