Bonneville America Forums Forums Technical Forums Exhaust Pop at desceleration

hello all,

because I thought my exhausts (tappered ones) were not loud enough, i drilled some holes ...

Now it sounds good but lot of pop when decelerating.
My bike (America 2009 EFI) is already remapped with the TOR map.

Is there any tip to avoid that poping , please ?

Thanks for advices.

Did you create any exhaust leaks when doing the drilling? That could do it. Afraid I'm not much help on the EFI bikes.

I just drilled the plate (disc) that is at the end of the exhaust. Just near the big tube inside. (I don't know how to explain)

Bonjour Tfrenchy.
I am English but live in Vienne. We sometimes visit La Rochelle so it would be good to meet up for a coffee sometime.
Gary.

Bonjour Thierry.

I hope your diagram explains, I think you only removed A.
[image]http://www.yogourtnoway.com/forum/download/file.php?id=83[/image]

Bonjour mate.

All Our EFI Triumphs pop when decelerating ... IF the AI is still intact and the O2 sensors are still operating. You must disable them to stop the popping.

The pop usually occurs in the headers when the computer tells the AI to pump more O2 into the fuel mix on closed throttle to deliberately ignite unburnt fuel detected in the headers.

You have drilled a hole in your rear baffle and the popping sounds much louder and you're noticing them more. Drilling the baffle won't make it pop any more or less.

There are several threads on eliminating popping. Try searching for EFI and AI elimination and Popping.

I have an 09 EFI as well and still have some popping after changing exhaust and having the richer EFI map downloaded.

+1 to Foglefar, the air injection and O2 sensors are causing the unburnt fuel to ignite. there are instructions downloading new EFI maps that will also disable the O2 sensors here.

http://www.bonnevilleamerica.com/forums/...part=1&vc=1

Air injection removal must be done mechanically. Also, there was some discussion a while back about European vs. north American triumphs as to the presence of a catalytic converter in the header pipe. Supposedly the euro bikes have one. might want to look into it before making too many changes.

cheers

its a Triumph thing...i love it!

Sure, You welcome !
Just send me a PM when you arrive there I'll be happy to meet you

Ho, I forgotten that !

Well , I just retrieved the B tube, and now I've drilled around tube A (near the red point 2) . I just made 2 holes there.

Thanks Stephen (nice to see you again )

Ok, all

Thanks for advices.
I'm going to take a look deeper in the forum about AI and pop stuff.

Here EFI 2009 bikes have catalytic converters, so I'll be precautious now. (Not to completely destroy the bike !)

Plug the inlet hose between the air filter box and the air injection valve and see if it goes away. If so, the Secondary air is the culprit.

Disable or remove the AI should help. With less restrictive exhaust you will have some popping on deceleration even if the A/F is perfect.
They put the cat in the headers in Europe? Not in the front end of the pipes?

I know there is talk of cats being in the headers in Europe but I find it hard to imagine that there is enough room in the header tubes. It seems far more likely and practical that the cats are in the front of the mufflers(silencers) as Dogg33 says (and that's where they are in the Australian bikes).

It is a characteristic of high performance engines. It was always there, the stock silencers just hide it well.

By all means, eliminate the air injection, it contributes to the popping and causes the head pipes to overheat.

I love the pop....

I just put my Chevy605 pipes on my Speedy '09 and love the popping too.

Should I still have her remapped to aftermarket? Dealer will charge me $80.

Is the popping bad for the engine?

Thx

You should remap if the pipes are freer flowing than stock. Otherwise you risk running too lean/hot. The bikes are lean out of the factory. You will also likely get a performance improve.

The pop in an EFI is intentional as the AI explodes unburnt fuel in the headers. No damage done. Not to be confused with get a backfire through the airbox which can shatter an airbox and probably do other damage as well.

So, the only downside to the pop is the header getting hotter than normal, and bluing of the pipes can result? I'm also a fan of the popping, its part of the character of the bike imo...

Depends how lean you are and how much popping you have. Some is good, if jetted or mapped right you should have some but if it is excessive you may be lean enough to burn a valve.

As Ian said, "some is good". If you open up the exhaust and set the bike up right, there should be some popping. If you work to eliminate it, you can defeat some of the advantage of greater air flow.

After I had mine set up right, I did have an instance where the popping increased noticeably. It turned out to be my header bolts needed tightening. Any air leak at the engine end will increase popping.