Exhaust downpipe to head connection

[ukjules]

I have the following setup for my downpipes.

Bike = GS550ET 1980

I am just finishing off a head rebuild and again I come to the 4-1 exhaust connections
and assembly into the head.

Can you get different connectors as mine simply are too tight ? they always have been.
Note- update - i have changed heads - this head might be slightly tighter than my old head ? see spec at bottom

I dread doing this as i have to use a metal bar and hammer to force the rings into and agaist the gasket ?
I mean the connector that hold the pipe to the gasket (bit in the middle) and is
then held by the exhaust clamp with two bolts.

Is this normal or have i got something wrong ? I bought the bike like this.
It really is too hard to put back so i must ask as i cant go through hitting the rings with a hammer for hours
to make this fit.

Do other exhaust behave like this ?

Head exhaust outlet - 36.3mm approx
Exhaust downpipe ring - 36.7

[ukjules]

I think this is an issue for motad - will call em.

Question:
What is the experience of 4 into one exhausts ?
I cannot take another issue with incorrect sizes.
Do they fit ok ? any issues to look out for ? good makes ? cheap makes ? (im broke now)

I am just thinking if motad cannot send me the correct fittings

[hampshirehog]

That collar looks like it's been mashed in the past.

[ukjules]

I think you are right. there is no way it can work after checking the diameters etc with a gauge.

iv emailed motad to see if they can supply new. hope so or im stuffed and will
need a new exhasut.

[hampshirehog]

Motad should be able to help. If not you could make up some collets yourself.

[ukjules]

I am now expert at measuring and have all the measurements i need but making a collet ?

I suppose a pipe below the internal dia of exhaust head - 36.5 so about 36.3/4

I would not know wher to start to find that and also to make the end bit that pushes on the pipe
to seal ?

Dare i ask is this difficult ?
ill be honest i dont know where to start.

motad been contactd but be nice to have this as back up

[hampshirehog]

These are what you would be trying to make:

http://www.ebay.co.uk/itm/UNIVERSAL-MOTORCYCLE-EXHAUST-COLLETS-HALF-MOON-35mm-X-26mm-/271902292989?pt=LH_DefaultDomain_3&hash=item3f4ea3bbfd

You could start by cutting your existing collars in half.

Or maybe those ones on eBay would work with a little bit of adjustment.

[ukjules]

i have just done some more calculations ..

downpipes ext dia = 31.3mm
so i need a collet to go over this.

the end lip of the downpipe is 34.2mm

head exhaust outlet internal - 36.5mm

I think what you inform of will do it !
I will try tomorrow as mine are useless as they are and i need new so i can all but try.
An excellent idea and thanks ! this is likely to work.

Absolutely brill - bike could go tomorrow ! .....

[ukjules]

@ hamp..hog

I have to say that advice was possibly the singular best advice i have had.
Forever since i had this bike (my first gs) 4 -5 years ago i have issues with the exhaust onto the head.

I did what you suggested and cut them in half this morning. ground them down a bit , tidied up edges
and they went back on so easily it was fabuloustastic.

I canot tell you how much easier this makes working on this bike and i no longer fear the downpipes
coming off.

Anyway - with that i got my top end rebuld back on track . Just been out on it
for first test ride. It sounds the best it ever has as the exhaust for once is sealed.
it is smooth.
thanks so much for that advice - it so worked and has transformed my bike.

[Weapon]

I know you have it fixed, but was wondering how it happened. It looks like it squished out like a rivet from being tightened. I wonder if the metal is too soft for the application.
Or maybe the heat made it soft causing it to squish.

[1948man]

Fabuloustastic is good!!!

[ukjules]

How it happened:
The fact is I dont know. This is my first GS and I when i took off the exhausts I
thought I had to endure the ill fitting collets. They are squashed in and deformed.
One of its past users must have forced them in , overtightended. this figures as there were
stripped threads when i got it -- 5 years ago.

When I bought another head for the bike the exhaust gap was slightly smaller and the collets simply
would not fit - unless i seriously forced them.
As this time I am doing everything right , mechanically right i had to enquire.

The bottom line is simpky cutting them in half, putting a drill on its side and clamping it
to the bench to grind them smooth afterwards and then hitting them into shape
on the floor with a hammer has made them work "perfectly".

So from deformed useless collets to perfectly sealing collets in 5 minutes.
brilltastic !

[Chris G]

It would still be worth contacting Motad, they have always been helpful when I needed info, they are often on flea bay selling off there discontinued exhaust systems. There's a full system on there now for a GS 550. 351436034655

[Weapon]

ya that fix was pure genius