No Compression

I just changed the head gasket on my 1982 XJ650RJ, Seca.

The first time i put it back together, I had a chirping sound, from what I read here and heard from others, it was probably a leak somewhere.

I pulled the head off again tonight and started over again. Saw no damage anywhere. checked the valves, turnng the engine over first by wrench, then with the starter, no more chirping sound.

Put the cabs on and the exhaust, tried to start it. No fuel being drawin into the plug.

Tested the compression, NO COMPRESSION.

My cams were lined up with the small dot to the arrow on the center cap. My first cylinder was TDC, the indicator on the end of the crankcase was lined up with the T

Any ideas or suggestions

Thanks

Ken
Montreal

 

Check the valve clearances; maybe you've got one being held open.

Either that or the head and/or cylinder block isn't flat anymore and needs machine shop attention.

Did you check the "flatness" of the head and cylinder deck before putting it back together?

OR-

You're 360 out on your cam timing. Remember each piston hits TDC twice in a "cycle."

 

Are you sure the cam chain is on the crank sprocket? There is enough room for the chain to for it to ride right next to the sprocket. I have had that problem before and ended up with some bent valves. Lets hope that did not happen.

 

I did check the valve clearances last night as I put it back together. They are all within spec.

I did not check the head for flatness.

I had the bike running the night before with these gaskets, but was getting a strange chirping sound. Now no chirping, but no compression.

The cam chain is in the sprockets. I checked that.

How can I be 360 degree out, I understand 180, but 360? How do I fix that.

Going to rotate the motor til the T lines up, then remove carbs, tensioner, sprockets, rotate the motor through one cycle, til No. 1 is TDC, check camshaft alignment, if out of whack, remove caps and realign, install caps, sprockets and tensioner, check for compression.

Scratching my head

Ken
Montreal


[/quote]You're 360 out on your cam timing. Remember each piston hits TDC twice in a "cycle."[/quote]

 

The pistons hit TDC on their compression stroke (both valves closed) AND (one full crankshaft revolution later) on their exhaust stroke.

NO compression at ALL? In any pot? It has to be cam timing, nothing else would explain it. All 4 pistons didn't suddenly develop holes.

 

Success. It was the cams. Went back rechecked everything, aligned the cams again. Compression was there. Closed it up, started right up, just like before.

17 hours to change the head gasket.

Thanks to all for the assist.

Off to the cottage for the rest of our long weekend. Horsehoes & BBQ. Wahooooooooo.

Ken
Montreal

 

17 hrs.........I think you set a new record. LOL

Dave F