My bike backfires A LOT. Is that normal?
 

Hi there

A friend of mine recently asked me why my bike backfires so much. I've gotten used to it by now, but remember that I asked the dealer at my first service if the backfiring is normal to which he replied it was.

The thing is, my ten backfires even between changing gears. Is that normal?

I bought the bike in the UK and took it home to South Africa with me when I moved back here 4 months ago. I took the bike to a local dealer the other day and asked them about the backfiring. But because the SA market hasn't received the Tenere yet, they didn't really know how to tune the engine to run leaner. Apparently on the XTR you can tune this on the console.

So is this something that I should concern myself about? Or should I keep waking up the old lady next door every time I take the bike for a ride?? :Mandy:

It's normal and everyone has it. Dunno if the ones who have tried remap have seen any differences, but I suggest you just learn to love it. =)

No Worries they all do it. blowup

I've had mine remapped.
It backfires a lot on warm up and less so when proper hot. It seems to do it less now than before the remapping.

I guessed so, the FI is set too dry from the factory to clear the emission limits and that makes the engine pop a lot more, remap fixes this. Well that's my very unqualified theory. :p

I don't think it is backfirering like in the old days but more due to the secondary air introduced in the exhaust upon throttle closure (emission control)

Backfiring
 

I have had my xtx a while now and changed pipes and dna stage 1 filter. I increased the fuel mixture to compensate this but still it backfires. It was suggested I give the bike a good run and check the spark plug as soon as I returned home. I have done this, the plug is bone dry with no discolour (recent new plug). I have incresed the fuel mixture another 5 today to see if this assists with the backfiring and makes the plug look a little healthier.

Kev has designed a fuel mod which seems to go down very well with others here on the forum, ive had other mods but not this one as I dont quite undersatnd it however it may well be a way forward.... Dave

Its not a question of remapping the Fuel Injection system.:018:

Its just the A.I.S. (Air Induction System) that causes this popping, in order to reduce the emission of hydrocarbons.

There is a reed valve that opens , when there is negative pressure at the exhaust port, allowing secondary air to flow into the exhaust port.
If the temp is high enough ( 600-700 C ) the unburned fuel burns (explodes) into the exhaust , causing the pops and the bangs.

There is a way to fix this if you want, though not very legal (at least where i live).....
Ask your dealer :whisper:

Snapping the throttle shut when changing up can produce a backfire. With practice you can do in on demand, I recommend tunnels and underpasses.

As Microsoft say - it's an undocumented product feature.

Si

I must admit I would miss it if my Ten didnt do it now. just need a loud pipe to really enjoy it. a couple of options are a remus pipe I had for a BMW 850 and my CRD pipe from my TTR 250 but either will mean some handy pipe work.

Your bike is NOT backfiring, she is popping, backfiring is(was) when the unburned mix at the carb was able to ignite and explode back too the air filter.

As Andy12 says, the popping is due to the AIS, there are 3 ways to stop the popping.

1. blocking the AIS intake.
2. removing the AIS completely and tapping the AIS hole at the head and the air filter hose.
3. keeping the AIS valve closed all the time, you need to connect the AIS valve wire to ground, very easy to do under the seat, but you need to cut the brown/red wire and connect the non-ECU end to ground.

have fun,

j.

The AIS is controlled by the ecu but also like mentioned here before it will open

Considering your Avatar, it's good to see you here.
I always enjoy your inputs at Fullgaz.

Sorry if I'm wrong.

You got me :sbike:

I removed the AIS plumbing last week - fitted a rubber bung in the airbox hole and made an alloy plate to cover the inlet between the manifold - and can confirm this has all but cured the backfiring you experience when snapping the throttle shut...

Fortunately the ECU does not flag up a fault code if you simple disconnect the AIS solenoid plug - there is a routine on the diagnostics to test the solenoid is working, but not an actual fault to say it's not (I trust Yamaha knew people would probably want to disconnect this, so made it easy?) - result!

Once you have blocked the two holes, you ought to have no problems, and no popping!

xxx

This is now on top of my to-do list. Then I can put back my slip-on, the backfiring was deafening with it on. =)

My XTX does this a lot; I have to say though that it doesn�t really bother me, I actually quite like it.

One of those strange fetishes that we all have I suppose? :eusa_shhh:

It is reassuring to read that others have the same though and it does not indicate a 'problem'.

Me 2.