Y Pieces

[pete.keys]

advice on down pipes

hi all,

I have two types of collector that I've picked up in the last year or so

one of these g/s Y pieces

and one similar to this off a GS

For my project Katmandu bike I have decided to replace the headers as they let the bike down.

Is there any reason for not getting the g/s down pipes? They obviously don't have a balance pipe. reading some of the threads it seams like if one only has a y piece and not a collector one should use headers with a cross piece.

NB I am using the standard GS exhaust can. I presume this is exactly the same as the g/s one with the exception of external fitting and the length og the exit pipe.

Thoughts appreciated.

 

[pete.keys]

exhaust assembly paste

I took advice on this from Richie Moore who recommended the boxererparts "y" piece and g/s headers with no balance tube

hi all,

I have two types of collector that I've picked up in the last year or so

one of these g/s Y pieces

There are no gaskets, so i was planning on using exhaust assembly paste. Is this the right thing to do? Will i be able to take it apart again?

Interestingly the "y" piece doesn't have "slots" down the side to compress onto the header pipes with an exhuast clamp which i was surprised about?

Also the Y piece only slips on about 2.5cm rather than the full 5cm that it looks like was intended - anyone come across this?

cheers
-Pete

 

[Padmei]

Interesting. I am replacing my broken collector on my GS with a Y piece at the mo & was wondering the same thing re exhaust paste.
I think I'll give it a go & find out.

 

[Rob Farmer]

Is there any reason for not getting the g/s down pipes? They obviously don't have a balance pipe. reading some of the threads it seams like if one only has a y piece and not a collector one should use headers with a cross piece.

If you use the g/s collector box or Y piece then you will need the g/s downpipes because they "kick in" at the ends to fit in the Y piece (or collector) the gs pipes are shorter and straight (so you'll have a big gap between the downpipes and collector )

Anything that avoids the dreaded keihin GS Y Piece is good.

If you're doing away with a collector expect your silencer to fail before long.

 

[Redboots]

If you're doing away with a collector expect your silencer to fail before long.

Mine lasted about a year before the noise became unbearable. Nice now though with BSM can.

Cheers,
John

 

[pete.keys]

If you use the g/s collector box or Y piece then you will need the g/s downpipes because they "kick in" at the ends to fit in the Y piece (or collector) the gs pipes are shorter and straight (so you'll have a big gap between the downpipes and collector )

Aquired some Keihan g/s headers. Interestingly the aren't a great fit with the fancy curvy boxer parts y piece

If you're doing away with a collector expect your silencer to fail before long.

Why - in what way?

 

[MattW]

Aquired some Keihan g/s headers. Interestingly the aren't a great fit with the fancy curvy boxer parts y piece



Why - in what way?

I'd imagine that without the attenuation provided by the collector, the silencer will get it's innards blown to bits?

 

[Rob Farmer]

I'd imagine that without the attenuation provided by the collector, the silencer will get it's innards blown to bits?

 

[Padmei]

Ok whats attenuation?
I put a Y pipe on tonite with a R1 Ti pipe & was suprised how quiet it was - I thought it wold be much louder.

 

[MattW]

Ok whats attenuation?
I put a Y pipe on tonite with a R1 Ti pipe & was suprised how quiet it was - I thought it wold be much louder.

Attenuation knocks (or strictly converts) some of the energy out of the exhaust pulses coming from the engine. This is most obvious in terms of sound energy, but it also affects kinetic energy.

In the airheads collector box, the exhaust pulses bounce around and impinge on various surfaces which has the effect of converting some of the sound and kinetic energy into heat and also 'mixes up' the impulses coming from the cylinders (in effect the airhead's exhaust system is a 'two box' silencer). This will reduce the sound levels and give the main silencer an easier job. From what I read, the collector also affects engine breathing and carburation (probably due to the dynamics of the exhaust pulses and the scavenging effect in the cylinders?) but that's Rob's department

I'm not really surprised that an R1 pipe made your airhead quieter, it's probably designed to cope with three times (I might be doing airheads a slight injustice here ) the specific output and exhaust energy of an airhead

 

[Padmei]

Cheers MattW. I thought the engine pulses were an important part of engine tuning. Someone did explain the effect with the example of the megaphone exhausts but it's since slipped from my mind.
I did wonder what losing the collector would do to the tuning of the engine.

 

[pete.keys]

Ok whats attenuation?
I put a Y pipe on tonite with a R1 Ti pipe & was suprised how quiet it was - I thought it wold be much louder.

Hi - got any photos of the exhaust fitted?

 

[Rob Farmer]

Hi - got any photos of the exhaust fitted?

I hope it looks better than the seat

 

[Box’a’bits]

I hope it looks better than the seat

Now you've scared him off....

 

[Padmei]

I just gotta get some pics, put my suit of thick skin on & post them...sob sob...

 

[Padmei]

Here's the old stuffiness & the new hotness. The Y pipe is a Muskat model mde here in New Zealand.
There is a big difference in weight between the collector & Y pipe however not as much as I imagined between the stock muffler & the Ti pipe! The pipe is lighter than it looks.

I made a short piece of pipe up to fit between them.

God I love that seat - look at it luvverly

 

[Benjamin M]

I think that I prefer the seat

 

[Rob Farmer]

I think that I prefer the seat

.

 

[Padmei]

Well bugger you guys then - i'm going out to have a beer with Supershaft

 

[pete.keys]

for some reason I imagined using an older R1 exhaust , not one of the later under seat models.

Well done for getting the link pipe fitting ok

Exahust looks better on your bike than it does on the R1