Another Pipe Question....

[Beta-cat]

OK, so heres the full story. I have a DG Krome exhaust, K&N Airfilter w/ precharger running on an otherwise stock 300EX. I rejeted tonight and to a 128 main (up from a 122). I let the machine warm up for about 5 minutes then took it for a spin. Well the machine was bogging like crazy past quarter throttle. I jetted back to 125 and it seamed a little better but still a massive bog at half throttle up. I went back to stock 122 and tried the same thing and it was doing exactly the same thing. I changed the plug after each rejet and the plug was black. I adjusted the airscrew the further in I moved the screw the better it seamed to run. I could almost get moving decent but still a massive stutter in the upper half. Please help. I am supposed to be going on a overnight quad ride leaving Friday evening. Last chance before the new baby gets here in a couple of weeks. Thanks in advance. Sorry so long.

[Beta-cat]

Anybody!

I'd say maybe move the needle clip down 1 notch to raise the needle up for more gas flow..

[Beta-cat]

I don't have a manual, where is the needle clip located. Thanks.

[Razorback]

i assume your carb is similar to the 400's. you will have to take your plastic and gas tank off, then get the carb off, then take the throttle cable housing off where it goes into the carb. then, you'll have a couple of screws in the opening of the carb (from the top) that you'll have to get out, then pull the needle out and you'll see the clip.

keep in mind what rico said, move the clip down a notch to move the needle up.

[Beta-cat]

Thanks guys. Does it make sense that it seemed to run better with the air screw in further? If this doesn't work tonight, I am going to go back to stock for this weekend. Thanks again.

I'm not familiar with the 300ex carb,,but the fuel screw/air screw is only gonna effect the lower part of the carb circuit,,once you get past I think 1/4 throttle your dealin with the needle at that point..

[Beta-cat]

Then that would make perfect sense. It seemed that 1st gear was no problem. Once I started reving higher in higher gears, that is where the troubles started. Thanks guys.

[Beta-cat]

Sorry, Wouldn't lowering the clip and causing more gas to flow through the carb cause it to bog more. From looking at the plug, I am running way too rich. Thanks.

Yeah your correct on it boggin if too much gas is getting in,,but of course it's kind of hard to troubleshoot over the internet...go here for some good reading on carbs..

http://www.exriders.com/jetting/jetting.shtml

[Rastus]

Take your plastic and tank off. Take the side of the carb off, and disconnect the throttle line.Make sure not to touch the throttle settings.
Then, there should be a goldish looking platr on top of the carb, take those 3 screws out. The needle clip should be visable. id say,raise the clip some, just try diffrent settings.

Raiseing the clip will let the needlie sit lower, which will make it leaner. Hope this helps.

[Rastus]

So, ultimately, raise the needle clip up. Im not to sure how many grooves to raise it.
Is your main jet set right?If its bogging at 3/4 or full throttle, its to big of a jet.
Id say a 128 would be about the right size.somewhere close around in there.

[Beta-cat]

DG suggested a 125. I installed a 128 and it was really boggy, I dropped to a 125 and it was the same. I then dropped to a 122 and it was exactly the same. The plugs are completely black. I was going to just pull the airbox lid and see what happens to the performance. If it runs right then I know I have to drop at least 2 main sizes. I was told to try with the choke also. If the choke makes it run better then it is lean, worse means rich....

[Rastus]

Is this happening at 1/2 throttle, or full throttle?
If most of the test riding was at /2 throttle, its the needle clip, if its at full throttle is the main jet....

[Zero Z400]

I don't think its ur main jet, i think ur problem is ur needle clip position. U need to raise the clip so you go leaner. Find a mechanic that can help if u r clue less. Check out that link Rico gave you or try this one http://dirtwheelsmag.com/detail.asp?id=138 and see if that helps.


Later

[TRX_Thumper]

That doesnt make sense tho......a muffler an filter and you are running stock jetting and u need to lean it out..cuz its rich.....nawwwww somethin aint right......

[Beta-cat]

That is exactly what I was thinking. I am going to install the stock pipe until after this weekend. I am heading way outside of cellular range and I don't want to take any chances. Thanks for all your help.