Blown GSPD collector box

[centurion]

Hi all,
The collector box on my 92 R 100 GSPD has finally fell apart where it meets the silencer. I am looking for a 2nd hand y piece if there are any to be had pm me. Also if I fit one do I need to re jet the carbs and if so which jets and what sizes. It also has twin plugged heads if this effects the carburation ??

thanks , Centurion

 

[Rob Farmer]

The keihan y piece is a disaster and puts a big flat spot in your midrange. Boxer supplies sell a decent one.

Expect to blow the baffles out of your silencer with a y piece fitted.

 

[Belper phil]

Listen to Rob mate - i have gone the collector box route on both my GS airheads after they arrived with Y's fitted

 

[Beemerboff]

Some of the trouble can be the aluminum gaskets which BMW fitted between the three sections of the exhaust system - some times they end up in the muffler and there is sufficient heat to fuse them into one large blob, which con partially block the entry holes in the internal baffles - DAHIK.

A had a drill long enough to clear it.

There is also a baffle in the rear which can be reached with a long screwdriver It is fixed at around four spots on the perimeter and the screwdriver can be driven through section between the fixings to permit a bit more flow.

Then you will need to attack the air filter - I simply unclipped the snorkels and fitted a Unifilter foam filter , but some others who sclaim to know what they are doing cut the snorkels down 50% and drill four or five 1" holes in the top of the air box.

I didnt change the jetting but I always use the later slide spring which is a good bit stiffer than the early one.

Result, for me, was actually an increase in mid range , and a pleasing burble from the exhaust, but of course I am comparing it with a muffler which had the inlet partially blocked with a lump of aluminum .

 

[Rob Farmer]

Then you will need to attack the air filter - I simply unclipped the snorkels and fitted a Unifilter foam filter , but some others who sclaim to know what they are doing cut the snorkels down 50% and drill four or five 1" holes in the top of the air box.

I messed around with the Snorkels last year and was amazed at the difference they make and just how critical the length of the snorkels are. They effect the jetting quite dramatically around the 4.5-5k region. Its actually the volume of the tubes that comes into play. My bike was fitted with one large tube and one small, fitting two large tubes would take the jetting weak at 4.5k, one large/one small was slightly too rich. I made a wedge for the large tube that bought the voluume down slightly to bring the jetting where I wanted it. It took days of fannying about and trips to the dyno to get it right...my conclusion after all this effort. Stop being a sad git and just ride it as it is!

I wish there was a replacement out there for the standard collector box.

 

[(RIP) Arkwright]

My alternative to the 'T'/collector box piece. The difference is surprising, better low and midrange torque, better economy, (which I hadn't expected).

I too have played with snorkels after having them explained, it came with them chopped off, now back on standard!

 

[Sylvester]

My Y piece works super dooper. It was on when I bought the bike. It is shaped like an true Y not like some of the other I've seen. My exhaust hasn't blown out yet but there still time! I fancy a Zachspeed tail pipe next. Anyone tried one?

 

[Rob Farmer]

My alternative to the 'T'/collector box piece. The difference is surprising, better low and midrange torque, better economy, (which I hadn't expected).

Nice looking collector Duncan and obviously doing what a Y piece should do

 

[litelfun]

I have got some 38mm over sized headers and a y-piece I allso have a akrapovich with foot foot peg mount and allso a few with aut if any one is interested !
send me a pm !!!