ProbeGT-ZE

Hey guys, I bought another CBR. This time it's a '95 F3. Not much different than the F2 aside from having a TPS, coolant lines in the carbs and ram air. Bike has 14k on it and I'm having an issue where the bike only runs on 2 cylinders. An even 2 cylinders. As in, it sounds like a 500 but with about half the power since they're fighting the compression from the other cylinders.

My issue starts with the fact that I just took the carbs apart and the jets are extremely clean. Nothing plugging them up at all (well..one slow jet was clogged a bit but I could still see through it). My concern is that I might have a bad coil. Since our bikes run on a waste spark setup if the coil stops working 2 cyl stop working. Since the cylinders are opposite each other the bike actually doesn't run unbalanced (1 - 4 and 2 - 3).

I'm not sure how to go about checking them. I'm about to finish up the carb clean and want to make sure I don't put it back together without fixing the problem. Any input guys?

skr00zloose

swap the coils around and see if it runs on the other 2 cylinders. if it does, you have a bad coil or bad wiring to the coil most likely.

Which cylinders are firing?

ProbeGT-ZE

Not sure yet. I'll test the leads going to the coils to see if they're getting power. If one of them isn't then it's probably the wiring, if it is, then it's the coil...whichever one isn't firing.

ProbeGT-ZE

So I'm just wondering. Is it possible that the carb's might not be delivering fuel to 2 cylinders despite everything in there being honky dory? I also noticed that even though they're so clean the throttle is very sticky and doesn't snap back like it should.

skr00zloose

that's possible.

if you want to check which cylinders are firing, just start the bike, let it get a lil warm, and squirt a lil water on each header pipe. the ones that are firing will dry almost instantly, the ones that aren't won't.

if it's 1 and 4 firing, or 2 and 3, I'd put my money on a coil. if it's 1 and 2, or 3 and 4, it's probably not a coil.