Hey guys as most of you know, i installed a dynojet jet kit and my bike performed perfectly but yesterday after i fixed the jet kit and rode it, i took it for a long spin and today also i was running the bike alot.. At the lower and higher rpm's the bike has a perfectly crisp throttle but when i suddenly accelerate and the bike hits the middle rpm's it kind of has a flat spot, i dont know exactly how to explain but it sounds like a slight bog.. But as soon as it hits the higher rpm it pulls really hard.. What is causing this bog? I'v heard bogging occurs when the bike is rich, but how could it be as when i had the stock jetting i took off the air box lid to check it out and it had the same problem.. So basically at that time my bike was running lean.. But now its running richer (to compensate for more air flow with the open air box).. I read the dynojet trouble shooting paper and it said "as a rule of thumb if your bike has trouble during accelerating hard it means the bike is rich".. I want to make the jet needle clip position higher to make it richer, could it work? Its currently on the 3rd position from top, i was thinking maybe upto 2nd position? I dont think this problem has anything to do with the main jet because when it hits the higher rpm's the bike is out of this world! And by the way, i didnt adjust the mixture screw according to the dynojet manual (2 1/2 turns).. I kept it stock which is about 1 3/4 turns.. Please help!

Jamie

 

Lot's of factors come into play but I would say the two main ones are: Your elevation and which #jet(s) you're using. I went with the clip on the second position from the top after riding it for a week with it on the third - it ran a lot better - up one. Playing with the mixture screw might make a slight difference and is the easiest thing to adjust before pulling the carb so start there. I'm assuming you have a performance muffler with the mods. Also check your spark plug.

Below is a link to KLX250 jetting mods on my website that also may help.

http://www.climbingschool.com/KLX250_Jets.pdf

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no pipe?

 

+1 on the pipe.
You need to get more gas out.

 

Oh yeah.. I have a Great Pipe too.. Its a brand called RSV..Heres a pic of it :



I'm at sea level.. And my jets are:
128 Main
35 Pilot (stock)
DJ Needle with the clip on the 3rd position.. Gonna change it to 2nd position to see what happens..

Should be alright yea?

Jamie

 

You might want to check that the DJ needle is seated in the slide correctly. I've read that it can be a tight fit, and sometimes needs the hole opening up some so the needle will sit fully on the selected clip. Symptoms of this problem are rich running in the midrange, bog, as the needle is sitting higher (richer) than you intend.
Just a thought.
Easy to check.

 

My needle is seated there with no friction at all.. So its lying on the clip i selected.. One minute though, do the symptoms i have mean the bike is rich? And putting the needle into 2nd position will make it a tad richer?

Is this theory correct:
Going up-Getting leaner
Going down-Getting richer?

Thanks alot,
Jamie

 

Needle up, clip down from top= richer.(more gas through the jet)
Clip up towards top, needle down= leaner. (less gas through the jet)
You may need second clip from the top of the needle. Lean it out a tad in the midrange.

 

I got two clips in the dynojet jet kit, i dont know where exactly to put the other one in.. What is the effect of me putting the other clip at the top?

 

The second spring clip is a spare (for when you drop the first one, and can't find it).

Did you get the 2009 klx250s kit? Some are writing the 300 kit is better. I bought the 2009 klx kit.

I spent three hours putting the kit in my bike, and have no desire to tear it down again during riding season. How long is it taking you to get in and out?