I have a cbr600f4 with about 34,000 that has a problem with cylinder #2. I've used different coils and different spark plugs from other cylinders, and it continues to have problems with #2. When I remove the coil I get sparks on the sides of the coil but the motor runs the same if I completely remove the coil.

What should my next troubleshooting steps be?

 

Since the plug and coil have been ruled out, next is the #2 carb and valve clearance check.

 

Would a compression test cancel out valve clearance possibility? The carbs are visibly (like new) clean. What will I be looking for when checking carbs. Thanks

 

You can do a compression test if you have the tools to do it. It'd probably be a good thing to check anyway. Still, at 36k, the valves could use a check/adjustment. Don't rule out a valve if the compression tests good. A loose valve wont show up as low compression.

As for the carb, a speck of crap in one of the jets can cause all sorts of running problems. Also, the need to be synced together and jetted properly to work right.

 

I also heard that a warning sign of bad valve adjustments is trouble starting when warm. I had that problem. Is there a write up on valve adjustments?

 

Here's one from here about checking them:

https://cbrforum.com/forum/how-mecha...r600f4-143035/

If you need to adjust them, look through some of the youtube links or dig deep into the how to section and look for a tutorial. Don't just look for F4 stuff as all of the F series bikes, early RRs, and even other makes are very similar.

 

I was able to check my valve clearance. It looks like my cylinder #1 needs some work. Cylinder #2 was giving me problems to begin with and it looks fine. The next thing ill be checking is my #2 carb and compression test.


I attached the measurements I got.
Is it safe to ride easy with a cam out of spec?
Can somebody also tell me which shims I should replace. Thanks

 

#1 exhaust is a little tight. Not too bad though. To determine which shim you need, you need to see what is in there now and go to a thinner shim. Probably the next size down.

#2 intake is a bit tight as well. I would give that one some more clearance too.

It's better to have the on the loose side rather than the tight side. A tight valve can burn and become a serious motor problem.

 

+1

You're about .001 inch out of spec on #1's exhaust. That's not a cause for immediate concern, but tight valves can cause a few issues.

Next is giving the carbs a good cleaning/sync.

And then if it's still an issue, you'll want to check compression.

 

I performed a valve adjustment and also went through a compression check. Everything is reading fine now. It still doesnt run on all four cylinders.
I was told that too much fuel into the carbs can cause these problems. I bought a low pressure fuel pump recently and this happened about 100 miles after. What else should I look for or change?