lack of compression on number one cylinder

[ajl]

What are some reasons for low compression in the number one cylinder on a gl1100?

 

[slabghost]

Most likely reason is valves too tight. Second is possibly a bent valve. Possibly a holed piston or broken piston rings.

 

[dan filipi]

By low, what are we talking about here?
I think the book says anything within 20 lbs of each other is ok?

 

[ajl]

cyl one 95-cyl two 155- cyl three 170- cyl four 160

 

[slabghost]

If the bike has been sitting a long time. Set the valves and ride it a few times then recheck compression. Rings sometimes get stuck.

 

[ajl]

Thanks I think I'll try that. It has been siting a while, just don't know how long. I bought it in pieces.

 

[slabghost]

probably sat a long while then. Fresh oil with 1/2 qt of automatic transmission fluid in the oil will help clean things up and help loosen the piston rings. BTW for proper compression read. Warm the engine first. Then with all plugs removed and throttle wide open crank until compression does not go higher.

 

[ajl]

Would ZMax work also or any other product that promises to increase compression?

 

[dan filipi]

I wouldn't bother with any additives like that, running it will most likely bring the compression back.
I've had it happen on 2 engines.

 

[toytender01]

I agree with the others add some ATF and run it for a while then recheck don't make problems for yourself untill you have to :Egyptian:

 

[cmonSTART]

Would ZMax work also or any other product that promises to increase compression?

Snake oil.

 

[dan filipi]

Would ZMax work also or any other product that promises to increase compression?

Snake oil.

Agreed.

If worn cylinders and rings, broken ring(s) etc are causing low compression there's no additive that will put that metal back.

 

[macka]

Would ZMax work also or any other product that promises to increase compression?

Snake oil.

Yup, my snake runs better on it too :smilie_happy: , my old jeep was no better though. In my defense though, I got a bottle for free in a contest.