Backfires

pall138 · Posted: April 2, 2008, 7:58 pm Post subject: Backfires

I have a 72 and just put on the new pod filters mikes sells. I rejetted and it seems to be running fine, but it backfires on deceleration a lot more than it did before. Should this be expected or do I not quite have the jetting right? Its performing well and the plugs look good, I just hate it when it makes “new” noises.

xsjohn · Posted: April 2, 2008, 9:50 pm Post subject: Re: Backfires

Throttle off decelerating.....it's working off the pilots........try playing with the mixtures screws if you haven't already......?....less restriction on the intakes if that's the case will change everything......too much on the mixture screws and the plugs will have lots soot on the outside plug ring.....no soot probably lean .......just a trace of soot onthe end of my fingert is what I look for.....hope this helps.......

And new plugs seem to take longer to show the soot.....I use older plugs for that test......and about 5 miles of somewhat easy throttle......

xsjohn

5twins · Full Member Joined: Aug 05, 2006 Posts: 1616

When you say you rejetted, what jets did you change? Did you go up on the pilots? If not, you may have to. And as John said, you'll need to reset your mix screws as well.

TeeCat · Posted: July 1, 2008, 10:06 am Post subject: Re: Backfires

Found this interesting. Anyone seen it before?

TC

raftercliff · Posted: July 1, 2008, 1:32 pm Post subject: Re: Backfires

That article is interesting. It's useful information for a novice like me. If I understand my bike correctly, the spark doesn't retard when the throttle is closed but the rest of the info certainly applies. I do have to say that since I tuned my carbs according to xsjohn's advice, the popping has gone away while performance and mileage have improved.

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