Low Compression, can penetrating oil help?

[Anonymous]

Found I have one cylinder on the 82 GS1100 running at below 100 psi and the others are 130-135. Mileage is 24K.
I figure I will need to at least have the cylinders honed and install rings.
But before I teardown the top end, thought I might try putting penetrating oil in the cylinder to see if might break loose a frozen ring (if that's the problem).
Is it possible that the penetrating oil will "eat" something I don't want it to?
Like the combustion chamber or the top of the piston. Don't know if it will damage to aluminum.
I've heard of this being done in car engines (all iron, like older small block Chevys) but not a bike engine.
Any thoughts?

 

[Billy Ricks]

Penetrating oil shouldn't hurt anything but you should change the oil after trying it. It will make its way past the rings and into the crankcase. I've never had your problem but if you indeed have sticking rings I'd be inclined to use gun solvent. It's pretty similar to carbon-tetrachloride which is a banned substance. It will dissolve carbon and gummed up varnish and oil deposits better than the penetrating oil. After it has been in the cylinder a few minutes crank the motor by hand using the right side of the crank where the signal generator is located. Do this several times adding a little more solvent each time. The last time leave the solvent in the cylinder overnight. Again, you should change you oil after doing this and before you start the bike again.

 

[focus frenzy]

Older small block chevy's had aluminum pistons.
I am not aware of any penitrating oils "eating" aluminum, it may help if the engine has been sitting for along time, but I doubt it will do any thing if the engine has been in regular use.
It wont hurt to try, but you will need to change the oil after you put it in it because it will contaminate the oil.

If you decide to replace the rings, make sure you have the cylenders checked for deminsions all the way around the bore and through the complete stroke.
when I bought my 1000g the previouse owner had honed the cylenders and installed new stock size pistons and rings, but failed to discovere that the cylenders were worn to nearly 1mm out of specs.
when I got it, the compresion was just in specs but it drank oil like a two stroke.

 

[Anonymous]

The exact same topic cropped up on the third page of the Fuel Economy post. There I recommended a product called Berryman's B-100 Chemtool, which does a great job dissolving carbon that may be keeping the rings from doing their job. Check the complete thread...

Roger