K1100LT, not running on all cylinders

[richo2006]

Hello,

1993 K1100LT.

I attended a Horizons Unlimited riders meeting in Appomattox VA last weekend, 4/25 - 4/28. On the way home to Commerce Township (NW of Detroit) I noticed a lack of engine power while going up an incline. Then as I approached a toll booth along the W. VA turnpike the engine stalled. I was able to restart it, but it was running rough, popping, no power. Not running on all cylinders. I have a little over 300 K miles on K bikes and I've always done all my own maintenance. I've never had anything like this happen before.

Anyway, the only I've check so far is to confirm I have spark to all plugs. The next thing I like to do is check compression and then the injectors.

Any help is appreciated.

Richard Flood
Commerce Township, MI

 

[98lee]

Any chance you got some bad fuel along the way? A small shot of water can screw up the filter and cause the bike to run poorly.

 

[richo2006]

I've looked inside the tank several times looking for any water etc. It looks clean. I'll check it again.

 

[pauls1150]

Water settles to the bottom, so you probably can't tell if it's there.
Water will also plug up the filter.

 

[richo2006]

Thanks, I'll replace the filter later this week.

 

[richo2006]

Well, no need to replace the fuel filter. The problem is there is zero psi of compression on cylinder 3. I don't know why yet. The next thing I'll do is remove the valve cover and have a look.

Regards,


Richard in Commerce Twp. MI

 

[98lee]

Burnt exhaust valve or carbon between valve and seat. Check the valve lash on that cylinder.

 

[richo2006]

Will do. We are going to have a K1100 valve lash and cylinder head removal tech session on Saturday May 4, if anyone is interested.


Regards,


Richard in Commerce Township, MI

 

[98lee]

Before removing head, take your compression tester hose, screw it into the bad cylinder, make sure that cylinder is at the top of the compression stroke (all 4 valves on the heels of the cams, not the peaks or shoulders) and put air from your compressor into the cylinder. If a burnt exhaust valve or held open exhaust valve from carbon, you should hear the air rushing out the exhaust. Probably a good idea to have the bike in gear, on the centerstand, with your foot on the rear brake, as the air will try to turn the engine to the bottom of the powerstroke.

If the problem is an intake valve, you should hear it through the intake system and notice a difference when you open and close the throttle. Rare to burn an intake valve. Might be carbon.

If the problem is a holed piston or broken rings, you should hear it through the oil filler hole (you will always get a little through here from normal blowby).

 

[98lee]

You still need to check the filter. Plugged filter = lean mixture = burnt valve. Remove filter, pour out all fuel, let dry out overnight, lightly blow through in direction of arrow. There should be VERY little resistance, like blowing through a large diameter (milkshake) straw.

 

[richo2006]

Thanks again for the info

Regards,

 

[richo2006]

With #3 at TDC I blew air in the spark plug hole and the air came out the muffler. I picked up a '94 K1100 donor with 30 K miles. Before i install the new engine, I'm going to replace the rear main seal and clutch "O" ring and check the valve clearances. I'm going to clean and use the injectors from original bike.

Anything else I should check etc.?

Regards,

Richard in Commerce Twp MI

 

[98lee]

Maybe a compression test before you go to all the work to install it?

Send the injectors to Mr. Injector in Coeur de’Alene Idaho to have them serviced and flow tested. A bad injector may be the cause of a lean running cylinder that burnt your #3 exhaust valve.

 

[richo2006]

Thanks again for the info.

 

[richo2006]

We had a tech session on Saturday Jan 18, to take the engine apart to see why i had no compression on cylinder #3. As I expected it was a bad exhaust valve.

The engine had about 126K miles when this happened. Any ideas what would cause this?

 

[52184]

The engine had about 126K miles when this happened. AnView attachment 100063y ideas what would cause this?

See post# 13 by 98Lee, to which I would add insufficient valve clearance.

Best,
DeVern

 

[omega man]

We had a tech session on Saturday Jan 18, to take the engine apart to see why i had no compression on cylinder #3. As I expected it was a bad exhaust valve.

The engine had about 126K miles when this happened. AnView attachment 100063y ideas what would cause this?

I think the last time I saw something like that, I figured a piece of carbon got stuck in the valve seat area allowing combustion to erode the valve seat. 126K is a lot of miles in which a lot can happen.
OM

 

[richo2006]

Here are a couple of photos of the bad valve. It certainly looks like something was holding the valve open and allowing the exhaust gases to erode the valve seat. The color of the carbon deposits on the cylinder head and valves doesn't seem to indicate it was running lean.

Regards,

Richard in Commerce Township, MI