Compression

[Guest]

I picked up a 1981 GS650G in a barn deal with another bike last fall. It's now time to see if it will run. Got the bike started fairly quick and realized the outer right hand cylinder was not getting hot. Carbs were cleaned, valves clearance/shims checked per manual, spark at all four plugs, compression at around 125 at each cylinder. 1:Is that enough compression to continue my effort to bring the bike back to life or does that compression indicate a top end job? 2: Did I pick up a piece of crud into the number four carb that is preventing proper fuel flow to this cylinder being I have spark?
Any help would be greatly appreciated. Really would like to bring it back and semi/cafe' it out and ride her. Thanks, Mike

[Nessism]

Please check the Newbie Mistakes thread linked in my signature to see if anything applies. Check the carb rebuild tutorial while you are at it to be sure you didn't forget anything too.

Good luck.

[tkent02]

125 is great for a bike that's been sitting a while, the fact that all four are similar is great.

Your carburetors need attention, they always do.

[Mike Stenseth]

125 is great for a bike that's been sitting a while, the fact that all four are similar is great.

Your carburetors need attention, they always do.

Thanks! That's the direction I was looking for from a forum member. Have been reading and re-reading all Suzuki Newbie material and articles pertaining to my issue and have found all very helpful. I actually love working on motorcycle carbs so cleaning and cleaning again is not a problem. I'll post and let you know what I run into with the carbs. Mike

[Datsa Noydb]

Did you sync the carbs? One cylinder 'cold' could be that that carb is not open enough.

[tkent02]

Could be synch, although if you open the throttle a bit the cold one should start firing. Is there fuel in that float bowl? are all of the tiny passages in that carburetor open? choke feed tubes? how about the little tiny ports near where the throttle plate closes? The passages around the mixture screws?
If you shoot some spray carb cleaner through these places the pattern that sprays out should be identical an all four carburetors.

Could possibly be a spark plug that won't fire under compression but that works fine when you test it.