34mm Fork: Upper Triple Clamp Question

[patentgeek]

I have a set of NOS Red Wing 34mm forks that I want to install on my 1970 XS1 project to replace the original rusty fork. For the Red Wing forks to work I need a top triple clamp that actually clamps the tubes, as opposed to the current top triple clamp where the tubes are just fitted into the top triple clamp bores.

My question is whether there is a 175mm center-to-center width top triple clamp that actually clamps the tubes? If not, I will have to go with a set of 1973 triple-clamps; or 1973-76 triple clamps swapping in a 1973 or earlier stem; or find an aftermarket (e.g., Cognito Moto) top triple-clamp that will work. The 1973 and later triple clamps are wider (184mm center-to-center) but I think the offset is the same as the earlier triple clamps.

Reference link:
http://www.xs650.com/threads/will-1975-34mm-forks-fit-my-72.43850/

 

[TwoManyXS1Bs]

Have a look at Figure8's post:

http://www.xs650.com/threads/billet-triple-clamp.10214/page-5#post-459369

 

[patentgeek]

Thanks. I'm already aware of aftermarket triple clamp alternatives. My question is whether there is a 175mm center-to-center width top triple clamp that actually clamps the tubes?

 

[TwoManyXS1Bs]

Had to dig deep to find this:

http://www.bullitcustomcycles.com/products/billet-upper-triples/yamaha-xs650-34mm-fork-billet-triple

 

[mrtwowheel]

Had to dig deep to find this:

http://www.bullitcustomcycles.com/products/billet-upper-triples/yamaha-xs650-34mm-fork-billet-triple

Those look real nice, but, where do you mount your bars?

Scott

 

[TwoManyXS1Bs]

....?....bars?

 

[mrtwowheel]

....?....bars?

View attachment 113112

Oh, I get it, zip ties and a piece of pipe then.

Scott

 

[gggGary]

Had to dig deep to find this:

http://www.bullitcustomcycles.com/products/billet-upper-triples/yamaha-xs650-34mm-fork-billet-triple

Be aware of the gotchas, that guy doesn't list the three different variants needed to fit all years of 34mm XS650 triples. See recent thread about that.

 

[patentgeek]

that guy doesn't list the three different variants needed to fit all years of 34mm XS650 triples.

Is this what you are referring to?

*narrow 34mm for drum brake bikes
*wider 34mm for early disk brake bikes
*wider 34mm with longer stem starting in 1974

 

[patentgeek]

I mocked up the RedWing fork tubes on my 1970 XS1. Using the stock lower triple clamp with an aftermarket top triple clamp seems to be the easiest way to go. 1973 triple clamps are a little wider and would put the brake plate farther away from the fork leg absent dishing the front wheel to the right.

I mocked up the RedWing triple clamps, which seem to have the same offset as the stock triple clamps, but are slightly narrower so clearance between the fork legs and brake plate and hub is really tight. So tight I would be concerned about interference problems.

So I'm back to the question in my original post, looking for a top triple clamp compatible with the original lower triple where the top triple clamp pinches/clamps the fork tubes. The Cognito Moto top triple clamp is the only option I've found so far, but I'd prefer a conventional tube clamp design over their hidden pinch bolt:

https://cognitomoto.com/products/billet-top-triple-clamp-xs650?variant=32002297869

I do like the optional Cognito Moto riser mounts (although they are a little on the pricey side) as I'll be running conventional tracker style handlebars.

References to other manufacturers in the archives have resulted in NLA dead ends, so I'd appreciate any pointers to other alternatives.

 

[gggGary]

Well not quite but we didn't do a year by year listing so I'll try
rounding to nearest mm
fork tubes center to center
1970-1972 175mm
1973 on 185mm

offset fork tube center to steering stem center
1970 -1973 60mm
1974 on 47mm

fork tube diameter
1970 to 1976 34mm
1977 on 35mm

stem length grew about 1/2" in 74 also. not 100% on the year this changed.
Add to this the changes in instrument and ignition lock mounts, probably not your worry but the short version is there were a LOT of different top triples and at least 4 different lower triples used.

 

[arcticXS]

As the RD350, as well as the RD400 had 34 mm forks (Except the RD400 Daytona, that had 35 mm), it is likely that those top triples would fit at least some of the XS 650 versions. They even shared the brake caliper and disc layout.

 

[gggGary]

As the RD350, as well as the RD400 had 34 mm forks (Except the RD400 Daytona, that had 35 mm), it is likely that those top triples would fit at least some of the XS 650 versions. They even shared the brake caliper and disc layout.

Maybe but many of those front wheels had narrow hubs compared to the 650's, a few guys here found that difference after a lot of head scratching.

 

[arcticXS]

Maybe but many of those front wheels had narrow hubs compared to the 650's, a few guys here found that difference after a lot of head scratching.

I am believe even the single disc XS650 hub is similar to the RD 350 hub. The disc offset is exactly the same, even when the XS disc is 298 mm and the RD267 mm. At least it would be easy to check out if the RD has the same C-C and offset as one of the XS versions. I do know that the drum brake YR5 350 and DS7 250 has narrower forks than the disc brake RDs, maybe that's what you mean?

 

[gggGary]

All I can tell you is that I have had Yamaha dual disk flange, front spoke wheels with a narrower rotor to rotor and overall width than the XS650 wheels. Not sure what model they were from.

 

[patentgeek]

As the RD350, as well as the RD400 had 34 mm forks (Except the RD400 Daytona, that had 35 mm), it is likely that those top triples would fit at least some of the XS 650 versions. They even shared the brake caliper and disc layout.

Thanks for the RD suggestion, but I'm looking for more of a plug-and-play solution that doesn't require hours of compatibility research. Time is money!

 

[gggGary]

Thanks for the RD suggestion, but I'm looking for more of a plug-and-play solution that doesn't require hours of compatibility research. Time is money!

Where do we send the bill for work done so far?

 

[Jim]

Where do we send the bill for work done so far?

 

[TwoManyXS1Bs]

I thought time is monkeys...?

 

[Bds]

I mocked up the RedWing fork tubes on my 1970 XS1. Using the stock lower triple clamp with an aftermarket top triple clamp seems to be the easiest way to go. 1973 triple clamps are a little wider and would put the brake plate farther away from the fork leg absent dishing the front wheel to the right.

I mocked up the RedWing triple clamps, which seem to have the same offset as the stock triple clamps, but are slightly narrower so clearance between the fork legs and brake plate and hub is really tight. So tight I would be concerned about interference problems.

So I'm back to the question in my original post, looking for a top triple clamp compatible with the original lower triple where the top triple clamp pinches/clamps the fork tubes. The Cognito Moto top triple clamp is the only option I've found so far, but I'd prefer a conventional tube clamp design over their hidden pinch bolt:

https://cognitomoto.com/products/billet-top-triple-clamp-xs650?variant=32002297869

I do like the optional Cognito Moto riser mounts (although they are a little on the pricey side) as I'll be running conventional tracker style handlebars.

References to other manufacturers in the archives have resulted in NLA dead ends, so I'd appreciate any pointers to other alternatives.

I know this is an old post, but do you happen to still have the triple trees for the redwing forks? If so are you interested in selling them?