I am having an issue with my 95 Cbr 600. I bought it last summer and it seemed to run fine. The only problem was that it needed to warm up for a while to run well. When I would start it, it would Idle at 1300 rpm, but after 3 or 4 minuts of warming up it would idle at 4000 rpm and I would have to mess with the idle screw to get back down to 1300. Once its warmed up it ran great. But at the end of last summer I started having problems getting it to start. It would take a lot cranking to get it to go. I would have to turn the choke on, and hold the throttle all the way open, for it to start, finnaly after 2 or 3 minuts of cranking" it would start, but I had to keep the throttle all the way open and it would just idle, if i closed the throttle at all, it would die. after a good 2 minuts of holding it open it would start to rev up nice and run fine. If i turned it off And came back within two hours to start it up it would start up instantly, but after leaving it over night, I would have to go through the same process of "warming it up" Yesterday, after a long winter of sitting, I couldn't get it started with the starter, and didn't want to fry it so I went down a hill and bump started it with the same results. had to "warm it up" with throttle open for a couple minuts before it would run, once it warmed up, it ran great. What is going on? If you know anything about this problem, any suggestions would be greatly appreciated. Thank you in advance!

 

it sounds like your going to need to clean your carbs. Its acting like the choke is staying on. Basically, when a choke operates like it should, you apply it, start the bike and it idles a little faster than normal, then it will idle around 3-4 grand once its wamed up and you turn the choke off allowing the bike to return to normal idle. Your bike was doing this awhile ago and now wont start. the fact you had to hold the throttle open later on suggest the same thing. Your engine wasnt getting enough air as the choke is stuck and dumping too much gas into the engine. holding the throttle open allows more air into the engine.

Also, your idle is probably set so low to compensate for the stuck choke that the engine cant possible start without the throttle being held open.

Does it smell like gas when try to start it? If it does, then thats more than likely your issue. Does it puff alot of black smoke from the exhaust when you rev it up? again, another sign of running way too rich from a stuck choke.

If you did not store the bike properly, the carbs will get gunked up very easily. gas breaks down in as little as a month, so you can imagine what untreated gas looks like after 4-5 months of sitting.

I would clean the carbs and go from there.

 

I was thinking it might be the carbs or the choke before, but I don't understand why it would run and start perfectly once the bike was warmed up. As for the choke, when it is running, if I turn it on, the motor bogs down like a normal warm motor normally does, and when I turn the choke off, it runs normal again. So that tells me that the choke is engaging and disengaging like it should. I think anyway. Yesterday I was looking at the spark plug caps and a few of the wires looked pretty cracked up. I would just replace all of them, but they are 50 bucks a peice and I want to be sure that it is the problem. Can anyone explain how that might cause my problem? Thanx for you suggestions!