fitted y-piece : help please

[_pi_]

Recieved y-piece on saturday - spent 2 hrs with it and autosol and now it looks nice (bought on forums).

scanned forums for advice. bought firegum (i think it is called from halfords) to help with fitting. sunday print out manual pages on exhaust assembly (thx for links) and remove can, cat and oxygen sensor. nice and easy as my bike is only a year old.

fit the y-piece with oxygen sensor, smeared exhaust header pipes with exhaust paste and slid in in place. would have thought i would go on further but the mounting thing underneath meant i had to pull it back a bit. tightened the mounting bar (with those funky bolts), smeared a bit more paste on the joint and slid the original BMW clamps back on. bit of a loose fit after tightening ... how tight should it be? no rattling but i could rotate the clamp after tightening.

smeared original BMW exhaust with the exhaust paste and refit the exhaust.

fire it up... sounds better already! take it for a ride and pop goes the exhaust on overrun.

couple questions:

- how tight should the clamps fit - are they doing the job of sealing or is the exhaust paste?

- i tried to remove the spacer from the clamp (with it on the bike) but had not luck - can it be removed? or should i buy new clamps. I seem to recall "The Mechanic" suggesting M&P stainless clamps - what size do you recommend "Mechanic"?

- is the poping happening because of a leak in the header joint or the joint with the can? can you tell? or can it not be avoided

- the oxygen sensor was covered in soot - is this normal? i brushed it clean before refitting.

Do i need to pull it all off and start again?! Or do i just need to fit ew clamps? Or can i remove the spacer?

I would like to avoid the popping/backfiring as one post suggested it could lead to premature burning of the valves.

Help please!

 

[Dave Hall]

The original BMW clamps are not a good fit with aftermarket pipes. I cut some sleeves from a peice of tin to fit between the clamps and the pipes and that seemed to do the trick.

The remus clips supplied did`nt seem up to the job so I kept the OEM items.

 

[_pi_]

The BM clamps are too large - gauge on cat versus gauge on Y piece. Normally new, lighter clamps are provided.

Soot, (carbon)- is normal - shouldn't really touch the probe.

You should not, (I didn't), need firegum etc, (exhaust paste?) - nothing is best, (clear silicone - second best) - any grease, oil, and especially WD40 is not good as when it heats carbon deposits stay on metal surfaces and make it difficult to remove them in the future.

Unless you take it all to pieces again you will have to bend BM clamps to get them off and new clamps to fit them - which is not a great thing to do


Para

any problems with backfiring?

ahh.. so the remus y-piece is smaller gauge but same inner dimensions on the front end and same outer dimensions on the back end as the CAT? that would make sense that the leak is in the front as the standard BMW clamps don't go tight enough.

Assumably since the can goes over the y-piece at the back then the fit is fine with the standard clamp (and can)? Im hoping so as the exhaust cover for the bottom is welded to the BMW clamp.

thx.

 

[_pi_]

I do not have any problems with backfiring
I fitted a Remus Y piece and Remus can at the weekend and have ridden about 150 miles since fitting.

The Y piece onto the BM front pipes was a tight fit - block of wood job - slow tap by tap procedure to line it up so that the bolts that go into the centre stand brackets went in OK.

If it is backfiring you probably have air getting into the system or a mixture problem, (shouldn't have - unless you had one before).
Presumably - the sensor went back OK

As you say rear clamp is OK and fixed to the original cover - not much room

Sounds as if you only need to replace the forward clamps. I would try the "lighter ones" or Dave's solution.

If you have a leak - you should be able to "feel it"



Para

great response... thx. i bought the y-piece second hand - so i dont have a set of "lighter" clamps. care to sell yours?

bike did not backfire before. ill try to feel for a leak but suppose i won't necessarily be able to feel it (it might be on the engine side).

 

[Les Wassall]

I had to knock the spacers out of the clamps for them to fit, no problem after that, not even a backfire.

then I found out the Lambda probe was u/s

New Lambda, backfire when you roll off the gas at speed, great sound and my mpg is up

 

[Deleted Member]

silly con...

I was told to use bathroom silicone sealant and although I thought it would just melt and make a mess I must confess no melting and no back firing!

 

[Les Wassall]

when the sensor went - what symptoms did you get - just interested - I do not have a problems

At first I thought everything was ok, the bike was going better but it did not backfire, which I thought I had sealed all the gaps, then the mpg went very high, put that down to more throttle, when it went into Williams for some work and to check the fuel they spotted it and replaced it, after that it poped and farted but bike went like stink, and mpg was back to nearly normal

 

[robb]

great response... thx. i bought the y-piece second hand - so i dont have a set of "lighter" clamps. care to sell yours?

bike did not backfire before. ill try to feel for a leak but suppose i won't necessarily be able to feel it (it might be on the engine side).

You can get stainless clamps (43mm to 47mm) from M&P. They do the job at the front and are much shinier than the originals.
Lots of WD40 and a Manchester screwdriver will get the spacer out of the rear clamp.

 

[_pi_]

"popping" is different from "backfire"

Which do you have?

any flames?


Para

im not sure but it is unpleasantly hot to hold my hand about 3 inches from the exhaust when i pulled up to a light. I had not tried this before but only a v short (less than second) exposure made my hand uncomfortable/hurt - i was wearing GS type offroad gloves (not leather on the whole back of hand).
having said that i notice a distinct difference between the rather consistent series of pops on overrun vs a good loud (backfire?) bang. the bangs can be avoided by pulling in the clutch at 2k rpms.

might sound like a silly question but should it sound much different? it does sound deeper and more thumping at idle (me likes) or is this gas escaping somewhere other than the exhaust outlet?

 

[_pi_]

You can get stainless clamps (43mm to 47mm) from M&P. They do the job at the front and are much shinier than the originals.
Lots of WD40 and a Manchester screwdriver will get the spacer out of the rear clamp.

thx v much. i was wondering what size to order... and thx for the tip/encouragement on the rear clamp.

one more question robb - did you use exhaust paste or was removing the spacer and using the m&p clamps enough to avoid the popping and backfire?

 

[robb]

thx v much. i was wondering what size to order... and thx for the tip/encouragement on the rear clamp.

one more question robb - did you use exhaust paste or was removing the spacer and using the m&p clamps enough to avoid the popping and backfire?

I used holts exhaust sealant as well. I used an M&P clamp and sealant at the back and never got any backfires but it didn't look as good.
I've gone back to the original rear clamp with the spacer removed and used the sealant as well. I think it still leaks a bit but it only backfires now and again and more often than not it scares the crap out of a car driver or pedestrian so I have a giggle about it.

Next try will be the original rear clamp with silicon sealant when I can get off the thing long enough for it to cool down.

 

[_pi_]

what type of silicon sealant can withstand the temperature?

 

[Les Wassall]

sound

The sound of the exhaust note is a little deeper with a y-piece, much better

Silicon is heat resistant; I always go for the best quality one.

 

[doubleR]

Silicon

Have used it for years on racing 2 strokes, where the header pipe goes into the barrel. Best reults from the clear silicon, white seems to breaks down more. Make sure all surfaces are clean (use brake cleaner or similar) before applying silicon. Also ensure old silicon is removed with a sharp blade if refitting.

 

[carlhowe]

Being a pedent, I thought I'd say that none of you have used Silicon to seal your exhaust systems. Silicon is a gray/black brittle element blah blah blah.

You have used silicone. Which must be okay at high temps since I have used it to refix the 'rope' seal around the door of a wood burning stove and it works a treat.

ta ta
Carl (the chemist)

 

[Dave Hall]

Screwfix sell a high tempreture silicone sealer £3.99

 

[Sergeant Pluck]

i bought some silicon sealant from halfords which hasn't melted or anything... it's also bright orange and looks crap so make sure you get the clear version! having said that, i've refitted my system four or five times now, both with the original end-can and a remus, and i've never been able to stop it backfiring completely - and i'm convinced it isn't leaking air anywhere now.

pr0ne

 

[GLURU]

fitted y piece

just for infomation general silicone sealeant will stand a continious temp of 250 c

i to have just fitted a y piece and end can with no probs (20 mins )
i used the bmw clamps ran the bike once and then retightned no leaks

 

[littleredrooster]

...... i've never been able to stop it backfiring completely - and i'm convinced it isn't leaking air anywhere now. pr0ne

Yup, I agree completely on both points.