newbie backfire questions

[johnnybravo]

Hi, I've done a search and found that lots of you lot suffer from backfires but wanted to probe further. I've just got myself an 03 GSA (twin spark). Its fitted with a Y-piece and the standard can. I've noticed some pops and bangs on the overrun and now it seems as though the exhaust sounds a bit blowey / noisy (extra noise a problem I hear you all cry!).

Thing is I've not had it long enough to really know whether it's blowing the baffles out or not. So, should the standard can be quite quiet or is it fairly fruity. And if it has blown out some baffles is this bad news for the engine?

I got a Remus can (I think it's a Genesis - "not for road use") along with the bike that the owner had swapped back for the original to keep the noise down. Would I be better chucking that on for the time being? And if so how does it mount to the bike? Is there a clamp that goes around it? Couldn't see one in the box of bits that I got with it but will go out and have another rummage.

Anyway sorry these are pretty numpty questions but advice will be gratefully received.

Cheers,
Rob

 

[Sergeant Pluck]

My experience is that you won't get rid of the backfiring. The remus y-piece doesn't fit well, in that it doesn't go far enough over the headers to seal the little slits, leaving a gap that'll be obvious from small blasts of soot deposit on the headers. The standard can doesn't fit well over the y-piece as the y is made of thinner gauge tubing making it a struggle to get a good seal, although whilst a fiddle, you can make a 'shim' from an old can which'll help. The genesis will be much louder and fruitier, will seal better over the y but will still backfire. FTIW, I've ridden a couple of twin-sparks and reckon they've generally backfired less than my 2 single-spark GS's. The best way I found to keep your backfiring in check is to a; keep your valve clearances to spec and your TB's well balanced and b; learn to live with it!

Despite backfiring, the baffles haven't blown out on either my standard can or the Remus Revolution I had for a year or so.

Pluck

 

[pomm001]

I run an adventure single spark with Y and standard can, with the cat removed the exhaust note is a bit deeper, to my mind just right.
While a noisey can may be OK around town, i think it could get on yer t*ts after a few hours.
But i can still get it to 'pop' on the overun, i have tried about everything, most important is that there are no leaks in the system , otherwise adjust your riding style to limit, i find avoiding long periods of completely closed throttle helps, as this is when it seems to happen most.
Ther are a few threads on how to get round this, one is the 'steptoe' link that alters the fuel map slightlt by adding a jumper lead to one of the relays, didnt work for mine but worth a try