I just bought a 1988 cbr 600f. It has a kerker slip-on and a high flow K&N filter. The bike has trouble starting and i believe is running lean. The guy i bought it from said it has stage one jetting and said that i should go to stage two. What size main do you guys reccomend me put in the bike. Also i bought a brand new battery and it fails to charge itself while im riding the bike. Any help diagnosing these problems would help. thanks! josh

 

Do you have access to a multimeter or voltmeter? Seems like a lot of people( including myself ) have had this problem with battery not charging. The most likely culprit is the voltage regulator / rectifier unit. Other problems could be stator, or bad connectors.There really isn't much more to go wrong in that system.
Regulator / rectifiers are a known problem on this bike. I read every thread on this forum relating to it.
Lots of good info. I replaced my reg / rectifier after checking stator output and continuity to ground. Bike runs great now,lights are brighter too. I bought my reg./ rectifier from these people. Only had to change one connector with the OEM one off the part I was replacing.
http://www.bikebandit.com/product/A3390319
Good luck.

 

Can you start the bike if you use the choke? The choke will richen the mixture for cold starting.

As far as jets: Changing your main jet won't do anything for you at startup. It won't really do anything for you except in the higher RPM ranges. Take the carb apart and see if the jet needles have been changed, and what size main jet is on there. There's always a number on the jet somewhere saying what size it is.

Stock main jets are 105s. Dynojet stage 2 comes with 114-116s and 120s. If you are at sea level or a low altitude, if you have a pipe and a K&N you should try at least the 114. Some people suggest that you go DOWN a jet size (.02 or .03) for every 1000 feet of altitude. My bike has a stage 2 kit, a pipe, K&N, and a drilled airbox, and I use the stock 105s because I'm at 6000 feet. If I was at sea level I would definitely need 116s or 120s.

If you're having startup problems I'd suggest you tear your carb apart and clean the $hit out of it, especially the idle jet (35). Them's some little teeeny teeeny holes.

 

i think most of the problemis not having good charge with my battery. If i hook jumper cables to a car and start it that way, it fires up instantly. The bike runs great when it is started. I DID notice that my headlight is VERY dim and doesnt throw much light at all. Does this all sound like the symptoms of the voltage regulator/ rectifier? Also where do i adjust the idle on the bike, it doesnt idle high enough and sometimes dies. About what RPM's should the bike idle? thanks guys!

 

If the battery is weak, even if it cranks over it will be harder to start, because you're getting less spark energy too.

Like billistic said, get a voltmeter. Measure the battery voltage before you start. Should be 12.4-13.5 volts. Start the bike and let idle or run a little higher, 3-5000rpms. Check the voltage. It should be more, like up to 16 or so MAX. If it's not more, or even less than with the bike off, then you have a charging problem.

An 88 should idle around 1200 or so.

 

hmmm,let's think about this...

the reason your battery is not charging is that it's not getting any DC electricity. A little digital multimeter will cost you $10 at an auto parts store. If your going to do your own wrenching you really should have one anyway. Yes, it DOES sound like symptoms of voltage reg./ rectifier but you have to pull apart your bike and take a look at one or two things to be sure. It's not difficult...