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CB750P7 front hub - are these extinct?

(4E5-W2472-00) DOUBLE SEAT ASSY Forum

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Soyboysigh

posts: 2
posted: Sunday, March 19, 2017 15:22
Subject: CB750P7 front hub - are these extinct?

Hi - I'm wondering whether there's every any hope of obtaining the CB750P7 front hub.

I'd snap up at least a couple of 'em, IF they were available. Even 2nd-hand would be acceptable.

It's not that I'm restoring this particular model, it's just that I'm doing a wire-spoke wheel swap on my "CB900K0 Bol Bomber" ('82 Bol D'Or based homage to the '65 Black Bomber, DUH) and the 5-bolt dual-disc front hub is only found on this model & vintage of CB750 Police bike.

WITH this hub, I'll be able to fit such special front discs as the vented double-thick 296mm automotive style discs from the CB1100R-c/d ('82-'83) slash CBX pro-link slash GL1100A Aspencade - OR the '81 only CB1100RB dished one-piece 296mm discs, or the CB1100F spiral-center 9-rivet 276mm discs, but with some Cast-Iron outer discs in 296mm minimum.

See, the vented discs would either need the center-carrier swapped out to the 6-bolt type, with replacement rivets (or bolts, I suppose) or the carrier be drilled & filled etc. Meanwhile the CB1100RB rotors are at least 50% lighter than the regular composite 9-rivet discs, but for the 6-bolt hub they would have to be drilled anew, & have the old bolt-holes welded & filled in. Perhaps the best of all possible options, that CB1100F style center-carrier is so much larger than the regular 9-rivet carriers, that the outer disc ring wouldn't be as wide, ergo it'd be less heavy overall in the same sizes. Now THAT'S the perfect period-correct set of discs for an RCB/RS1000 replica, or my "retro-fried" version of which for that matter.

A 296mm version of the 276mm CB1100F discs would be awesome enough - a Cast-Iron version of which, all the better. And cross-drilled of course, even better still. But if we could make 'em even BIGGER now....

Ideally, 316mm to suit the '96+ ST1100-ABS 43mm TRAC fork, the only 43mm anti-dive fork Honda put on a street-bike - I'd very much like to combine two right-hand-side legs, and whip up a mirror image caliper hanger (suitably off-set for the pivot being shifted outboard, of course) - and call it a pseudo-replica of the NS500/NSR500 front end. At which point, I'll be bugging you for those big orange "SHOWA" stickers!

And hey - if ya'll have any pull with the MORAD company? They need to start making the old Akront "NERVI" rims once again. Now that people are perfecting methods for rebuilding the COMSTAR wheels, these 50% lighter, any size you like, awesome Unobtainium rims would be THE $#*% !!!

I've found one in 2.50x18" for up front, but I'm still waiting for a 3.50x18" or 4.25x18" to match either of my two main sets of wire-spoke rims. How nice would it be to have a "Wet/Dry" set of wheels for track days? You could have the one in wire-spoke period-correct ultra-light etc, the other pair in COMSTAR style, but in an ideal rebuilt version of which with a CB400TCB400N size rear hub but replaced with a core hub cut from a more modern cast/mag wheel - in other words, a truly low mass rear disc-brake type hub, with the ultra light weight rims in sizes like I'm talking about here - I'd build MINE in the early SILVER style, with the alloy spoke blades ergo '79-vintage - a bit tricky finding that one in 18" front, but they're out there....

Of course, a pair of wheels such as THESE would solve all of my brake-rotor fitment issues! However, the wire-spoke type rims I've got on hand are the super DUPER light-weight types, such as the "SUPER-AKRONT" in 3.50x18", or Akront 4.25x18" which is not quite as light in weight nor are they as beautiful - but the greater width would allow some more modern Sport-Touring radials, a 160/60ZR18 rear - Which seems almost TOO big for the '79-'83 DOHC-4 series.

It's so very tempting right now, to just use a rear DRUM brake, a smaller more compact one than the standard CB750K item -laced into that 3.50x18" rim. It would solve practically everything on the rear end of that bike, I could run my Marzocchi shocks without an under-slung caliper, etc etc. Soooo very tempting right now!

I'll tell you what though, if I could get my hands on those "NERVI" rims, I'd probably forget about the wire-spoke thing altogether!

So yeah - BOTH would be nice, but I'd by happy as all get out if I could just have one or the other: the 5-bolt dual-disc wire-spoke front hub,. OR the wider "NERVI" rim for that rear wheel....

And a nice off-the-shelf kit for a "Front Hub Trick" style conversion, so Honda 'F-olk could make use of a more light-weight compact rear HUB - which would lace up to the more common & cheap on the ground HARLEY pattern drilled rims. A bolt-up cush plate, with or without a corresponding sprocket carrier, is all that's really needed. The disc could be easily picked up from any number of sources, but the OEM rotors would look the most period-correct etc.

And perhaps just one MORE decent off-the-shelf item, might be a rear caliper hanger to bump the OEM rear calipers inboard by a couple of centimeters, either the 276mm discs just like the twin-pot caliper from FT500 Ascot or VF750F/VF1000F etc, OR perhaps to suit the 6-rivet 4-bolt 260mm disc from the front end of CB350F/CB400F etc - Ideally, the early 'F1 & GL1000 rear calipers (the latter, flipped upside down for the under-slung version) could have the axle hole in the integrally cast caliper hanger, drilled out eccentrically then back-filled with a spacer and/or a needle-bearing. There MIGHT just be enough "meat" in the casting, to tuck the caliper in tight enough, for either the 276mm or 260mm rear disc. Maybe 240mm for the 5-bolt dished one-piece front disc off of CX500/CB250N etc, on a 5-bolt COMSTAR front hub, swapped onto the rear - Heck the 2.50x18" front Comstar wheel from GL1100A would be good-to-go, though ideally this would all be disguised "stealth" style, on a seemingly "bone stock" CB750F2, with 39mm fork & those dished 296mm discs from the CB1100RB, like I say: everything improved functionally but keeping with the original aesthetic aka "STEALTH" mods!

That way, everything's "period-correct" and looking OEM as it should, with rear-sets built from all OEM parts, shorter brake pedal etc etc - And of course the SOHC era alloy throttle housing / switch-pot could be modified to the DOHC style "Sport-Kit" orientation, with the cables jutting forward & upward, which would only require some modification to the top half of the clam-shell housing, ideally this top half could be manufactured in some reasonable quantity?

It would be nice to think, one could whip up a "stock" looking Honda, with race-bred chassis on par with any concurrent limited edition Ducati etc. It could sit there with the restored 'K0 Sand-Cast or 'F2 bikes, looking like ducks in a row - You could PAY for the whole endeavor by racing vintage Ducati and Kawasaki owners for "pink slips"....

*cough*

YES - as I was SAYING. The CB750P7 40-spoke 5-bolt dual-disc front HUB!

PLEASE?


-Sigh.

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Soyboysigh

posts: 2
posted: Sunday, March 19, 2017 15:24
Subject: Re: CB750P7 front hub - are these extinct?

Whoops! I think this is posted to the wrong forum....

I'll post the duplicate elsewhere, just in case.

-S.

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