Number 2 cylinder is lean

[KA1J]

I found out the reason for the lean #2 anyway; the PO or one of his ilk neglected to put the exhaust gasket in #2 cylinder when he installed the pipes...

Man I hope the valves weren't damaged.

I've got zero compression on #2 cylinder. I was checking the valve shim readings and by chance I put my thumb over the spark plug hole and turned the crank, there was no pressure coming from the hole. Put oil in the cylinder and it didn't help. Looks like the exhaust valve is shot. All the things I've found wrong with this bike because of the PO that I've had to fix.

Now I have to remove the head and deal with this. Where will it end...

Criminy. Yeah I'm whining, I've put so many hours in finding needed parts for this XJ1100, undoing the damage the PO did & never told me about that I had to keep finding and all I keep doing is finding more and more problems, each seemingly more severe than the one before. Nobody I know at all around here to help me with what I'm doing. I am so grateful for the forum!

Maybe I can just find a good used head & swap it.

Lovely. Just lovely...

[petejw]

did u turn the engine over by the starter to check compression?

was just looking at the spark plugs u pictured, bit hard to see
but the 2nd plug, the gap looks huge,
what gaps have u got the plugs set at?

also a missing exhaust gasket wouldnt make that cylinder run lean either
but a large plug gap could cause the cylinder not to fire.

how did u end up going with he valve clearances?

[KA1J]

Hi Pete

No, I didn't use the starter, I'd been checking the shims and removed the plugs. All the cylinders generate lots of pressure when I turn the crank except #2 which has zip for any pop whatsoever. The valve clearances for #2 is exhaust .008 and .004 for intake. This was read at TDC.

The gaps were the same as when they came out of the box & I measured them at the time. I've got the green Dynacoils so they'll spark over that gap but I didn't know there was any issue with compression till today.

[KA1J]

In case I need to replace the head, will any of the XS11 heads fit the XJ11 without modifications? I looked on the cross reference & it had the XJ1100 only under the part number but I thought that other than the electrical system & advance, the engines in the XS11 & XJ11 were the same.

[SFerinTEXAS]

The valve clearances for #2 is exhaust .008 and .004 for intake. This was read at TDC.

never seen a valve clearance measurement referred to in such a way. Heck, Ive never looked at the timing position at all when checking valves

[motoman]

Possible collapsed rings in #2 from excessive heat aside from possible valve damage.......JAT

[SFerinTEXAS]

If you really have no compression in that cyl its also a possibility you have a hole in the piston or a separated crown.The former you may can see thru the plug hole, the later could certainly be seen.If its a burned exhaust valve you should feel it exhausting on the compression stroke with the pipes off

http://www.xs11.com/forum/showthread...=melted+piston
http://www.xs11.com/forum/showthread...=melted+piston

[KA1J]

never seen a valve clearance measurement referred to in such a way. Heck, Ive never looked at the timing position at all when checking valves

I got the value from the service manual where it said:
Exhaust Valve clearance (cold) .021~ .025 mm (.008 ~.010 in)
intake Valve Clearance (cold) .11 ~ .15 mm (.004 ~ ,006 in)

My feelers are in mm & inches. It was suggested I take the valve measurements at TDC on a given cylinder to be mechanically at the place where the gap would be maximum.

It was then I tried putting my thumb over the spark plug hole & found no pressure.

[KA1J]

Possible collapsed rings in #2 from excessive heat aside from possible valve damage.......JAT

That would be pretty ugly. I'll have to remove the head and I guess I'd look for scoring on the piston sleeve/walls? Not sure what JAT means?

This all is coming at a difficult time, Mom passed on this Monday and I'd been looking forward to having this restoration done by the middle of next week and then getting away and taking a long ride.

[KA1J]

If you really have no compression in that cyl its also a possibility you have a hole in the piston or a separated crown.The former you may can see thru the plug hole, the later could certainly be seen.If its a burned exhaust valve you should feel it exhausting on the compression stroke with the pipes off

http://www.xs11.com/forum/showthread...=melted+piston
http://www.xs11.com/forum/showthread...=melted+piston

I looked inside with a bright light and did not see any apparent hole showing. As it looked in the top photo, the hole would be pretty much in the middle, directly where the plug would insert? If that's where it would be, then no, I see no hole. I probed with a thick wire & didn't feel an unexpected pit

The pipes are off so I'm going to try & see if I feel any leakage from the port on exhaust. Will try anyway. Will probably have to put tape on the outlet & see if it pops off, I'm one-handing this bike and don't have an extra hand to help watch/move things.

And thank you all for the suggestions!

[crazy steve]

Easiest way to check for a burned valve is to get that cylinder up on TDC with both valves closed, then pull the spark plug and put some compressed air into the plug hole. If air comes out either port, there's the problem...

[KA1J]

Easiest way to check for a burned valve is to get that cylinder up on TDC with both valves closed, then pull the spark plug and put some compressed air into the plug hole. If air comes out either port, there's the problem...

Hi Steve,

I don't have any way to do that.

Oh I could figure something with JB weld & an old hand operated tire pump with the cap valve missing but...

[DGXSER]

Do you have a compression gage? Like THIS..

Have you tried to get compression with the starter? The age old way to see if its rings or valves is try for compression, note the value. Now add a teaspoon or two of oil to the cylinder, let it sit for a minute or two and then repeat the compression check. If the compression goes up with the oil it is rings, if not it is valves.

As to head interchanging, You should be able to use any head on the engine. If you use an 80 or 81 head on an XJ (YICS) head, then you just no longer need a YICS eliminator. I belive the 80 and 81 heads have the same combustion chamber, and valve sizes as the XJ.

[KA1J]

Just shoot me....

I went out & bought a compression tester (which they said I could return if I wanted).

To the good, amazingly the #2 did have compression.

To the bad....

Cylinder 1 dry 100
Cylinder 1 wet 140

Cylinder 2 dry 80
Cylinder 2 wet 135

Cylinder 3 dry 80
Cylinder 3 wet 140

Cylinder 4 dry 105
Cylinder 4 wet 135

Lovely, just lovely.

Not sure what to do at this point. Guess it needs rings

[tcoop]

If this bike has been sitting and neglected you migh be able to run it for a while and see if the rings free up.