SFC 750 swingarm suitable for conversion for triple fitment.

Three different swingarms were used on SFCs, but if you want one for disc brake then there’s only one though.
I do have a spare one by the way, which is new and without bearings, and another which is a modified SF item but with shock mounting behind the rear wheel spindle. That one does have those forsaken rubber bushes.

Marnix
 
Thanks for replying ..yes I am using disc brake on rear .I am also using GSXR 1100 wheels . Red has supplied me with the neccessary parts to fit to a standard 3Cl swingarm and I have a modern brembo caliper. I still need to decide if I am going to attach it top as per original or bottom mountvwhich Red recommends
I also have a new swingarm axel and bearings ready to fit.
Did you have a price in mind for your new one.?
My other option I was considering was to graft the ends off my stock 3cl onto the gt750 unit that I bought not knowing that it wad shorter. But now I am wondering if it would work with a disc even aftet correcting the length to that of the original.
And where are you located..Europe?
Regards
 
Brake caliper on top will push the bracket rod, bottom will pull, which is the better configuration
 
You don't have to have an SFC version - as Tom, mentioned fitting my SF1/2 swingarm to his Jota with an underslung caliper was not at all difficult. From memory he fixed the torque arm to the original mounting point for drum brake torque arms. Tom? Pics?

Does the GSX-R have a 20mm axle? If you are really stuck, I have an SF1/2 swingarm that is slightly misaligned (came off my bike after a housemates crappy Holden panel van rolled into it 'gently'. It has been modified to take a 20mm axle. I would guess it's an easy job for a frame person to jig and straighten, which is what i intend to do with it.

I'm sure you can source one that doesn't require attention but if you are genuinely stuck I'd be happy to sell it to you for a fair price.
 
Do-able
 

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I have no idea what the best position is. I just finished restoring the ex Larry Strung 1974 SFC which had the caliper as per photo. I never touch the rear brake on the racetrack, so any position is fine with me. 😉

Marnix
 

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Although it may be more than adequate (especially as you don't use it), that set up is the worst of all options, Marnix.

Anchors such as this should be stressed in tension. When put under pressure, the cross-section should be large enough to prevent bending, making the things quite ungainly. See early GS750/1000 Suzuki models, these used a tube of about 25mm diametre with a similar geometry to your SFC.

The hole pattern in the disc is also far from ideal from an engineering POV. The holes should overlap slightly along their path through the caliper, yours are all in line. This will eventually create ridges and valleys in the disc. Not important now, as you'll probably never be able to wear it out, but not understandable why it wasn't done correctly in the first place...

Back to the original topic.

A RGS swingarm allows the fitment of a 160 tyre on a 3.50" rim, or a 150 on a 4.00", with space to spare if a #520 chain is fitted. Slightly more hassle than a 750 swinger, but offers the advantage of a slightly longer wheelbase for straightline stability.

piet
 

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The rear disc comes from my other 1974 SFC which was prepared by Fausto Basaglia in Mantova, Italy, who prepared several SFCs, all in the same way. He not only drilled the discs, but removed a lot of steel, thereby making the disc considerably lighter.

Thought it would make a good combination with the rest of this lightweight bike, in SFC terms that is.. Construction wise apparently a great combination too! 😄

There was a lump of a Suzuki hub in the rear wheel, which I replaced with an original one. Many kilos (unsprung) weight gain, that’s for sure.

Marrnix
 

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We've already discussed where Larry's original rear hub and disc went, eh Marnix!! And the guy I swapped it to for the SF3 clutch and gearbox still has them - and doesn't want to part with any of it. I rang him recently on behalf of someone on here looking for an SFC disc for an endurance racer rep. He seemed to think the hub would be devalued if he couldn't supply a disc with it - which I told him I disagreed with totally. SFC hub is and SFC hub - tooth of a hen.
 
piranha-bro2 said:
You don't have to have an SFC version - as Tom, mentioned fitting my SF1/2 swingarm to his Jota with an underslung caliper was not at all difficult. From memory he fixed the torque arm to the original mounting point for drum brake torque arms. Tom? Pics?

Does the GSX-R have a 20mm axle? If you are really stuck, I have an SF1/2 swingarm that is slightly misaligned (came off my bike after a housemates crappy Holden panel van rolled into it 'gently'. It has been modified to take a 20mm axle. I would guess it's an easy job for a frame person to jig and straighten, which is what i intend to do with it.

I'm sure you can source one that doesn't require attention but if you are genuinely stuck I'd be happy to sell it to you for a fair price.
Click to expand...
Thanks for the offer..but I have all the parts and adapters from Red , originally for the Stock 3cl swing arm all made for the 1100 wheels using the Stock axle if I remember correctly. with underslung caliper. Still have to sort out the torque arm . So anticipating it would transfer across without too much trouble.

And now the RGS option enters the scene. What's the increase in wheel base over the 3cl? Not that I have to worry about high-speed stability over here.
Head spinning increasing rapidly..
 
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I have a spare RGS swing arm, but heavens know how much it would cost to ship from IOM to Cayman. Perhaps some tax dodger moving between our islands could volunteer to carry it in their luggage.....
 
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