jetting

[Tazmanian]

I have a 2004 kdx 220 what do I need to do with the carb when I put on a platinum 2 pipe?

 

[john_bilbrey]

I would get the bike jetted properly first, then adjust as you need once the pipe is on. For reference, I'm running the stock needle (clip in 2nd position), a 45 pilot and 148 main with no airbox lid, Gnarly Desert, and PCII silencer. I could probably go with a 42 pilot, but was suffering a low-end bog, now it's almost a little rich on the bottom....

 

[colhom]

By second position do you mean second from top or bottom?-
Colin

 

[Tazmanian]

Second from top.

 

[Zerotact]

I ran a 145/42 for 2 years on a PC pipe, never had to change the plug. a little spooge, but never fouled a plug.

 

[colhom]

I have the Eric Gorr lowend head and cylinder work too, along with the PC pipe. Where would this put me jetting wise?
Colin

 

[john_bilbrey]

Afraid I can't help you out there. Maybe call Eric, or CC or someone on here with similar work can steer you in the right direction.

 

[Rhodester]

john_bilbrey, try putting the air box lid back on and then going to a 42 pilot and see what happens. You might be in for a surprise. You may even go one lower on the main and see what happens there too.

 

[john_bilbrey]

What is putting the airbox lid back on going to do? Richen it up a little (less air)? I think my problem was with the airscrew setting, I have since adjusted it (temp changes) and it's pretty close to "right", by me. If I get some time (ha ha!) I'll tinker around with it some more (provided I can find the stupid airbox lid!)

 

[Rhodester]

After a year and a half of systematic jetting changes with logging the results I still couldn't get rid of the off idle hesitation without going overly rich on several of the carburation circuits. That sounded a little like what you were describing. I put the air box lid back on (w/o the snorkel) and for the first time was able to run crisp and powerful jetting without the lean hesitation when I snapped the throttle to WOT when running just off idle under a load. Maybe I'm all wet, but whenever I hear of an off idle hesitation that's the first thing I think of. It was quite a revelation to me and a very unexpected fix. You wouldn't believe everything I tried to get rid of the hesitation: 2 pipes, 2 silencers, 3 reed sets, Eric Gorr cylinder base and head milling, torque ring, gas changes, leak down tests, timing changes, air filter and oil changes, Kips cleaning, 10 main jets, 13 needles in various clip positions, 3 slides (throttle valves), 5 pilot jets, and various air screw adjusting.....and finally.... the fix....you guessed it....THE AIR BOX LID!!! I know it sounds ridiculous, but it worked for me....for real!

 

[john_bilbrey]

Thanks Rhodester. I'll give that a whirl when it warms up a little here, provided I can find the dang lid.