Just installed my HMF pipe and rejetted with a dynojet kit, now a cruising speed I get a stutter. Nail the throttle and it pulls just fine. Idles fine as well. I hate the stutter and it bogs down when it does it too. I adjusted the airscrews 3 turns out just like DJ said.

I'm at 200ft, any ideas?

 

Sounds like your needles are off to me. Did you make sure and put the needles on the right clip with the washers in the propper spot on BOTH carbs? If I were you I think I'd pull the neddles and make sure both are set the same and like DJ suggests. An easy way to give you an idea if your rich or lean is to cruise at the speed it pops and stutters. When you get to a level speed and throttle position slowly put on the choke. If it gets worse then your to rich, if it gets better then your to lean. Since the idle is fine and it pulls good at full throttle your pilot and mains are probably good. However if you make big adjustments with your needles then it will also affect your mains. Make sure and check the diaphram it can easily get pinched while working with your needles. I hope some of this helps.

 

Needles are clipped on the 5th groove and have 2 washers shimming them just like they suggest for applications below 5000 ft. I did try the choke thing once and it got worse, I must be running hella rich. I made sure the diaphrams were not damaged/dirty/pinched when I installed the new needles. I followed DJ's instructions for 0-3000 ft.

I did try adjusting my airscrews to 2 1/2 turns down from 3 which I originally had it set at. I'll try 2 turns in, or should I just change the position of the shims on the needles to the 4th ring instead of the 5th and leave the 2 shims?

Here are the instructions I received:

http://www.dynojet.com/pdf/Q219.pdf

 

Try leaning out the needles 1 clip each. Leave the shims like the were. Move 1 thing at a time so you know where your at and what you've done.

 

THANKS! I'll give it a try and post my results.

 

No problem. If it gets worse then go the other way. Mainly remember 1 thing at a time so you KNOW where your at.

 

Emailed Dynojet and this is the response I got:

Make sure that the needle is on groove #5 from the top. Make sure that the 2 washers are on top of the eclip. Check the needle retainer to make sure that it is seated all the way at the bottom of the slide or the needle will bounce up and down causing this problem. Check the flout bowl vent tube where is goes in the bottom of the airbox, it can be difficult to get lined up. With the K&N air filter you should use the DJ140 and DJ144.

Michael Cory
Research & Development
Phone: 800-992-4993
Michael@Dynojet.com

 

My 03 650 does the same thing.come to find out my cam chain sliders were broke for the 2nd time so i jumped timing.Im replaceing my gears and chains& sliders for about $300. i have 6000 miles on my bike so this is most likly not your prob,but i thought i would share info.