engine won't crank manually

All great info, much appreciated! Any suggestions on reputable sites I can get rebuild supplies from if necessary?

 

50/50 mix of Acetone/ATF fluid is the best method to release seized pistons or anything else seized.

 

POST #15 is the MOST important post on this thread.

"Last summer I was able to manually rotate it, so maybe like you suggested after some kerosene....."

Think about this statement.
Sounds like all this engine needs is a dinggleberry hone job, and a set of rings and you will be in business.

You are going to be done very soon.
Don't let the cam chains completely loose in the case. Tie a little piece of wire through the cam chain and keep it held up so it does not get bunched up in the bottom of the case.
Just get the workshop manual and take those heads apart as the manual says.
MAKE SURE you have the engine on #1 cylinder, TDC when reassembling the engine.

 

Can we see a photo of the engine? Sitting on a bench or something?

 

These are some photos taken by my fiance. I'm at school right now so this has been a weekend project. Let me know if additional photos are needed.

Lucas

 

Before I dig into this engine, I wanted to add a new finding that might help figure out what is going on. The rotor turns freely but only part way, about 180 degrees instead of fully around. Is this normal or does it point to something more specific?

Lucas

 

Thanks for the photos.
You say it turns 180º does it feel like it just gets tight or does it feel like it is hitting something?
It is not normal for an engine to just turn part way around. Are you turning it with the spark plugs OUT??

Also since the carbs are off - LOOK down into the intakes and see if the valves are all there and if some are open and some are closed.
You should be able to see the valves with a light.

Make sure you are turning the engine the normal direction of rotation. NOT backwards.


GO BACK TO post #15 of this thread. Think hard if you were able to turn it all the way around at that time.

 

I am almost positive I was able to turn the engine all the way around. Right now, I am turning it in forward motion, so I guess that would be counter clockwise. It gets the the point where it loosens the rotor bolt, like it just stops and will not budge without loosening that bolt. Transmission is in neutral this whole time. Spark plugs are out. The valves are all there, and they all appear to be closed. I'm gathering this from the fact that I can see pooled up PB plaster/wd-40. There is some oxidation on the valves, so I don't know if this is what is causing the stuck engine.

On a side note, when attempting to remove the bolts on the cover over the camchain, the head on the last one ripped a little and is making it difficult to get a tight fit for the proper sized socket. Any suggestions? Thanks.

Lucas

 

I think that normal rotation for that engine is clockwise NOT
counter clockwise but there should be a arrow on the face of the rotor.

The other way you can tell is to put the engine in gear(1st or 2nd) and turn the engine, and the counter shaft sprocket should COUNTER CLOCKWISE.

The third way to tell about the rotation is look at the timing marks. There is TDC and the advance mark for the timing light. The TDC should come LAST. The engine fires slightly Before TDC.

The fact the rotor bolt is loosening means you are turning it the wrong way,
but the WORKSHOP MANUAL will make it clear.

To do the work you are doing requires that you have the workshop manual
so you do not cause more damage than there was in the first place.

Just like a doctor has to remember to "do no harm."


It is normal during tear down of an engine to have bolts get messed up EVEN when using
the proper tool. Just remember to be professional and replace buggered up fasteners when putting the engine back together.
Just like wiping off greasy hand prints and keeping seats clean. Etc.,.

 

If you have a bolt that won't loosen take a metal bar or hammer and
tap the bolt first a few times and many times that WILL make it come undone.

It breaks the molecular bond.

 

Just an update on this. I got the bolt unstuck securing the camshaft chain cover/oil line. My next step would be to continue with the shop manual to get the heads off so i can further investigate this engine. The only problem is, the shop manual says I need to rotate the rotor to a certain point that allows access to the bolts that secure the camshaft sprockets. After a week of the engine sitting and trying to let the WD-40/Pb-blaster do their job, the rotor is still in the same situation; that is, I can't rotate it fully, but only about 180 degrees in either direction. Any suggestions on getting the camshaft sprocket off without having to rotate the rotor? Thanks!

Lucas

 

Question is this: can you still turn engine partially around but not all the way ??

If you can turn it at all, rings/pistons are NOT stuck, and you have a different problem.

 

Listen to the the squirrelman, if you can move that crank at all and it stops you have another problem all be it a serious one.

 

If the engine will turn 180º in each direction that make 360º.
Can you see the bolts holding the cam sprocket?
If so... then it is a matter of CAN YOU GET TO THEM ?
They are probably 10mm
If you cannot get to them then you will have to remove the cam chain by undoing the cam chain.
You can remove a pin in the chain or CAREFULLY grind one of the pins and push the pin out. Then remove the cam chain, that way you can turn the cam and get the bolts out. After you undo the cam chain DO NOT TRY TO TURN THE ENGINE AT ALL!!.

 

First question, will removing a pin require me getting a new camchain? Second question, I can get to the bolts but there is not enough clearance on one of them to fully remove them from the sprocket. I got both bolts off from the sprocket for the intake cam, and when trying to rotate that cam by hand same problem as before, it won't rotate fully, so maybe this is a cam problem?? All the help is much appreciated!

Lucas

 

If the cam will not rotate with the chain connected it DOES NOT mean there is a problem with the cam.
If the chain is OFF and the cam will not turn It just means a piston could be contacting a valve and if you put ANY PRESSURE on it the valve will be bent
and the engine will never run right.

If you remove the pin from the cam chain by grinding the pin you will have to replace the cam chain but it is probably worn out anyway or stretched. anyway so do not worry about it.

But do not try to turn the engine AT ALL once the cam chain is off.
But then you can take the cylinder head off.

Also VERY
imPORTANT!!! When BEFORE- you take the pin out of the cam chain, tie
a wire through each end so that the ends both do not fall to the bottom of the case.

 

If the cam will not rotate with the chain connected it DOES NOT mean there is a problem with the cam.
If the chain is OFF and the cam will not turn It just means a piston could be contacting a valve and if you put ANY PRESSURE on it the valve will be bent
and the engine will never run right.

If you remove the pin from the cam chain by grinding the pin you will have to replace the cam chain but it is probably worn out anyway or stretched. anyway so do not worry about it.

But do not try to turn the engine AT ALL once the cam chain is off.
But then you can take the cylinder head off.

Also VERY
imPORTANT!!! When BEFORE- you take the pin out of the cam chain, tie
a wire through each end so that the ends both do not fall to the bottom of the case.

 

Is it necessary to get the camshaft sprocket off before i remove the heads? The shop manual seems to be leading me in that direction but I do not know if that is necessary. If so, I do not know how i will do this as one of the bolts holding the sprocket on is obstructed and I do not have the clearance to get it all the way off without rotating the cam, which will not move enough to allow that. Thanks.

Lucas

 

It may be able to get the cam chain off buy putting slack in it one of two ways.

#1. To do this you have to get/make a hook tool. You have to pull up, where red line is, and may also have to use a thin screw driver to move the pinch plate, blue line, in order to push the rod back to get slack. This is the tensioner in the rear part of the head. It's a little tricky getting to the pinch plate. A good light will help you see it. By pulling up you release the tensioner and the chain goes slack. Make your hook strong because you will be pulling against the tensioner bracket spring. Which wants to pull the arm down.

#2. You should be able to remove the four bolts that hold the tensioner bracket to the head. Which should give you the most slack available. Be careful because the bracket will be under tension some what and may want to pull the last thread or so with a bolt. Release what tension you can by moving the pinch plate and just pulling up on the arm.

You may be able to get enough slack to get the chain over the sprocket. I've never tried this myself. I did put in new tensioner bracket assemblies this winter and noticed a lot of slack just by releasing the tensioner without pulling up. Seemed that the rear pair of cylinders had more slack than the front.

Good luck.

 

This is definitely a valve issue it seems so clear now. Unfortunately, I had to remove the chains per Donald's instructions only to find out it wasn't totally necessary for what I was trying to do. Anyway, does anyone know if cam chains from either an 84 VF750 or 86 will fit my VF700?