neddle position Question

[biggstr6]

Needle Question
I picked up a 04 200 the other week for $1100.00, looks kinda rough was ridden /raced & shows it, but I think I got a good deal .

I'm sorting things out. It has a bit of a bog off idle like its loading up then clears up & then hits.

It has a 180 main ,42 pilot,#5 slide and needle clip in the middle position (dont know what kind of needle.

I cleaned all the jets out, and was playing with the needle position . with the clip in the second position from top ,and air screw 1 3/4 turns out runs much better , but with the needle in the top position it runs even better.


My question is is it OK to leave the clip in the top position ? I dont want to damage anything by running too lean .

Or should I maybe try a 40 pilot, or something else. #7 slide, or a cck needle ?

This carb stuff is all new to me so I would be grateful for any help.
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[moto9]

The plug color on a 2 stroke will tell how the fuel to air ratio is.
Check it...tan is good, black is rich and white or metal color is lean.
So, as long as you in the tan-ish color range keep going leaner, until your satisfied with how the bike is running along with what the plug color looks like.
I run a cck with a 40-pj and a 175-mj on a 08 300, and it's about spot on.

Just for info each circuit overlaps each other, from idle to wide open...and the air screw is basically an adjustment for the pilot jet.
Ideally the pilot jet at a true #40in size the air screw should be at 1-1/2 out...so that when you ride at a different elevations and/or different humidity/temps you can adjust the the air screw in or out giving the pilot jet an adjustment range from 35-45 depending on adjusting it in or out....make sense???
I'd leave the 40-pj I think a 38 is too lean...play with the clip positions, air screw and maby drop the main jet 1 size, before spending cash on another needle or slide.

 

[biggstr6]

can you go by the plug color even with out a throttle chop?

Right now it has a 42 pilot & 180 main ,thats why I was wondering about a 40 & maybe a 178 or 175.

 

[moto9]

can you go by the plug color even with out a throttle chop?

Right now it has a 42 pilot & 180 main ,thats why I was wondering about a 40 & maybe a 178 or 175.

I don't think you'll get an accurate reading off the plug, but it may tell you something if it's way off, black and suitty, too rich or pinging if it's lean.

On low speed throttle positions I go by feel...I start on the rich side and lean it out until I feel that I'm in the zone with the PJ.
you'll know your going in the right direction if you feel the throttle become crisper and cleaner...too far and it'll start to ping
Once your close with with the PJ you can fine tune it with the air screw.

Working on the mid to 3/4 throttle positions, start with the needle clip positions...since you think it's too rich work the clip up with test rides between adjustments.
If you top out on the clip and still think it's on the rich side, try a leaner jet...clip in the middle and work the clip upward again.
So you can see a method thru testing.
I like to do plug chops because I want to know right away if the jetting is too rich or too lean before I start the above process.
I can usually figure out what changes to make by plug color and then compare that against how the power feels and current carb settings.
Once you've been in and out of your carb 1/2 dozen times you'll be able too as well.

Just as a note, I run my jetting a little on the rich side for better slow speed cooling...most of the riding I do is tech single track
Hope that helped some.

 

[biggstr6]

Thanks , Yes that helps.

 

[webmaster]

Just an fyi - if you go with a leaner slide and leaner needle - you typically richen the pilot. Be sure to reset your idle as you change your jetting. The fuel provided by the high idle will make it so that the carb is "pulling over" - the circuits are no longer well separated (which is something that this carb has an issue with).

To really clean it up - think about sending the carb to RB-Designs to be re-worked - he does quite a bit - including modifyng the carb internally to make the idle/off-idle circuits more sensitive and cleans them up.

jeff

 

[biggstr6]

Any Idea what RB would charge ?

 

[dank]

go to his website, he has a description of what all his carb mod entails.

 

[webmaster]

www.rb-designs.com

The first two things I would do is head mod to dial in squish band and increase motor efficiency (also cleans up low/mid rpm running) and carb mods.

jeff
webmaster
GasGas Riders Club