Topic: Question for those who completed dual disc upgrade...

[hevykevy420]

Did you guys just leave the wheel axle slightly "loose"?  Since you can't retain the trim cover over the speedo drive plate, when you crank the axle tight, it applies pressure to the speedo drive.  This doesn't work, because the speedo drive needs to be stationary, not spinning with the axle, or speedo drive plate.  I'm looking at it and can't figure out how to get around this, other then leaving the axle nut untorqued.  I've already trimmed and flattened the speedo drive plate so that it takes up less width on the axle, according to the mod...

Any advice would be appreciated.

PS- I've read all the FAQ's on this, and unless i missed something, I don't see anything on this!!

[bryanj]

The speedo drive plate needs to fit inside the hole in the disc rotor flat onto the wheel hub boss with two "tangs" formed to fit into the recesses. Does that make sense? a picture of what you have would help

[lordmoonpie]

The speedo drive plate needs to fit inside the hole in the disc rotor flat onto the wheel hub boss with two "tangs" formed to fit into the recesses. Does that make sense? a picture of what you have would help

+1 to that - there are tangs and recesses to make it all fit snug and tight.

Didn't have this problem myself as I junked the speedo and ripped the spacer out of the drive so I could throw the rest away...although that's one of the benefits of building a race and not a street bike, I have to say that the 2 disc conversion has been a real headache and I still haven't worked out whatthe last thing I bolt on will be when it all finally gets bolted up...

[bwaller]

Here's a poor pic to show what Bryan has mentioned. One other point to keep in mind, just allow a little slack where the speedo drive tabs fit in the slots on the hub, that gives the plate a chance to center on the axle.

[hymodyne]

Looking at the picture here, I discovered that my speedo hub is wider in diameter than the one in the pic. It has two tabs, but the outer rim of the hub overlaps the rotor by about 1-2mm. The removal of the chrome retainer ring also leaves about 3mm more axle shaft than my axle nut can tighen down, leaving the whole hub free to wobble that distance on the axle. should I shim the hub with the right sized washers to account for the retainer ring's removal?

If I dremel cut the tabs about 2mm further into each side of the speedo hub, I could bend them 90 degrees and fit them into the hub boss slots like the pic below; the only difference would be that the speedo hub would be sitting on the rotor, not the hub boss.


hym 

Here's a poor pic to show what Bryan has mentioned. One other point to keep in mind, just allow a little slack where the speedo drive tabs fit in the slots on the hub, that gives the plate a chance to center on the axle.

[fuzzybutt]

not sure where it was i read this but supposedly you use a speedo drive plate from a cb500/550 to get the clearance you need

[hymodyne]

 The chrome retainer ring has two places where the tabs on the speedo hub fit.
 The link with directions for installing a twin disc require that you remove the chrome retainer ring.
 The retainer ring normally holds the tabs of the speedo hub firmly to the wheel boss and wheel hub.
 Why can't I just attach the speedo hub, chrome retainer ring and all, to the newly added brake rotor?
 The hub and retaining ring fit onto the wheel hub with both rotors in place.
 If I install the bolt heads on the speedo hub side, there are no clearance issues with the hub.
 by installing the entire hub/retaining ring to the outside of the newly added  rotor, the spacing issues mentioned in  my earlier thread are solved; the speedo hub is held against the hub/rotor, and turns with the wheel as it is bolted to wheel hub and rotors.

...or does adding the thickness of the rotor to the total width of wheel on the axle by putting the retaining ring and speedo hub on the outside make it too wide for the forks?

I found a 750 KO front wheel and speedo hub on ebay, but I don't want to buy a whole wheel for one small piece.
thoughts?

hym

[Jim F]

I just made my own spacer and will use an electronic gauge package
from this company

http://www.veypor.com/veypor.html

but in a nutshell this is what I did when I mounted RC51 rotors to a GL front end

[hymodyne]

anyone have experience with this veypor system? How does it convert to our bikes?

hym

[bwaller]

Hym,

You'll be too wide unless you modify the speedo drive. Here are a couple more pics, the first shows the original drive and the modification. The second shows a little better how the modded drive "ears" fit in the two slots of the hub.

Clear as mud?

[mrblasty]

anyone have experience with this veypor system? How does it convert to our bikes?

hym

Ive got the trail tech veypor on my bike and if I had it to do all over i would have bought the speedo only model and saved a few bucks on the conversion.  The Tach feature on mine is absolutely useless.

[Bodain]

Yea I wanted the upgrade so I sold the 75 K and got a 78 F..   <Grin>

[hymodyne]

Thanks bwaller,
now I get it. I and my dremel will be busy tomorrow...better than grading student papers though

hym

Hym,

You'll be too wide unless you modify the speedo drive. Here are a couple more pics, the first shows the original drive and the modification. The second shows a little better how the modded drive "ears" fit in the two slots of the hub.

Clear as mud?

[hymodyne]

Thanks to the first thread about this refit and the subsequent posts by Bryanj and bwaller especially, my speedo hub will now work with my twin 550 disk setup.

I dremeled off the outer tabs and portions necessary to leave only the "tangs" that bryanj described and bwaller showed in his pics.

again many thanks, and now, on to the next crisis...

hym

[bryanj]

Well done i did have a pic of the required drive in a post a long while back but didnt have the "newer" one to put in as comparison---its difficult describing, especially when we talk two different types of English!!!

[hevykevy420]

FWIW I know this is an old post, but I wanted to put up my results in case it will help others.  I realized that the '78 hub that I was using did not have the reliefs cut out of the hub on the right side for the altered speedo drive tangs to insert into.  Basically I had to dremel off a bit of the hub on each side for the altered speedo plate to fit into.  The older hub I had came with these reliefs from the factory...

So if anyone is doing this dual disk upgrade on a '77 or '78 hub there is an extra step.

[ev0lution7]

i realize that you asked about deal disk but as of late we have found that we can get MUCh better braking out of a single disk with out the extra weight or unsprung weight, or complexity of the dual disk setup by running a.....

EBC ROTOR

its a direct fit replacement for the stock and has many many benifits compared to 2 stock rotors even cross drilled ones...

IE: EBC floating modern disk materal (wont ever sqeak)
Stock... STEAL very bad for brake surface... solid mounted to hub... very heavy...