New Exhaust and Backfires
 

Have got a K3 and have recently put a 3/4 Gforce exhaust on to replace the standard can. While the sound is now much more like it :twisted: I get quite a lot of backfiring when I roll off the throttle. This is all well and good for "shooting" old dears with, but is it damaging my engine?

Even if it isnt, Id like to stop it, or at least reduce it. How can I go about this? Any ideas anyone? Would rather not go down the £300 Power Commander route if poss for the obvious reasons!

Check that you have no leaks in the exhaust. I had this problem when the exhaust was broken on my GPZ (espcially in the cold). Air entering the exhaust expands rapidly causing the bang. (At least that's what I remember). I was warned that it *can* (ie not will) cause heating to the cylinder head - but maybe that's just becuase that's where one of my main leaks was...

Stu

It's caused by air getting sucked in through small leaks in the pipe work and then fired back out. It's very hard to sort but you could try some exhaust putty or something. I've learned to live with mine. :twisted:

As for PC, I don't think it will cure backfiring but might make your bike run better with the new 3/4.

Bloody hell Baz, did we hit submit at the same time?

Stu

Cheers guys. I know the clamps I used were a touch too big. Ive got some smaller ones now and will try them to get a tighter seal. Failing that, where can I get exhaust putty from? Somewhere like Halfords sell it?

If that doesnt work, any other things to try?

Halfords should sell it. 'Fire Gum'. But be warned it can be messy as hell, and if you have to lay it on a bit thick it will crack... Used it (lots and lots of it) to keep sealing the exhaust on the GPZ. Sealing? Sorry rebuilding... :shock:

Stu

For what its worth ( and I am no expert)

Did you re map the ECU when you fitted the system ?

Without the Power Commander and full dynotune, there is a Suzuki tool that remaps the ECU at 3 sites. I was informed of this when my can/ K&N was fitted. Not as precise and exact as a P.Com. & dynotune with over 100 map sites but still required when "rebreathing" the engine by way of new exhausts etc.

My mechanic road tested the bike and one of the things he looked for was popping and backfiring.

Don't get the exhaust repair stuff, too thick- halfords do a silicone liquid gasket that's designed for exactly this sort of application, works a charm.

Hang on, if it's a 3/4 system, did it replace the rear downpipe? CXould be you just need new gaskets at the "breaks"...

Backfiring while rolling off throttle often means that the fuel mixture is too lean. With fuel injection, you would have to re map or use a power commander to sort this out. If the lean situation is excessive, it could cause engine damage in form of a burnt exhaust valve I believe. Best to check with a mechanic.

vtour

Mark,

I used bathroom silicon sealant / mastic on mine and it works fine. If you have got some kicking around just use that. Only need a smear round the joints.

No - rear downpipe hasnt been touched. The new exhaust just slips on to the downpipe from the rear cylinder and clamps up to it.

Done no remapping at all. Its all still standard in that department. Also, not fitted a K&N etc either.

If I do need to have this Suzuki tool thing done, is it a main dealer job or can any bike mechanic do it? Whats the cost involved?

Ah right, it's a K3 isn't it. So there's not a gasket where the old pipe came off and the new one joins?

My guess is you need a Suzuki bike mechanic to do it as they are most likely to have the Suzuki remapping tool.

Cost - costs nothing to ask them if they can do it and what they will charge if it is required. (My cost was part of supply & fitting of the Scorpion - $500 NZ dollars total plus $200 NZD for 6000km service) A bargain INMHO.

Nope. Even the original pipework just clamped on with an allen key type bolt. Pretty esay really.

Bugger! Mines just had its 6km service a couple of weeks ago too! Oh well.... Cheers Shooter

Ah right. The '00 pipe is the same at the rear cylinder (a short pipe with a gasket, which attaches to the actual downpipe by a wee allen bolt) but there's a gasket where it breaks at the bottom, near the collector box.

On the 03 pipe, its all one welded unit as far as I can see.

Blue Flame
 

Whille your on the subject of exhausts as anyboby tried an Evo Blue Fame and if so are they any good :?: :?:

Then how does a 3/4 system work for it? Maybe I'm being dense...

For the original bike, it's in 3 bits- there's the rear downpipe, can, and collector box in one part, the tiny wee bit that goes at the top of the rear downpipe (which is where one end of a 3/4 system would go) and the front downpipe. Usually a 3/4 system would replace the whole back half and retain only the front downpipe, but there has to be a link where the front downpipe and the rest of the system somewhere, and on the old bike there's a gasket in there.

CAN-
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-[_ and _

(ah, rubbish ascii art, it's like the future never happened.(

Re: Blue Flame
 

Amarko5 amongst others has one and it sounds awesome, but theres various reports about customer service or lack of it. Have a search through the threads and you'll find loads about em.

Not at home at the moment so cant check the pipework so this is just from memory, but as far as I recall, theres the front downpipe with a gasket to the enginey bit (not very technical or mechanical - sorry!). From there, its just one whole piece that slips on to the front downpipe. It has the small pipe that slips onto the pipe from the back cylinder and both of these just clamp on, and also the can. The can is welded on so has to be cut off.

The 3/4 system just replaces everything EXCEPT the front downpipe. It just clamps on to where the stock system clamps on but you can also remove the can as its just a slip on on the new 3/4 system, so can be swapped for something else at a later date if preferred.

Hope that explains it a bit better. If I was a bit more technically minded I could explain it better I suppose :?

Aye, that's what I'm meaning. On the original bike, there's a gasket where the front downpipe meets the rear bit.

Ah, right. Nah, not on the K3. Its just a clamp. Wish it was just a clamp for the can too though so you dont have to mess about either cutting or getting a 3/4 system, but thats another story.

I know, it's crap isn't it...