I have a 95 GSr and I have a misfire in cylinder 1. I have try new distributor , spark plugs, spark plug wires , new injectors, valve adjustment, compression test, check timing and still have a misfire. Anyone know what can be wrong. Can the lower compression on that cylinder cause that?
Compression test was low on #1 130psi where the rest where between #160-200psi. The spark plug is Blk in cyl.1 compare to the others that are normal. Anyone know what can be the problem or what I can try? Thanks

 

Standard compression for the B18c1 is 270 psi minumum is 140psi, mor importantly is the maxamum variation is 28psi, your at least at 30psi diff. and most likely your problem.

If you do a wet test you will most likely find it is bad rings. 94

 

OP said the that cyl was running rich too I'm thinking "washed walls" either way not a simple fix, Honing will be required either way.

 

Not exactly, what he said was, "The spark plug is Blk in cyl.1" and although that may mean cylinder 1 is running rich, kind of depends on if it is dry black or wet black and ops definition of "black".

Just saying.94

 

It was a dry Blk. I did a cold compression test #1 145 #2 155 #3 165 #4 190
I added a little oil to #1 and got 200psi

 

The low compression is a problem, fix it and it may solve your misfire problem, it needs to be done anyway, sooner then later, it will only get worse not better.

But do the leak down test to see where compression is going, a wet test will only confirm if it is the rings, unlikely to be a washed cylinder wall as engine does run and that would "re-lube" the wall. 94

 

I realize the misfire is more on idle or under 2k rpm. I don't notice much misfire while driving above 2k rpm.

 

If the spark plug is black, that means that you are getting fuel built up in the bottom and its igniting inside of the motor. Cylinder 1 might be burnt up because of that. You might have to take the head and block apart and have them cleaned.....good luck.

 

What is needed to be clean? In that cylinder?

 

^no it's called carbon build up and you can clean it off with brake parts cleaner. but it won't really help just wipe the plugs off. 2nd inspect the cap and rotor just in the chance they're worn down. But 145 is virtually at the "service limit".