After rejetting (128 front carb and 132 rear carb) w/ twinair and snorkle mods, I noticed my 650 backfiring when in reverse. I was stuck trying to shake the machine loose enough to get some bite and pull out of a mud hole on it's own and noticed that the quad backfired about 6 times in the time I was trying get out (about 1 minute). It seemed to happen when it hit the reverse rev limiter and I stayed on it without hitting the override button.

Is this any indication that the quad isn't jetted correctly? Is there something I should do to fine tune it?

 

Mine backfires a little too when I hit the rev limiter in reverse, I have stock jets, I do not think you have anything to worry about.

--ray

 

Just to make sure that I am straight on this.

You reversed, but you didn't hit the override?

I don't think you have an issue, unless you are talking about another sound, this is the machine kicking in and out because of the limiter on it and not backfiring, I have done that plenty.

Forgive me if I am mistaken about your situation.

 

That sounds like the limiter. You are still sucking and pumping fuel, just not burining it on every stroke, so it hits the exhaust system where the next firing impulse lights it off...

Would be dandy if there'd be a settable limiter so one could still maintain a safe limit, yet not so low.

FYI, the Polaris back fires too when on the limiter.

 

It definately backfires, fairly loud too.

Funny, I never had it do this before I jetted it.

I didn't notice it doing it at all when I hit the over-ride button.
Wasn't paying attention to much...just trying to get out of the mud.

 

To the best of my knowledge, w/o using the override button, the timing changes in order to keep you from going any faster and that is what eventually leads to backfiring. I am pretty sure it is something along that line. Have 2 quads with the reverse override.... both WILL backfire when you don't hold the button down!