I have a 98 Suzuki 500 4x4. I installed a Supertrapp IDS 2 exhaust and am having problems getting the jetting right.

I installed a 140 main jet but it ran worse than with the 130 stock. I thought with the larger jet it would allow more fuel which I thought starving it of but was that the case? I've messed with the air screw and that helped but not like it should. I have reinstalled the 130. It still kind of backfires after letting off full throttle suddenly. Messing with the air screw helped but didn't rid me of that problem.

I haven't raised the needle yet but that looks like a chore in and of itself. How do I do that without taking the entire machine apart?

I currently have it where it runs okay except under a load at more than half throttle where it cuts out.

I regained some of my top speed to back to within 1-2 mph (if some of you remember my post about 2 months ago).

Help? Please?

I also have all 12 discs installed in the exhaust.

 

When you say ran worse, what do you mean? low(pilot)rpm, Mid(neddle setting)rpm, or Top(main jet) rpm? Remeber the main jet only affects 3/4 to full throttle. The air screw usually only affects idle- 1/4, the pilot does idle to 1/2 ans the neddle setting only affects 1/4 - 3/4.

 

Kind of all of the above. The air screw would help with the idle, then I'd take it down the road accelerating rapidly (full throttle) and anything over half throttle it would cut out and not accelerate. At times it wouldn't get over 35mph (top speed 54mph). Back off below half and it would run okay.

Do I need to go to a smaller jet? I thought a better exhaust increased the need for more fuel, not less.

The 140 main ran horrible so I stuck the 130 back in.

 

Sounds like either a clogged fuel filter or the float height is wrong. If the float height is to high the bowl will run out of fuel during hard acceleration but when you let off the bowl fills up again, and works ok. Check you service manaul (clymer) it will show you the exact height of the float arm. A sticky needle and seat could cause it to, but not that likely.

 

It ran fine until I changed the exhuast. Coincidence?