Having issues with the CBR250RR. When cold after I push the choke back in and give the throttle a twist the revs bog down and if I keep the throttle in that position the bike stalls. After it is warm it seems ok. Bike is running a little on the lean side, plug colour is a light browny/grey. I cannot remember what the pilot screw was adjusted to, will check when I get back home from being away. I bought the carbys from @kiffsta and it has larger jets in it but I cannot remember what size. Carbys have been syncronised. Any thoughts in what maybe causing my problem?
Sounds normal. It is not supposed to run well when it is cold. Why do you think it is lean? Light brown/grey is a good colour for the plugs and is most certainly not lean. Here is a good guide http://honda-tech.com/forced-induction-16/***-basics-reading-spark-plug***-3063102/ Please do not consult those guides that you see in Clymer manuals and the like. It is a load of old rubbish for Austin A40s cheers Blair
How long you letting the bike warm up for? these bikes actually have a running temp.. which means if they are colder then that temp they run an asthmatic smoker during a 400m sprint..
Hi Tim, I did not know about the running temp. I don't suppose you could tell me if you know what the running temp actually is?
You want to let it idle for a while to warm up, most bikes are temperamental when cold and will behave similarly. The choke restricts air flow to make the fuel/air mix richer. Pulling the throttle is doing the same thing but by adding more fuel rather than less air. It's a bit hard to predict what is happening if you're fiddling while cold - the bike should be warm otherwise it could be quite a bit of guesswork. Once it is warm, does it hesitate when you pull the throttle? Or does the engine delay its response after you pull it? As funny as this sounds the first thing I'd do is replace the spark plugs if they're not very new. Cheap and you'll have new sparks at the end of it anyway, carbies are very sensitive so if you can avoid messing with them you're better off. See how you go...
I let mine idle while I put my gloves, jacket and helmet on. It is still cold when I get on the bike (talking first ride of the day here) bit is usually ok after about 1km or so.
its not purelly just idle.. i leave the choke on until the revs raise... then i take the choke off and ride it...
