Jets

[kevin-vic-b.c.]

Have I seen recently reference to someone selling a re-jet kit for the 2nd gens?

Who, why, how much if anyone knows please.

All I see in the thread search is discussion of pro and con not sizes or why you would do this? Will this help the 2nd gen back-firing?

 

No disconnecting the AIS does not magically get rid of the back firing, there is a cause that the AIS amplifies that I need to track.

It is not: carb sync; valve adjust; AIS; dirty carbs; dirty fuel, but it could be jetting.... I think, maybe.... well possibly anyway.

 

Thanks

 

but fun

[ACE50]

So is it just backfiring on decel? Slow jets are the only thing working then. Larger slow jets? I did but for other reasons.

Don't need a rejet kit for that.

 

What are your pilots screws set at?

[Yammer Dan]

Dang Kevin with that title I was sure this had to be a thread about 1st Gens!! Have you color-tuned those things?

[MiCarl]

Unless you've modified the exhaust and/or possibly the intake the stock jets should be just fine.

 

If you're sure the carburetors are synced look for air leaks.

 

After that, the air cut-off valves. In my experience though they rarely fail.

[frankd]

Also exhaust leaks can cause backfiring.

[spike13]

http://www.ivansperformanceproducts.com/xvz1300.htm this is a custom made jet kit i used in my bike there is a huge improvement in throttle response and my after-fire went away i run la choppers mufflers and have k&n filters very happy

[V7Goose]

As I have said many times over the years, a stock RSV will NOT bang or pop on decel unless something is wrong with it. 99% of the time this is caused by something upsetting the complete fuel burn, and the majority of times it can be traced to vacuum leaks. A bad header leak will also cause it even when all else is good - that is because a header leak simply lets air in even when the AIS valve tries to shut it off during high-vacuum situations.

 

The after-fire (it is not a backfire) is simply caused by excess unburned fuel getting spit into the exhaust system, then being ignited when it is mixed with oxygen. There are always SOME unburned hydrocarbons in the exhaust, and this is one of the worst causes of air pollution. The AIS is simply a low cost passive way to allow much of those hydrocarbons to continue burning (not exploding) before they are spit out into our air. Too much unburned fuel leads to explosions instead of a clean burn.

 

The excess unburned fuel is normal when you snap the throttle closed, and that is why the AIS valve CLOSES under high vacuum conditions, to stop the flow of extra oxygen into the exhaust header.

 

But if something else is wrong that upsets the normal full burn, such as a lean condition from vacuum leak, a bad plug or weak spark, then the excess fuel being dumped into the exhaust is too high all the time, and you get the explosions happening before the AIS valve can react to the sudden increase in vacuum.

Goose