300EX jetting at 4,720 ft. PLEASE HELP!!!!

[dasanii19]

I have a 300ex at 4,720 ft. elivation, I just took my carb off and it has a 38 pilot and a 135 main. My mods are full rcm DG exhaust and a moose foam filter with my lid off.

Please give me an idea of where im suppost to be jetted at, also is there a air fuel mixture screw I need to fool with to tune it after I get my jetting right? And where is the idle screw at?

I just got this 1993 300ex because my 04 z400 just got ripped off, so now im trying to learn a little about hondas. anyone that knows any of these questions please reply. I need to get this thing running...

And what MM is the stock carb on the 300ex? And would it be a good idea to upgrade to something like a 39MM fcr off a yfz or 400ex?

And how do I get the damn spark plug out, ive tried all my spark plug sockets and none will fit and let me get a turn on it????

Try to answer all these questions as best as possible. It will be very helpful for me..

[bwamos]

Originally posted by dasanii19
[B]I have a 300ex at 4,720 ft. elivation, I just took my carb off and it has a 38 pilot and a 135 main. My mods are full rcm DG exhaust and a moose foam filter with my lid off.

Please give me an idea of where im suppost to be jetted at, also is there a air fuel mixture screw I need to fool with to tune it after I get my jetting right? And where is the idle screw at?

Idle screw is underneath the carb.. should be mounted to a small bracket on the right/front side of the carb..

135 sounds a little rich for 4700ft. Try to toss a 130 in there and see how it runs.


and what MM is the stock carb on the 300ex? And would it be a good idea to upgrade to something like a 39MM fcr off a yfz or 400ex?

The 400ex carb with a 350x air boot is a great cheap upgrade.


And how do I get the damn spark plug out, ive tried all my spark plug sockets and none will fit and let me get a turn on it????

I use the sheetmetal version that came with the quad. The regular sockets just dont have the clearance. You can get one from the local dealership.

[dasanii19]

cool thanks, do you know what stock jetting is in the 300ex?

[bwamos]

I beleive in most places it's a 122-125. Depends on location though.

[bwamos]

Just to confirm and correct my stock Jetting answer.
Stock Main Jets are #120 or #122 depending on elevation. Slow Jet is a #38.