GT550 twin disc upgrade....again!

[pfg49]

From looking at this and other forums I can:-

1- Get a left fork leg, a left hand mounting bracket, a GT750/GS750/1000 master cylinder, another GT550 caliper, use standard discs, route brake lines as necessary.

2- As above, but using another type of disc. Is there a better type?

3- As 1 but using GS 750/850/1000 calipers but from which years?

4- Do something incredibly complicated that costs loads of money and takes 2 years to do!

Simplicity appeals to me, and 1 is the simplest and the cheapest, and I would only have to buy the master cylinder. But I feel that the disc is the weak link here, and I can't seem to find any reference to a better disc. Any help with this would be appreciated

[canaletto5]

Not totally straightforward. The left side caliper has a handed floating brake pad carrier, you can't just mount a right side caliper on the left side. Kev

[Alan H]

What model 550 do you have? If it's 'late' you might not need a fork leg (or fork bottom).
Even better, if it's a J with the 4 leading shoe brake, that's better than a disc setup anyway!

[pfg49]

Not totally straightforward. The left side caliper has a handed floating brake pad carrier, you can't just mount a right side caliper on the left side.

Kev,
Surely it's only the mounting bracket that's different?

Alan,
It's a 1976 A Model.

If you look close enough at the picture you can see the fork legs are marked L and R.

[canaletto5]

Hi

If by mounting bracket you mean the moving part that runs on the mounting bolts and carries one of the disc pads then yes, that is the part that is different from the right side

Kev

[canaletto5]

Part number 2 in the diagram

https://www.robinsonsfoundry.co.uk/shop ... ontcaliper

[Alan H]

We might be able to advise you better if we knew who you are, which bit of the world you reside in and how technical you are.
It's pointless anyone giving you lots of details if you don't understand, for instance.

[pfg49]

OK Alan,
I'm Peter, ex-Deep Sea Chief Engineer combined Steam and Motor. Last deep sea ship powered by a Sulzer 8RND90 turbo charged 2 stroke, 8 cylinders, 900mm bore, 1530mm stroke, 7,788,000 cc or 7,788 litres, about 27,000 bhp @ 99rpm, maximum revs 115 RPM. Ex-various companies in the 1970s North Sea oil industry, oil rigs, supply boats and tugs responsible for all on-board mechanicals. Senior engineer Jeddah International Airport all mechanical systems. 1984 to 2007 Raced (I won the Jaguar Car Club Saloon Car Championship 1996) and then professionally helped prepare classic saloons and sports cars, Mustangs, Camaros, Sunbeam Tiger, E-Types, XK, Jaguar Mk2 saloons, Escorts etc. Currently part owner of Barons Classic Car Auctions, (next sale 22 September Sandown Park Esher, get your money out, I need money for my bikes!) Owned motor bikes since I was sixteen and currently have,
1 off 1974 Triumph Trident
1 off 1976 Laverda 3C 1000
1 off 1971 BSA A65 Lightning
2 off 1980s Yamaha SRX600s. These are for sale cheap if any one is interested.
1 off 1976 Suzuki GT550
1 off 1976 Suzuki GT550 parts bike
1 off 1966 Beezuki, which is a BSA A65 with a slightly tuned GT550 engine i'm building using bits from the above parts bike.

So, I'm alright with most things, weak on electrics and complicated machine work, but as my business partner is an ex-Ford toolmaker i've got backup on the machine work! I don't know everything, and frequently make mistakes. I'm asking people on here things because I need the benefit of their expertise to find out about thing I don't know and I need to learn about. I won't post my opinion on subjects I know nothing about.

Does that help?

[Alan H]

Very nice intro! Welcome to the madhouse, Peter. Nice to have another Engineer on board - I'll try to be gentle with electrical help too.
If you have a look at my 550 restos;
K - Clicky
A (very non standard!) - Clicky
J (current resto) - Clicky
There might be something that might answer some questions.

[Alan H]

You'll also need a 'D' marked master cylinder for twin discs, like this - ebay item 123975403437.