help with '76 CB750F Frankenbike

[TOOLS1]

There is plenty of room to mount the sprocket "backwards". But who decided that putting the sprocket on with the offset going to the inside was "backwards"? I myself would rather use the rear sprocket "backwards" and not have to worry about chain/sprocket clearance at the engine.
TOOLS

[riffman12]

hm good point.

Now to see if they can make it in a 5 bolt

[TOOLS1]

riffman12 wrote

hm good point.

Now to see if they can make it in a 5 bolt

  That is one oddball cush drive.
TOOLS

[shinyribs]

Each spoke of the cush houses a stud for a respective sprocket bolt hole.

C'mon maaaaaan....keep up!!

[riffman12]

so tonight I got the rear wheel bearings in, fixed my swingarm bushings, and mock-mounted the rear wheel.

The shocks seem alriiiight at this point (I'll take pictures when it's light out)

but I've definitely got a major chain line issue. The rear sprocket sits out a lot further than the front. I'm not even sure if a 10mm offset sprocket will be enough. I'll post a pic when I can find something long and straight enough to measure it properly.

[shinyribs]

Where are you located at, if you don't mind me asking? If you've got a good usable sprocket, and can get some accurate measurements, I can shave down your cush in the lathe to align your chain (provided there is enough material left behind). Or Tools could do it, too, if he's closer...and willing.  Not trying to create work for ya, Tools.

You can reply with a PM (private message) by clicking on anyone's username here. It will send the message to that person email they used to register.

[riffman12]

That would be awesome if you think it can be done! I'm located in the San Francisco bay area. East bay specifically.

Which part would you remove material from? I would have thought youd have to modify the spacer between the cush and the huv. And how do you account for the loss of total axle spacing? Just an extra spacer?

[TOOLS1]

You would remove material from the cush drive where the sprocket mounts, providing there is enough material there. The wheel spacing would not be affected. The hardest part about doing the procedure, would be removing the studs.
TOOLS

[riffman12]

ohh I see.

Would it not be possible to thin down the spacer that sits between the wheel and the cush? Part #9 here:

http://cdn.partzilla.com/diagram/honda/14445Z/ILLUST/F1444/5Z13.png

Effectively pushing the cush further into the hub. Then just add a small spacer outside the cush?

[shinyribs]

That would be a much harder way to do it. Taking the excess off of the inside of the cush will require total respacing of the axle and all adapters from that side out. You will also end up having to shave down the cush rubbers and will end up with a cush that looks ''sunk in''. You would likely also have to trim the inner cush studs and possibly clearance some other areas. I imagine a snowball effect happening if you start trimming the inner side of things.

Like Tools said, once the studs are out of the way, you can just shave the sprocket mounting surface down and call it a day. I've removed cush studs using heat before. It wasn't a super easy job, but definitely not bad with a little heat, patience and carefulness. Doublenuts, heat the threadlocker to release and they should thread out just fine.

[riffman12]

I've tried emailing both of you, but my email says it is undeliverable each time.

Next issue: is my '77 swingarm longer than the '76 one? I ask this because I ordered my hagon shocks for a '76F rather than a '77F. Any problem with this?

[riffman12]

so I just found this while poking around...



I wonder what the chance are of that CB450 carrier fitting my '79 Comstar...


Edit: $20 shipped from ebay. Should be here in 2-3 days. Wish me luck!

[shinyribs]

riffman12 wrote

I've tried emailing both of you, but my email says it is undeliverable each time.

I blame ISIS.

Nice find on the 450 stuff. Let us know how it pans out.

[riffman12]

well the sprocket carrier arrived today annnnnd it doesn't fit

The way I see it I have 2 paths forward:

1) keep trying to make this mix of parts work. Either mill down the sprocket carrier I have or hope an offset front sprocket fixes my issue. My worry wth this is that the bike will continue to fight me all the way. This is my first motorcycle build and I'm worried than I'm over my head with all this custom stuff.

2) Revert back to all 1976 parts (swingarmm wheel etc.) and possibly a GL1000 front end. I don't have any of the '76 parts so I'd need to do some eBayiing. I'd be throwing away a lot of time and money I've already invested into the '77 and '79 parts, but it would make things a lot easier going forward.


Pretty bummed at the moment as I was really hoping that new sprocket carrier would help me out.


Would anyone like to convince me whether or not a GL1000 front end swap is a good idea?

[TOOLS1]

Yes, A gold wing front end swap will definitely cure all your rear wheel problems. You still might have a third option, get a 77-78 "CB 750 F" rear wheel. And then you should be able to use the early cush drive.
TOOLS

[riffman12]

ha sorry I skipped a step in my thought process there.

- sick of funky wider swingarm problems

- would be nice to just have a '76 swingarm

- front wheel is a comstar

- I don't think there is a comstar that fits the '76 swingarm

- would need spokes in the back, spokes in the front to match


but that's a good point. Forgot the older comstars can accept the older cush drive. Would that combination fit in a narrower '76 swingarm?

[TOOLS1]

Yes, you would just need to use the early wheel spacers, cut yours down, or make new ones. Here is a 77-78 "F" rear wheel on e bay. http://www.ebay.com/itm/Rear-Wheel-Sprocket-Tire-1977-1978-Honda-CB750-cb750F-Metzler-120-90-x-18-/251288175539?hash=item3a81f143b3:m:m4xBbZuXSZ8z_LOQtV2uJ1A&vxp=mtr

Here is another one with the disc http://www.ebay.com/itm/1978-Honda-CB750f-Super-Sport-OEM-Comstar-Rear-Wheel-89-/131661939023?hash=item1ea7a9c14f:g:qjIAAOSw9r1WCFtd&vxp=mtr
TOOLS

[riffman12]

OK I'm sure you're getting really sick of me, but just for clarification:

if I get a 750F comstar from 77/78, I can get a sprocket carrier from any 4 lug 750 from 70-76.

Then if I get the axle spacers from a '76F... it shouuuld all fit and line up the same as the factory spoke wheel from the '76F?

How would it work with the rear brake? I assume I'd need the F2 rotor, caliper, and caliper carrier? Would that work with the caliper pivot arm and swingarm?

Thanks again man. I appreciate this big time.

[TOOLS1]

Since I have not had any experience with the CBX wheel and brake parts, I do not know if they will work with the 77-78 "F" wheel. However they might work. You would just have to try them. I would try to get a wheel with a brake disc on it though. That way you know that will work. Calipers, and caliper mounts are a lot easier to make/modify to work.
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[riffman12]

yes I figured I would get the brake rotor as well with the '77 wheel. My concern was more if the newer brake parts would work with the '76 swingarm

now Shinyribs mentioned he had a powdercoated '76F arm he wanted to sell... I couldn't get hold of him through the email system for some reason, but I would like that if it's still available.

shiny if you're reading this, can you email me at riffman12 at yahoo?