So it's time once again to turn to the mighty beeb for some help. I'm working on the wife's 250 ninja and am having issues with the throttle and I'm not really sure where to start with diagnosing the issue, so let's see if I can exlpain this well enough to make any sort of sense. I'll let the bike warm up enough to a point that it will idle without the choke on, (so the rpm's are around 1200 or so) at that point, once I twist the throttle the revs drastically drop and it usually kills the motor. If I can get the rpm's higher (closer to the 3k-4k range) then I can rev the motor up fine enough. It's almost like there's a delay or something once I twist the throttle. I'm not the most experience with carbs, and I'm curious if the issue is in that area? like maybe the jets need to be cleaned or something? What does the wera board have to say? (and thanks in advance for the help. )
Until the engine is warmed up that's normal. If it still does it, pull the carbs, take the float bowls off, and clean the pilot (starter) jets. Ethanol... If the float bowl is green inside, dip the whole assembly in yamalube carb cleaner overnight....
Lean pilot circuit. These bikes are set super lean from the factory for emissions reasons. I had a similar issue before I had the bike tuned and solved it by putting a 6/32" washer under the needle as a shim. Solved the lean bog for a temp fix but I had the bike Dyno tuned and they made major jetting changes. Now the bike runs and pulls everywhere in the power band.
This man types the truth... Shimming the needles is a very easy and common fix to this all-to-common problem. For everything Ninja 250, refer to the forum Ninjette.org there is a ton of knowledge there too.
This is why I like the Beeb. always full of help, and depending on the question a lot of sarcastic replies. (thankfully not in this case though) Thanks for the help.
