Author Topic: 1976 CB750F - first bike, first build - mild cafe (Read 36490 times)

riffman12 · « **Reply #50 on:** November 20, 2015, 01:56:19 PM »

changing the front sprocket carrier would really be just so I don't need to have an offset front sprocket.

madmtnmotors · « **Reply #51 on:** November 20, 2015, 02:01:35 PM »

Quote from: riffman12 on November 20, 2015, 01:56:19 PM

changing the front sprocket carrier would really be just so I don't need to have an offset front sprocket.

Front sprocket carrier? You mean the output shaft?

riffman12 · « **Reply #52 on:** November 20, 2015, 02:24:02 PM »

Quote from: madmtnmotors on November 20, 2015, 02:01:35 PM

Front sprocket carrier? You mean the output shaft?

no, this:

is that not what it's called?

Jerry Rxman Griffin aka MuthaF'er · « **Reply #53 on:** November 20, 2015, 03:26:57 PM »

Rear sprocket is carried on that.

Front sprocket fits on the output shaft.

riffman12 · « **Reply #54 on:** December 03, 2015, 09:26:44 AM »

so I'm trying a slightly different solution to fix my chain line...

my wheel has a 5 stud rear sprocket so I can't use an earlier 4 stud sprocket carrier.

BUT I found that the '82 - '86 CB450SC uses a skinnier 5 stud carrier. Pic of it on the left:

Ordered one off ebay...wish me luck

calj737 · « **Reply #55 on:** December 03, 2015, 09:54:32 AM »

did your measurement account for the thickness of the sprocket on the 600?

Jerry Rxman Griffin aka MuthaF'er · « **Reply #56 on:** December 03, 2015, 10:41:59 AM »

post up your CBX sprocket carrier that came with your CBX wheel.

riffman12 · « **Reply #57 on:** December 03, 2015, 10:43:28 AM »

Quote from: calj737 on December 03, 2015, 09:54:32 AM

did your measurement account for the thickness of the sprocket on the 600?

sorry not quite sure what you mean. I'm not using the 600 carrier, I think that's just in the pic for comparison

I'm using the CB450SC carrier. I don't even know if it will fit on my hub to be honest - just that it's one of the few I've seen with 5 studs that's skinnier. I'm winging it a bit here.

If this doesn't work, I'll either be machining down the surface on my current carrier, buying an offset front sprocket, or getting a new wheel (and possibly swingarm) all together

riffman12 · « **Reply #58 on:** December 03, 2015, 10:45:35 AM »

Quote from: Jerry Rxman Griffin aka MuthaF'er on December 03, 2015, 10:41:59 AM

post up your CBX sprocket carrier that came with your CBX wheel.

Not at home at the moment, but here's a couple pics of it. You can see how thick it is in the 2nd picture.

riffman12 · « **Reply #59 on:** December 06, 2015, 07:39:18 PM »

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?

timbo750 · « **Reply #60 on:** December 06, 2015, 09:00:58 PM »

Make a decision on what it is you want the bike to be when you finish. Then persevere with it and be patient, the answers will come to you. However if you just want something to ride then do what is the easiest. I am into my 4th year, I was in no rush, the bike was a basket case and I wanted to get it right the first time. The next builds will only get easier.

Sent from my GT-I9505 using Tapatalk

Jerry Rxman Griffin aka MuthaF'er · « **Reply #61 on:** December 06, 2015, 10:35:59 PM »

Forget the front for now and concentrate on the rear. Fix one thing at a time ;-)

Keep in mind you use EBay so unload your unused stuff there and it won't hurt so bad.

Persistence and patience are virtues.

Retro Rocket · « **Reply #62 on:** December 07, 2015, 03:34:35 AM »

You need an early F model swingarm first off, get that sorted then attack the rear wheel, Jerry went through the F2/3 swingarm problem a few weeks back, its better than trying to change the top shock mounts... By "hoping" parts fit you are going to end up with more problems, your CBX rear wheel shares its chain line with the Boldor, since we haven't established the difference in chain line between the CBX/Boldor and the early F model, everything is a guess, some very accurate measurements need to be taken before going any further....

riffman12 · « **Reply #63 on:** December 07, 2015, 08:27:34 AM »

OK well to avoid redoing the WHOLE front and rear end with spokes... this is my current plan:

1) find a '75/'76F swingarm - anyone have one they want to sell?

2) Find a rear comstar from an F2 bike (77/78) with the 4 stud cush drive

3) get a narrower cush drive from any pre-77 bike, mount it to the F2 comstar

This way I should have the correct width swingarm and a rear comstar with the same spacing and chain line as the factory '76F spoke wheel...right? Or am I missing something?

Jerry Rxman Griffin aka MuthaF'er · « **Reply #64 on:** December 07, 2015, 09:29:42 AM »

Swing arm - no problem. Axle, brake stay, adjusters included. $28 OR BEST OFFER. Maybe $28 and free shipping? Blast and paint or let the coater do it for you.

http://www.ebay.com/itm/1976-Honda-CB750-CB750F-CB-750-f-swingarm-swing-arm-/301275380362?hash=item4625697a8a:g:~4AAAOSwEK9T6TCp&vxp=mtr

Wish I could help you with my spares but until both bikes are done and tested I won't start unloading.

riffman12 · « **Reply #65 on:** December 07, 2015, 11:39:43 AM »

Thanks again, Jerry. I'm in talks with a guy who has a '76 arm thats already PC'd black. If that doesn't work i will head to eBay

Do you think this plan of older cush drive on 77/78 Comstar will work? Are the spoke and comstar cush drive's interchangeable? I've been searching a lot and can't find anyone that's done it, only spoke to spoke cush conversions ('75K cush on a '77K for example)

Retro Rocket · « **Reply #66 on:** December 07, 2015, 04:08:51 PM »

Quote from: riffman12 on December 07, 2015, 11:39:43 AM

Thanks again, Jerry. I'm in talks with a guy who has a '76 arm thats already PC'd black. If that doesn't work i will head to eBay

Do you think this plan of older cush drive on 77/78 Comstar will work? Are the spoke and comstar cush drive's interchangeable? I've been searching a lot and can't find anyone that's done it, only spoke to spoke cush conversions ('75K cush on a '77K for example)

77/78 comstar cush drive is still 10mm too wide, I'd be machining 10mm off the carrier you have if you are determined to keep the CBX/Boldor wheels, you are still going to have to make up axle spacers to make it all fit.

riffman12 · « **Reply #67 on:** December 07, 2015, 04:17:50 PM »

Quote from: Retro Rocket on December 07, 2015, 04:08:51 PM

77/78 comstar cush drive is still 10mm too wide, I'd be machining 10mm off the carrier you have if you are determined to keep the CBX/Boldor wheels, you are still going to have to make up axle spacers to make it all fit.

Yes the plan is a 77/78 Comstar with a '76 or earlier cush drive.

'79 CBX rear wheel is going bye bye.

Retro Rocket · « **Reply #68 on:** December 07, 2015, 04:26:54 PM »

Quote from: riffman12 on December 07, 2015, 04:17:50 PM

Quote from: Retro Rocket on December 07, 2015, 04:08:51 PM
77/78 comstar cush drive is still 10mm too wide, I'd be machining 10mm off the carrier you have if you are determined to keep the CBX/Boldor wheels, you are still going to have to make up axle spacers to make it all fit.

Yes the plan is a 77/78 Comstar with a '76 or earlier cush drive.

'79 CBX rear wheel is going bye bye.

There should be someone here that can give you the info on the later 77/78 comstars cush drive, they have a different rear disc bolt pattern and I'm not sure about the cush drive, its possibly different too, I'd ask before buying one though just in case the early cush drive is different, you'll still probably have problems with spacers, nothing is straight forward with these conversions...

seanbarney41 · « **Reply #69 on:** December 07, 2015, 04:56:02 PM »

I was curious about this very question while recently putting new chain on my F3...but did not really investigate very scientifically. I can tell you that the exterior of a F3 comstar's sprocket carrier looks identical to exterior of K7/8 sprocket carrier, at least to casual observation. I did not pull any carriers out of the hub to compare. We do know that an early sprocket carrier will fit a K7/8 hub and vice versa and that early hub and K7/8 hub are essentially the same, only the sprocket carrier is wider on K7/8.
I would check to see if F2/3 and K7/8 have the same part number for cush drive rubbers. If yes, I think you are golden, if no it is not necessarily conclusive given all of Honda's part number funny business.

riffman12 · « **Reply #70 on:** December 08, 2015, 09:42:34 AM »

Quote from: seanbarney41 on December 07, 2015, 04:56:02 PM

I was curious about this very question while recently putting new chain on my F3...but did not really investigate very scientifically. I can tell you that the exterior of a F3 comstar's sprocket carrier looks identical to exterior of K7/8 sprocket carrier, at least to casual observation. I did not pull any carriers out of the hub to compare. We do know that an early sprocket carrier will fit a K7/8 hub and vice versa and that early hub and K7/8 hub are essentially the same, only the sprocket carrier is wider on K7/8.
I would check to see if F2/3 and K7/8 have the same part number for cush drive rubbers. If yes, I think you are golden, if no it is not necessarily conclusive given all of Honda's part number funny business.

So i did some poking around in parts fiches

not only do the cush drive rubbers have the same part number, but the whole sprocket carrier itself is the same part on the F2/3 and the K7/8.

So if an early carrier definitely fits a K7/8, then it looks like it should fit the F2/3 wheel

Now I just hope the F2/3 brake bracket will be the correct width for this setup. I'd rather not use the F1 giant rear brake setup.

Jerry Rxman Griffin aka MuthaF'er · « **Reply #71 on:** December 08, 2015, 10:17:08 AM »

Yeah, carriers are the same. 76 and earlier are all the same and 77/78 are all the same. You'll find that the fiches may just be your new best friend. I use Motogrid.com mostly. That and my 2 parts manuals. Remember that the numbers are often superseded and the online fiches can verify that info.

F2/F3 brake bracket?? Which part are you referring to? caliper, link, ??

riffman12 · « **Reply #72 on:** December 09, 2015, 09:00:18 AM »

Quote from: Jerry Rxman Griffin aka MuthaF'er on December 08, 2015, 10:17:08 AM

F2/F3 brake bracket?? Which part are you referring to? caliper, link, ??

So the F1 has that big dual caliper rear brake caliper. And half of the caliper os integrated into the bracket. This piece specifically:

But I have the rear brake from an F2/3. The rear caliper bracket looks like this:

I'm wondering if the 2 pieces are the same thickness at the axle. ie will I be able to use my F2/3 bracket in my F1 swingarm

SOHC4 Cafe Racer Fan · « **Reply #73 on:** December 09, 2015, 09:10:21 AM »

More important than the thickness is the offset of the caliper to the rotor. Each issue can be addressed with spacers and/or milling off extra material.

madmtnmotors · « **Reply #74 on:** December 09, 2015, 10:11:31 AM »

I have an example of each and can do a mock fit up for both and will let you know. Might not be until the weekend though!

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Author Topic: 1976 CB750F - first bike, first build - mild cafe (Read 36490 times)