Backfiring of the 796 - any suggestions?

[HyperDesmo]

Hi to all,

I´ve got a question concerning the 796. My one ist still in the break-in phase. The engine backfires like a big-bore single and lacks the classic desmo-sound you expect from a 800 cc engine.

So three questions:
1. Will the backfiring get better with higher mileage?
2. Will the engine run like a desmo with the Termi-silencer in combination with the ECU?
3. Will the engine rund like a desmo with the Leovince silencers (Think it is a popular silencer in the US)?

Thanks for any advice!

Cheers, Marc

P.S. - How high should the engine run in idle running, my one is at 1200 rpm according to the rev counter!

[stuntrider7x]

Backfiring will not go away unless you change to a performance ECU because the stock one is lean, Adding any aftermarket silencer without eliminating the Cat is a huge waste because the cat absorbes most all that great desmo sound and If you are curious about me saying that take off your stock silencers and start the bike you will find its not loud at all with no silencers.

What you need to do is get yourself a full system if you wanna hear the true sound of that sweet twin, Im running a LeoVince Cat Eliminator with a custom mounted FMF Motocross bike silencer with stock ECU, My bike does backfire on decel but not enough for me to worry cause my airbox is also Stock.

[damienvall]

great pic of your bike! Are those indicators and license plate mount stock parts or did you fabricate them? Have wanted to set mine up that way since I got it.

[stuntrider7x]

Thanks, the signals are stock and I fabbed a basic bracket for them and the licence plate.

[ducatiwop]

Originally Posted by stuntrider7x

Thanks, the signals are stock and I fabbed a basic bracket for them and the licence plate.

Love the bike, I've been wondering about doing an fmf type of pipe with cat eliminators. If you don't mind me asking, what bike was the pipe designed for and how does it sound?

[stuntrider7x]

Its off a 2007 KTM 250sxf, I cut 7/8ths off the LV were the mid pipe connects to lower it so fmf would clear subframe then cut the mid pipe to correct lenth and fabbed a basic bracket to bolt the pipe to sub frame.

The FMF I have on is a Q so its a tiny bit quieter but man does it sound good and everybody that I ride wit comments on it, Also im a big dirtbike guy so the single FMF gives that Motocross look that I like.

[hoveyh]

First order of business is buy a LV or Arrow Cat elimnation kit and try it.... you Will Be Amazed .... check my posts in this forum about my bike. Mine pops no more than stock.... which was plenty on deceleration.

HH

[ducatiwop]

Originally Posted by stuntrider7x

Its off a 2007 KTM 250sxf, I cut 7/8ths off the LV were the mid pipe connects to lower it so fmf would clear subframe then cut the mid pipe to correct lenth and fabbed a basic bracket to bolt the pipe to sub frame.

The FMF I have on is a Q so its a tiny bit quieter but man does it sound good and everybody that I ride wit comments on it, Also im a big dirtbike guy so the single FMF gives that Motocross look that I like.

Thanks you so much

[HyperDesmo]

Okay, to put everything together:
1. Backfiring can be adjusted by a different ECU like the one from Termignoni, by a PC or by a FatDuc
2. Sound can be improved by eliminating the cat (See cat eliminator thread!) and the silencers as I think the stock silencers with cat eliminator wil make things (sound) worse.

So - thanks for your opinions!

P.S. On my enquiry concerning a FatDuc O2-Eliminator for the Hyper 796 I received this Answer:
"Hi Marc,


At this point we do not have a solution for the new Hypers, but we're actively testing various configurations and hope to have a product released soon. I'll save your email and notify you if we're able to find a solution."

[minusone]

I have found with other bikes, abnormal backfiring on decel can be caused by an ill fitting exhaust or header that allows air to get in.

Also lean mixtures on my KTM caused (popping and farting) until I got richer mapping to suit the pipes.