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View Full Version : 300ex jetting, bogs



Ritthjp
03-10-2007, 07:52 PM
My wife has a 1997 300ex. I've cleaned the carb, made sure nothing was clogged.

It has a Cobra exhaust on it & K&N Filter.

jetting right now is:

Main Jet: 132
Pilot: 38
Needle: 4th notch down
Air/Fuel screw: 2 1/4 turns out

It idles great, and at a slow rev up the RPMS is fine. On decel it backfires a tad. When I punch the throttle it completely bogs out and dies. If I pump the throttle I can keep it from dying.

The float isn't stuck.

Any suggestions?

bwamos
03-19-2007, 02:20 PM
1) for the pop on decel.. I'd bump the pilot up to a 40-42. Especially if you're running no-lid.

2) Top end bog. If it's dying on a quick stab.. make sure the compression arm on the accelerator pump didn't slip off the needle. It happens. It will be under the plastic cover on the side.

If that's not the problem.. bump up to a 135. But you shouldn't have to go higher than that. And even at a 132 you shouldn't be dying. Seems suspect. Perhaps an air leak at the slide cap. Make sure that o-ring is nice and clean.

If it's not actually dying, but just bouncing hard at about 4-5k rpms.. then you're rev/neutral switch contacts are dirty. (Behind your rear brake pedal under the sheetmetal guard.)