SF1 1973 exhaust flange, collar 40mm

ianpm77

ianpm77

Senior member
Hi
A long time since I last posted anything sorry. Sepsis recovery (January) for me and the restoration has been very slow.
Exhaust flange/collar needed, UK. Wanted.
SF1 1973 750 . 40mm exhaust headers etc.
Original one is cracked and bent.
Before I remove the exhaust system thought I would ask if there is any chance someone in the UK has one lying around needing a new home.
I'm sure they might all be bent or cracked!!!
Thanks for looking.
 
ianpm77 said:
Hi
A long time since I last posted anything sorry. Sepsis recovery (January) for me and the restoration has been very slow.
Exhaust flange/collar needed, UK. Wanted.
SF1 1973 750 . 40mm exhaust headers etc.
Original one is cracked and bent.
Before I remove the exhaust system thought I would ask if there is any chance someone in the UK has one lying around needing a new home.
I'm sure they might all be bent or cracked!!!
Thanks for looking.
Click to expand...

😳 Sepsis, luckily you’re still with us.
 
It's now possible to 3D print aluminum - last time I looked the cost was $$$ but for anyone needing an original part it may be worth. I found a place that will quote but I haven't gone any further.If someone has the CAD it would be straitforward to investigate.
 
Tippie said:
Billet ones are/were available apparently, I think Red had them made.
Click to expand...
we machine billet exhaust roses but need dimensions of your broken one as there are a few different versions especially for the 750 exhausts
have them in stock, Queensland, Australia

Motalia in UK also machine billet roses I believe, not 100% certain on that as I have no need to look at their website
 
Hi
I've not taken the exhaust system off yet.
The only reference I have at the moment is 40mm Dia Down pipes and it being 1973 SF1.
Not sure if it is the type that use half ring spacers?
Thanks for your reply.
I know now that I can get new billet ones, but with the bikes rare patina. I think new ones would " stick out like a sore thumb".
Just after an original straight non cracked one.
I'm waiting for one of my "good days" before I venture to start laying on the floor under a bike etc.😉
 
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ianpm77 said:
Hi
I've not taken the exhaust system off yet.
The only reference I have at the moment is 40mm Dia Down pipes and it being 1973 SF1.
Not sure if it is the type that use half ring spacers?
Thanks for your reply.
I know now that I can get new billet ones, but with the bikes rare patina. I think new ones would " stick out like a sore thumb".
Just after an original straight non cracked one.
I'm waiting for one of my "good days" before I venture to start laying on the floor under a bike etc.😉
Click to expand...
It sounds like you're a prime candidate for a hydraulic bike lift. I've had one since I realised that a combination of an accident induced back problem and the onset of knackered knees was going to be a severe restriction on working on my own bikes, in my mid-forties. I've never looked back since buying one.
 
I can virtually guarantee that SF1/2/C all use the same flange - 40mm centre hole (or to fit 40mm OD headers), 8mm stud holes, no half rings. Pretty sure that from 1973 onwards they are the same casting for all twins and triples and the differences are in the centre hole (size and/or stepped for half moons), 7mm stud holes for triples and early small valve twin heads, 8mm stud holes for SF1/2/3/C.

I have just prepped triple flanges for use on an SF-type header, drilled the holes out to 8mm and made up half rings. I needed to fit the flanges from the head end as I have O2 sensors on the headers.
 
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Thanks for your post above.
So your saying a 1000 triple " flat rear face" flange...a 8.5mm drill and maybe a round file. Will do the job on a 1973 SF1 exhaust??
Interesting as this might make my search easier and less specific.
I wish my workshop was bigger and not have a side entrance door so I could have a hydraulic lift. Another thing to add to my wishlist 😁
 
ianpm77 said:
Thanks for your post above.
So your saying a 1000 triple " flat rear face" flange...a 8.5mm drill and maybe a round file. Will do the job on a 1973 SF1 exhaust??
Interesting as this might make my search easier and less specific.
I wish my workshop was bigger and not have a side entrance door so I could have a hydraulic lift. Another thing to add to my wishlist 😁
Click to expand...
I can't guarantee that the 'flat face' triple flange will have the same 40mm dia - I only know that I was able to use a triple flange made for half-rings. Machining out the centre hole if there is a diff is easy peasy if you have access to a lathe, but obviously nowhere near as easy as running an 8.5mm drill bit through the flange holes.

To machine the flange you'd need to make up a boss to centre and bolt the flange to, and the boss would be mounted in the lathe chuck.
 
the twin and triple are identical, only difference comes down to the ID and bolt hole size
we do a CNC run of 36 billet exhaust roses for stock, all for a triple
then if someone orders for a 750 or a big bore triple exhaust I modify the roses to suit from the stock item
 
Hi
I've just lowered the exhaust collars from the heads 8mm studs.
The ones fitted to the bike have no grooves for any half rings, flat rear face.
No half rings.
40mm inside diameter and 8mm stud holes.
So this is the spec that I'm wanting.
Triple flat rear face collars should fit.
 
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