So I have a 2004 Ninja 250,It has a K&N filter and the dynojet kit using the .98 main jet.Up until recently this bike had a full Muzzy exhaust,but I have put back stock exhaust,and actually it runs much better and I enjoy it more.Anyway I notice a slight surge when going a constant cruising speed maybe between 5000 and 7000 RPM's.It idles perfectly runs smooth to redline when you get on it,warms up easy.So my question is do you think it is a little rich or a little lean? I have recently cleaned the carbs.Logically it should be a bit rich because i switched the exhaust,without changing anything else,but doesn't have other symtoms of being rich.

Normally surging is from a lean condition, check the needles and maybe try one clip lower to move the needles out to see if that helps.

Normally surging is from a lean condition, check the needles and maybe try one clip lower to move the needles out to see if that helps.

Ok I'll give that a try,going to try it without pulling out the carbs this time.So your saying to go from say 4 notches to five right?

It's worth a try, if it gets worse then you know which way to go next time. If it get worse on 3 than there is something more complex going wrong and it's time to pull the carbs and see what is happening.

Also check spark plugs and wires, I've had odd things happen with a loose plug letting compression change, also note that some plugs will start to leak around the ceramic which can cause odd things too.

It's worth a try, if it gets worse then you know which way to go next time. If it get worse on 3 than there is something more complex going wrong and it's time to pull the carbs and see what is happening.

Also check spark plugs and wires, I've had odd things happen with a loose plug letting compression change, also note that some plugs will start to leak around the ceramic which can cause odd things too.

Yeah thats a thought,It's got new plugs,maybe I didn't get one tight.Thanks for your suggestions.

usually surging at a constant cruising speed indicates a lean spot in the idle circuit. I fixed mine by adjusting the mixture screws. you can try going one notch richer on the needle first, as suggested, but I think that if the midrange is fine now, going one more notch will make the midrange go flat from being too rich.

if it already has a jet kit, perhaps the mixture screw plugs have been removed? if so, it's easy to tune the mixture screws w/o having to remove the carbs.

usually surging at a constant cruising speed indicates a lean spot in the idle circuit. I fixed mine by adjusting the mixture screws. you can try going one notch richer on the needle first, as suggested, but I think that if the midrange is fine now, going one more notch will make the midrange go flat from being too rich.

if it already has a jet kit, perhaps the mixture screw plugs have been removed? if so, it's easy to tune the mixture screws w/o having to remove the carbs.

yeah the plugs have been removed,I believe I have them set at 2 1/2 turns out on both carbs.If you blip the throttle it has no hesitation and returns straight to idle speed,thats why it is puzzling to me.

try backing out the mixture screws till you get a rich indication, then go back in until it goes back to normal.

make sure the bike is fully warmed up when setting the the mixture screws. ride it like 10-15 minutes before to insure it's fully warmed.

also, have you synced the carbs?

I synced the carbs when I cleaned them,but that was before the exhaust swap.I'll try what you said with the mixture screws.

cool... let me know how it turns out. it sounds like you have a handle on how to work on the bike and that's good as fine tuning your jetting takes a lot of trial and error, plus a big heaping of patience. :p

plus a big heaping of patience. :p

Can you buy that at Sam's or do you have to go to the motorcycle shop?:rolleyes:

you can get it at either... it's located right next to the elbow grease. :lol:

well I've been divorced twice,and am a single parent of a 15 year old girl,that I have raised alone since she was 3...so one thing I do have learned is patience.Thanks for your help.

Gordon let me know if you ever take a ride to the north.

This may be out of left field, but if it's really windy where you're at....it could just be the wind. No, really.

Just a thought, before you go tearing into the carbs....

Here's a thread from another site:

http://forums.ninja250.org/viewtopic.php?p=752121#752121

That's a good thread Jerry,thanks.I'm going to keep all that in mind and ride it around some more and try to determine if it is something else.I need to make better notes when it happens like what rpm,wind even type of pavement,thanks again.