Carbuereter backfires on "de-accelleration"

[rhandw69]

Im trying to make sure my 416 is dialed in correctly. I have the E series slip on and the xr cam.
Now i have the 42 pilot, 175 main, no airbox, k&n, and clip in the middle.
Now,
Heres the problem,,,if it is a problem.

Naturally it pops when it is cold. Now once it warm it pretty much quits. Now when riding, my top end pulls good. BUt what i notice is when i decellerate,,,it pops and backfires a bit.
So usually what causes this,,,is it rich or lean,,,and where at,,,the bottom mid or top??? Or is this just normal?
Thanks"de-accelleration"

[big-guy]

I'm not super familiar with the inner workings of a 400 carb, but when you let off the gas, the sudden resriction of the airway causes more fuel to flow through the low throttle passages, temporarily enriching the mixture, a lot like using the choke.Since the throttle is closed, changing the main jets will have no effect, but I'm not sure about the pilots. If you smoothly roll off the gas, it shouldn't pop and crackle. Anything with a performance carb will do this.

I think the stock carb is a constant velocity type though, which shouldn't do that, I don't think. Somebody here should know more about it...

[ATVer14]

I have the same problem, and I thought that it was caused by a lean idle mixture screw (the one closest to the engine). When it gets warmer out, and I put my pipe back on, I'm going to try and richen this mixture and see what happens. Just my 2 cents.

[RAPTORAZ]

Popping on deceleration means it is lean on the main jet. Keep going up two jet sizes at a time until it revs down smoothly. We are talking about it popping right after you've gone W.O.T. right?

Also raise your needle up 1 notch,,move the clip down,,you could be in the lower/middle part of your carbs circuits..are ya WOT then backing off and hearing it,,like raptoraz mentioned.. Wear exactly is this happening?? :confused:

what's your elevation,,,175 main seems like it should handle it. I"m at sea level and run a 165 with the almost same setup.

[knighttime]

Move the mofo down one notch. Check out my settings below. Mine's jetted good I think.:confused:

[rhandw69]

Well im at pretty much sea level here in washington. BUt yes afte WOT is when it does it. Im going to have to put a larger main in once i go to the dunes. For some reason at that level, i tend to run lean. Of course that is rite on the ocean.
Im going to lower the clip and then try it before putting in the 180 main jet. My Plug actually doesnt seem to bad. I had a friend read it who told me its about rite in the middle of where it should be. (whatever that means!!!)