I'm a new member and this is my first post. I have a 95' CBR 900 and the bike was running fairly well after sitting for a few months. I changed out all the gas and gave it an oil change, and now the bike runs like crap. It starts right up with the choke all the way up, but will stall as soon as it is dropped, even after warming up for several minutes. The engine can be forced to start without the choke when its warm by cracking open the throttle and keeping the revs above 3,000. I am positive that this is a goddamn carb problem as the engine run will run with the choke on (getting more gas than it would without) but stalls without choke or excessive throttle. I have not ridden the bike and am unfamiliar with CBR's in general as I have owned Yamaha's and Suzuki's primarily. If this problem sounds familiar to anyone let me know what you think I should do. I'll do a good carb cleaning as soon as my shop manual arrives. THANKS

 

Sounds like the idle jets are clogged. With the manual, cleaning carbs is a fun learning experience.

 

http://www.stephygee.com/900RRmanual.zip

44.4 MB zip file

 

get it started and go for a long run, and don`t go easy on the throttle, blast the ****** out!

 

Hey all. Just wanted to let everyone know I got the problem solved. Turns out the fuel pump was getting intermitten power from the relay, leading to a lean condion. This expains why the bike would only run the choke all the way out, the engine was only barely sucking in enough feul through the pump. I'm slightly concerned about this because in the time I took to diagnose the problem I ran the bike for around 15 minutes at varying RPM's (mostly at idle) on what seems now to be a very lean condition. And on the last running of the bike, it did not sound that bad at idle. So I'm a little pissed but I will have the new relay by Wed and then I can put the fears to rest. Keeping the fingers crossed until then!

By The Way: this is an excellent example of why not to ride or try to "rev out" an engine problem...when the engine is running like ****, turn it off and do some thinking.

-Thanks for the inputs though, it could have been a number of things.