OK, so.......
My 2002 EX500 is driving me crazy!!!!
(has Vance and Hines 2 to 1 and jetting)

Symptoms:
-Rough, uneven idle.
-Exhaust sounds "blappy" for lack of a better description.
-Hesitation when throttle is applied unless done very slowly.
-Engine running warmer than usual.
-Exhaust note is also a little lower than it was.
-Engine cuts out a little around 5k rpm.
-Sluggish at takeoff in 1st gear. (feels and sounds kinda "soggy")
-Overall lack of power.

What happened...
It ran great one Sunday a few weeks ago after checking battery and reinstalling
and tightening terminals. Stopped for an hour somewhere and when I started the
bike again it was suddenly running like the previous description. I know that with this
configuration it will run right. I have experienced it but for only 6 hours or so.
Oh woe is me!!!

Since then I have...
-Once again cleaned the carbs. (Yes, I took out the jets and checked every oriface)
-Adjusted the float heights.
-Traced the ignition system from battery to spark. All *seems* to be in order.
-Checked air box and air filter for possible foreign object.
-Taken off exhaust pipe to make sure nothing was clogging it.
-Cleaned out gas tank and petcock.
-Changed fuel line and installed inline fuel filter.
-Sprayed around the carb to check for leaks.
-Changed spark plugs. (again) (was using DR8's now DR9's- no difference noted)
-Redid spark plug boots.
-Checked for electrical continuity at connectors.
-Checked voltages for battery, alternator, etc.
-Made sure that diaphragms were not pinched in carbs.

I'm *almost* ready to go to a mechanic........
HELP!!!
(please????????)

 

where in your list did you clean the idle(low speed)jets? Since the bowl was off to check float levels.

 

Yup, cleaned pilot jet and main jets- again.
Also the fuel rail and the little orifaces under the butterfly.
Took the whole thing apart and cleaned *everything*.
Didn't seem to address the problem. Grrrrrrrrrr..............

 

Imagine that. A perfectly good machine "modified" and now it runs worse.
Three best options I can think of are (in order):
~change everything back to stock and enjoy your bike a long time
~change everything back to stock and buy a more powerful bike
~lay your trust (and $) on a mechanic or dyno-tuner and watch your bike die a premature death anyway because of carbon buildup on your valves, chambers and valve seals.

Sorry for not being more sympathetic, but I hope anyone considering screwing up their bike (or buying a bike that someone else has screwed up) reads this thread.
Good luck and let us know how it goes.
Peace!
-Chris in C'bad

 

If it ran well before, try checking for air leaks in your vacuum lines, and around the carb boots. Spray some starting fluid in any area that an air leak may be possible. If there is a change in idle, then you found a leak.

 

+1 on the vaccuum lines. Vaccuum leaks can cause some pretty strange results. An old dodge of mine surged something fierce at idle from a small crack in a vaccuum line. Of course I found the vaccuum leak after I replaced the throttle body.

 

Thanks for the good words!!!
I think that I may be close now. I'm gonna go put the plastic on once again.
I think that one of my float levels was a bit high. I think that my "guesstimation"
of a millimeter was a little off. However, I think that what did the trick is pulling
the cap on the pilot screw, pulling it out and cleaning the oriface there. I also read
somewhere that you should spray into the ports on the airbox side and cover the
jets so that the cleaner comes out the little holes inside the carb.
It did appear that there was some gunk in the little pilot hole, however so I'm thinking
that might be what I missed. My fingers are crossed! (which makes it harder to put my
bike back together!)

 

Oh, sprayed around the boots, too. Nothing. Bike runs better because of the extra cleaning and idle screw adjustment but still running rough. I really suspect an ignition problem. I'm gonna go back through the ignition again with a fine-tooth multimeter and see what I come up with.

 

OK, though spraying around boots yielded no change in the engine at idle, I went ahead and changed the vacuum to the petcock, rerouted the emissions stuff and plugged the other vacuum line.

Results:
the bike runs better but it still seems to be running rich. I backed the pilot screws back to 1 3/4 out and it runs a little better. It doesn't cough in the middle range any more. It also doesn't pop on deceleration thanks to the re-routing of the emissions.

It seems to be running rich but I'm running out of ideas. I pulled and checked the air box. No obstructions, air filter clean, etc. Carbs are super-clean. Floats were perfect. Boots are tight. Traced ignition again and nothing unusual found. No grounding problem that I could find, battery tight, charging good, cables good, input of coil to boot good, etc. etc. Next I will check and make sure that the exhaust is tight and check valve clearances.

Ugh!!!!!!!

 

how much bigger did you go with the jets did you chang the piolet too is it posable that the jets are to big causeing a rich condition?