My KLXhas a KLX300 stock exhaust on it, UNI air filter, no airbox lid and running a 128 main jet (up from the 118 stock) in the CVK34 carb. Previously I had been running a 125 main and the airbox lid with the snorkel removed. It ran ok and pulled steadily to redline at 10,500rpm. Pulling the airbox lid and it would surge above 7000 rpm with the 125. I've gone to the 128 and it pulls great down low all the way up to around 7500 rpm. Above 7500 the motor pitch doesn't fluctuate like it did with the 125, but there is still a feeling of the bike pulling ahead and dieing out and pulling ahead again. Also in the lower gears where it spools up very quickly if I take to 9,000 or higher before shifting it seems like there is a dead spot when I get back on the throttle.

Should I bump it to a 130 main or does this sound like the float level is off? I was wondering if it was the float because of the response when I shift. It's almost like the carb is empty and it takes a second for the gas to fill it back up because there isn't any vacuum pulling fuel in when I close the throttle between shifts.

For what its worth I'm at 200 feet above sea level and with the airbox lid on and the 125 main it was running slightly rich. After changing to the 128 I did a 1/8th mile full throttle run in 6th gear, hit the kill switch and coasted in. When I removed the plug it was a light tan, just lighter than say chocolate milk.

 

You gotta make your next post count, you soon to be "*****":-) You can be the mad tire scientist of PWI.
LOL

 

Sounds like its still a little lean

 

yea sounds lean, mine was doing that..... i did what you said, put the airbox lid on with out the snorkel.... i think thats the ticket there... no dead spots or surging, i think im leavin it there.... 128 main, stock pilot, 2.5 turns, no snorkel, but the lid is on.... uni... but i have the full BG

 

Yeah, it sounds like a lean surge. I would try bumpingthe main to132 if you want to leave the lid off.

 

I think I'll try the 130 next as the 132 seems a bit much for what mods I have. I don't want to overdo it only to have to pull it back apart, the carb is irritating to remove. Although I will be going with the 331 eventually, should I order the next 2 larger jets for that just in case?

 

I'm running a FSW header with the FMF powercore IV and i have no airbox lid along with a 128 main and i just switched back to the stock pilot due to it running rich....I'm at about 350ft elevation just NW of philly. PA. My bike no matter what i do seems labored to run to the redline ....
My plug reads a perfect color though so i'm also not sure what to do.....LOL....the #40 was way to heavy on the pilot circuit but i also have no missing,sputtering or surging.I think it's gearing.......If i switch to my 14-49 combo she screams out but if i go to the 14-45 it is labored.......Then i realized it's still only a 250 and it's not a rocket ship......
Personally i'd do a plug reading to nail it....just like you did but you should no way have to fiddle with your float level.maybe raise your needle clip position some but that's it.Maybe go to a 130 main and a #4 position on the clip.....I'd try that and see what happens.
My bike also runs perfect with my settings and will scream out just fine with the lower gearing and the plug reads good.....you should set your gearing where it will stay for your test and go from there.

 

I too found the 40 pilot to be to rich. The stock seemed to lean. I went with a #38 pilot no air box lid clip in 3rd slot and a 132 main with the full Muzzy and high flow filter. I did finally get to the point where I said f**k it and stopped trying to fine tune it and just rode the bike. It seemes to run good at these settings though. I am also in NE PA, elevation close to you.

 

When I had 13/42, 125 main, and no lid it would surge at 60mph in 6th at roughly 7000 rpm 3/4 throttle. With the 128 14/42, 128 main, no lid I get a similar feeling in the lower gears about 7500 rpm but not as severe. To duplicate the first results I can just leave it in 5th and it pulls the same rpm/throttle setting as 13/42 +or- a few hundred. I put in the 130 last night and cleaned my UNI filter. I would love to find a faster way to dry the foam filters aside from wring the water out and let dry overnight but oh well. I'll take a ride later on today and report back.

 

Patrick said he has like 6-8 filters, no toil? maybe cant remember which brand he said it was, he said they were only like 9$ and he changed his filter after every ride and cleaned another one and let dry, so im assuming he had one at each stage of cleaning almost all the time.... but he rode alot and some crappy dusty stuff.... i have the uni too....