Backfire

[Comfy Old Boots]

03 r1150 GSA, with standard can and ypiece. The bikes backfiring past the collars that connect the ypiece to the down pipes. I've adjusted the collars but it's still backfiring on roll off. I've read here you can't use silicone to seal them due to the lambda.

How can I seal the pipes and is it bad for the engine to leave it as it is?

 

[sproggy]

The bike is backfiring out of the end of the can, not at the joints with the y-piece. But it'll probably be air leaks at those joints making the backfiring worse than normal and the leaks will be identified by carbon deposits. Right?

The problem is probably because there's not enough overlap between the two pipes. When I had this problem with a Remus item I removed the y-piece from the bike and (using a large hammer and block of wood) 'adjusted' the mount that attaches to the centre stand mount backwards a bit. This allows more overlap between the pipes (y-piece and downpipes) while still having the mounting line up. A bit of trial and error is required - a little movement at a time.

This solved the problem completely in my case.

If you're worried you can use a little exhaust paste on the joints but this shouldn't be necessary.

 

[Comfy Old Boots]

The bike is backfiring out of the end of the can, not at the joints with the y-piece. But it'll probably be air leaks at those joints making the backfiring worse than normal and the leaks will be identified by carbon deposits. Right?

The problem is probably because there's not enough overlap between the two pipes. When I had this problem with a Remus item I removed the y-piece from the bike and (using a large hammer and block of wood) 'adjusted' the mount that attaches to the centre stand mount backwards a bit. This allows more overlap between the pipes (y-piece and downpipes) while still having the mounting line up. A bit of trial and error is required - a little movement at a time.

This solved the problem completely in my case.

If you're worried you can use a little exhaust paste on the joints but this shouldn't be necessary.

Hiya sproggy. That's seems like a good idea. Reposition the ypiece a bit. Incidently, it's blowing out of the ypiece/headers join! I'll find a pix hang on...

 

[Comfy Old Boots]

pix

also, any ideas on how to get a seized lambda out of the ypiece? tied plusgas, a hammer, spanners, swearing etc

 

[davegs]

I removed one for a friend when there was not much left of the nut with a pair of steelsons, not a prob came undone straight away and went back the same way. So don't scoff DO IT.

 

[sproggy]

Incidently, it's blowing out of the ypiece/headers join! I'll find a pix hang on...

Yes, that's where mine was blowing, but the air that gets in those leaks on the over-run causes backfiring from the can.

As for removing the lambda sensor you could try heating the area of the Y-piece around the boss which should help undo it, but why do you want to remove it? Far easier to unplug it - the plug is against a frame tube under the right hand side of the tank, with the wire running up behind the right hand cylinder - and leave it screwed in to the y-piece.

 

[Comfy Old Boots]

Thanks lads. Believe me Davegs, I've tried to get it off! I'll just take it off at the connector. Seems easier to do. Btw, I bought a stainless steel polisher for my drill and was hoping to buff up the down pipes. Pure vanity I know but I like it dirty too and I'm trying to pull her back from the bit of decay i'm noticing since I washed all the winter grime off her.. (it stayed like this for a month or so)

 

[Comfy Old Boots]

and sorry about being pedantic but is this not an explosion?! I think I've sorted the side in the piccie but the other side I can hear when I'm riding. Anyway, thanks for the pointers. If i remember correctly, the ypiece is too short but the last time i looked at the join to the can. I'll pull of few bits off.

 

[Comfy Old Boots]

stupid computer. if i the time uploading these pix on the bike i'd prob be done now!!!

 

[sproggy]

If i remember correctly, the ypiece is too short but the last time i looked at the join to the can. I'll pull of few bits off.

The position of the can can be adjusted (loosen the bolts holding the bracket to the can itself) but the downpipes can't so you have to make everything fit relative to the downpipes. First get the overlap correct between y-piece and downpipes and then worry about the joint with the can afterwards.

 

[Comfy Old Boots]

The position of the can can be adjusted (loosen the bolts holding the bracket to the can itself) but the downpipes can't so you have to make everything fit relative to the downpipes. First get the overlap correct between y-piece and downpipes and then worry about the joint with the can afterwards.

Right I'm back to this!

I've reread this (without beer)

A number of things. To get the join right between the downpipes and the can correct, the can ends up about a half inch too far away from the securing mount on the frame. I.e I can't secure the can to the frame. So, I've decided that I need to find a bit of metal, shape it and drill it and support it that way. That'll make everthing fit.


The other problem I mentioned about the bike ages ago was the fact the can kept comming loose on spirited riding over bumpy things and that I'd secured it using feeler guages. Well, the problem there turned out to be a lack of torque on the relevent securing bolt. It kept comming loose at 42 Nm (correct setting if the y piece/cat is the correct width) but I tightened it tighter and it seems to be holding perfectly for the first time. So that's one problem sorted!

Just going through old problems I've had folks and trying to put a resolution on them for anyone who's checking my threads afterwards. I also just want to get the bike sorted once and for all and not be faffing round with temporary fixes. Procrastinator extrordinaire here.

Now. I must look for a bodgeable bit of metal and if I get it right, I'll have a beer

 

[sproggy]

I'm sure someone will correct me if I'm talking complete cr*p but isn't the position of the mount on the standard can adjustable? Not having the benefit of an 1150GS in the garage I can't check this, but I'm sure that if you loosen the bolts that hold the bracket onto the can you can move it a bit - may be enough to line up with the hole on the footrest bracket? If not, try elongating the holes a bit more - surely better than making up another bracket.

 

[Comfy Old Boots]

I'm sure someone will correct me if I'm talking complete cr*p but isn't the position of the mount on the standard can adjustable? Not having the benefit of an 1150GS in the garage I can't check this, but I'm sure that if you loosen the bolts that hold the bracket onto the can you can move it a bit - may be enough to line up with the hole on the footrest bracket? If not, try elongating the holes a bit more - surely better than making up another bracket.

I'll have to check but I think I need more wriggle room.

here's a picture

I could drill the yellow holes in the existing bracket to get the distance I need but I was thinking of making something like the yellow oval instead. If the bracket dosn't work I'll get a sleeve made up.

 

[Comfy Old Boots]

Bracket made and fitted. No backfire. Sounds much nicer. Angle is slightly different so I'm hoping it will stop melting my indicator as an added bonus!!