Does anyone out there have any knowledge of how the parts for the double-disc 1977 GS750 (DB) differed from the single disc model (B)?
I have a 77 B - single disc, wire wheels, 300mm disc, Tokico caliper with a 43mm piston.
Having done a complete rebuild, I thought I may as well upgrade to the double-disc set-up. However, tracking down information on the DB has proven difficult - none of the parts fiches even list the possibility of a right-side brake, yet it is undoubtably a genuine factory model.
First step is to obtain a right-side fork leg that has the cast bosses for the caliper mount - not present on the B. There's no parts listing for one, and I've never seen any for sale - so the answer seems to be to use those from a double-disc E model.
However, because the E models use 275mm discs the bosses are placed lower on the fork leg to bring the caliper down to the disc - meaning that the 300mm discs can't be used.
A right-side caliper was hard to find until I realised that the 79 850G used the same calipers, but with a 38mm piston - they're easy to get.
Back to the question - did the DB use the same fork legs as the later E model, and also use the smaller discs; or did it have its own specific right fork leg with high bosses to allow for the larger discs?
Given that the E model (cast wheels) did not exist when the B or DB was released, it was not a question of parts sharing at that time - the parts would have been specific to that model - would Suzuki have gone to the trouble of manufacturing different discs for the same bike?
The 'simple' answer (aargh, more money!) is to get a set of 275mm discs, but I am still curious.
(I initially fitted one of Salty Monk's excellent twin-pot conversions, but I found that the regulations here in New Zealand are that such modifications must be certified before registering the vehicle - involving transporting it 100 kilometres, leaving it for a day, and $500!)
I have a 77 B - single disc, wire wheels, 300mm disc, Tokico caliper with a 43mm piston.
Having done a complete rebuild, I thought I may as well upgrade to the double-disc set-up. However, tracking down information on the DB has proven difficult - none of the parts fiches even list the possibility of a right-side brake, yet it is undoubtably a genuine factory model.
First step is to obtain a right-side fork leg that has the cast bosses for the caliper mount - not present on the B. There's no parts listing for one, and I've never seen any for sale - so the answer seems to be to use those from a double-disc E model.
However, because the E models use 275mm discs the bosses are placed lower on the fork leg to bring the caliper down to the disc - meaning that the 300mm discs can't be used.
A right-side caliper was hard to find until I realised that the 79 850G used the same calipers, but with a 38mm piston - they're easy to get.
Back to the question - did the DB use the same fork legs as the later E model, and also use the smaller discs; or did it have its own specific right fork leg with high bosses to allow for the larger discs?
Given that the E model (cast wheels) did not exist when the B or DB was released, it was not a question of parts sharing at that time - the parts would have been specific to that model - would Suzuki have gone to the trouble of manufacturing different discs for the same bike?
The 'simple' answer (aargh, more money!) is to get a set of 275mm discs, but I am still curious.
(I initially fitted one of Salty Monk's excellent twin-pot conversions, but I found that the regulations here in New Zealand are that such modifications must be certified before registering the vehicle - involving transporting it 100 kilometres, leaving it for a day, and $500!)
