Author Topic: Wrong axle &/or wrong swingarm..or brake backing plate? (Read 6402 times)

Johnny340 · « **Reply #25 on:** June 13, 2018, 09:34:20 PM »

Ok I have the correct sprocket carrier and it's internal spacer now, plus I know the left side spacer width.
All I need to know is the width of the spacer on the other side. Anyone? It's #10 in this picture ('72 CB750).

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bryanj · « **Reply #26 on:** June 15, 2018, 07:06:50 AM »

As you probably found the 500 will not fit but if the drum is not cracked you should be able to sell it as 500/550 ones do crack the liners

Johnny340 · « **Reply #27 on:** June 20, 2018, 01:47:59 PM »

With the correct sprocket carrier and the long spacer I see that the wheel is 30mm to the right. That long spacer is only 10mm longer than what is supposed to be there. Is the spacer on the right supposed to be 20mm? That would result in the wheel being close to centered.

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754 · « **Reply #28 on:** June 20, 2018, 03:05:08 PM »

Chainside spacer is too long. Early swingarm too, but can work with offset. Yes 10mm, that is the difference.. running out to see if I can measure..brb..

Ok brake side looks like 28 mm long..
Chain side has about 1/4 or less between chain adjuster and the bulge on your sprocket carrier ..like 4 or 5 mm showing.

Your brake panel backing plate looks a bit funny to me, I think the usually have a bit of a lip going toward the hub.?

Johnny340 · « **Reply #29 on:** June 20, 2018, 03:20:14 PM »

Quote from: 754 on June 20, 2018, 03:05:08 PM

Chainside spacer is too long. Early swingarm too, but can work with offset. Yes 10mm, that is the difference.. running out to see if I can measure..brb..

Ok brake side looks like 28 mm long..
Chain side has about 1/4 or less between chain adjuster and the bulge on your sprocket carrier ..like 4 or 5 mm showing.

Your brake panel backing plate looks a bit funny to me, I think the usually have a bit of a lip going toward the hub.?

Hmm... with 5mm sticking out on the chain side there is no way I'd be able to fit a 28mm spacer on the brake side. So that backing plate looks wrong? Could it have too much thickness to it?
Here's another pic.

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754 · « **Reply #30 on:** June 20, 2018, 03:29:06 PM »

Where the backing plate meets the hub, does not look right, neither does the outer edge of backing plate.
Run the nut on the axle with your fingers, do the cutter pin holes line up?

754 · « **Reply #31 on:** June 20, 2018, 03:35:20 PM »

Post 8 and 9 show what it should look like.
Your brake plate appears like it needs to be 8 or10 mm further in.. not sure what ix holding it out.

Johnny340 · « **Reply #32 on:** June 20, 2018, 04:21:34 PM »

It seems to tighten up ok but yes there is an extra ring on the hub itself. The backing plate looks and works ok to me but I need to make that spacer. So 20mm? And then I'll thin the left one.

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754 · « **Reply #33 on:** June 20, 2018, 04:39:13 PM »

For starters, put the spacer from the sprocket side on the brake side, and nothing in sprocket for now.
When you drop the wheel pull the backing plate, something tells me your bearing or something is sticking out a bout 8 mm to the brake side, get a pic.
What did you use for a center spacer?

Not sure how you got this far out, I mean looking at the manual pics and post 8 and 9 shows it all.

seanbarney41 · « **Reply #34 on:** June 20, 2018, 04:55:22 PM »

the brake plate is supposed to fit inside the id of the drum...is that even a cb750 hub?

Johnny340 · « **Reply #35 on:** June 20, 2018, 05:01:27 PM »

Quote from: seanbarney41 on June 20, 2018, 04:55:22 PM

the brake plate is supposed to fit inside the id of the drum...is that even a cb750 hub?

I don't know. I bought it from a friend who was dying of Cancer. He was restoring this CB750 but who knows what hub this is. He's not around to ask anymore..

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754 · « **Reply #36 on:** June 20, 2018, 08:24:40 PM »

It had a 500 sprocket on it .. right
So it may be a 500 hub, which is not as deep for the wider 750 brake shoes..
Makes the brake shoes and plate stick out to far.. that has to be it..
Looks like a 500 hub.

BobR · « **Reply #37 on:** June 21, 2018, 03:44:11 PM »

Yeah as 754 stated the hub looks "wrong" or nothing like my K4 hub I posted a pic of. Bob

Johnny340 · « **Reply #38 on:** June 22, 2018, 04:05:23 PM »

Quote from: 754 on June 20, 2018, 04:39:13 PM

For starters, put the spacer from the sprocket side on the brake side, and nothing in sprocket for now.
When you drop the wheel pull the backing plate, something tells me your bearing or something is sticking out a bout 8 mm to the brake side, get a pic.
What did you use for a center spacer?

Not sure how you got this far out, I mean looking at the manual pics and post 8 and 9 shows it all.

OK so I'm back to the rear wheel. I can't try the left spacer on the opposite side because 15mm of it fits inside the hub (held by the dust seal). Is that the correct amount? Frank when you had 28mm on the brake side, how much was sticking out the drive side? Here are a couple pics of the inside of the brake. The bearing seems to be seated ok in the hub and the backing plate actually fits well imo. Its just that mystery groove in the outside of the hub itself which doesn't affect the fitment but looks odd and may not be from any 750??
As for the spacing, it's close. I'll never be able to fit a 28mm spacer in the brake side since only 20mm is sticking out the drive side now. I could narrow the drive side spacer by 15mm and make a 15mm spacer for the brake side which would center the wheel and likely line up the chain line. Thoughts?

754 · « **Reply #39 on:** June 22, 2018, 04:20:20 PM »

I said 4 or 5 mm on chainside, just pull the spacer out.

Take a tape or pencil to your hub as shown in your today pics, measure the width of the brake lining.
Then compare that to the 750 shoe width. 500 hubs are not as deep.

In the future, assemble and check fit of every assembly before polishing or painting, save a lot of grief.

Johnny340 · « **Reply #40 on:** June 22, 2018, 04:32:12 PM »

Quote from: 754 on June 22, 2018, 04:20:20 PM

I said 4 or 5 mm on chainside, just pull the spacer out.

Take a tape or pencil to your hub as shown in your today pics, measure the width of the brake lining.
Then compare that to the 750 shoe width. 500 hubs are not as deep.

In the future, assemble and check fit of every assembly before polishing or painting, save a lot of grief.

I was asking how much went into the hub thinking maybe that bearing wasn't in enough. Mine goes in 15mm so I need that one 20mm to give that 5mm sticking out. As for the other side, I'll never fit 28mm there so either the swingarm is bent or the hub is wrong. The braking material is 40mm exactly like the matching surface in the hub.
The outside horizontal part of my hub from the edge to the outside including my grooves is 21mm. (from the 'corner' to the edge...does that make sense?) Is that normal for a 750? It looked like Bob's pic was similar but without the grooves.

I agree on the polishing first...I have other parts powder coated too early as well. Again, not my project to start with but I'm going to finish it!

754 · « **Reply #41 on:** June 22, 2018, 04:53:41 PM »

Measure between the ends of swingarm maybe it got dropped or hit.
If you pull your sprocket side spacer, then slide axle thru hub and brakeplate, how much room for spacer on the brake side?
Dont turn the wheel, it may scratch the sprocket side.

Johnny340 · « **Reply #42 on:** June 22, 2018, 05:10:41 PM »

Quote from: 754 on June 22, 2018, 04:53:41 PM

Measure between the ends of swingarm maybe it got dropped or hit.
If you pull your sprocket side spacer, then slide axle thru hub and brakeplate, how much room for spacer on the brake side?
Dont turn the wheel, it may scratch the sprocket side.

235mm between the ends of the chain adjuster tabs where the axle goes through.
Assembled without spacers shows about 20mm extra room.

754 · « **Reply #43 on:** June 24, 2018, 07:09:02 PM »

Ok I measured one at 240mm today, subtract the adjusters, should give 234 ish.
Remember remove sprocket side spacer completely, pull wheel over to sprocket side, but not so it rubs, the see how brake fits and if there is 28 mm for the spacer.

Johnny340 · « **Reply #44 on:** July 04, 2018, 06:13:42 AM »

Quote from: 754 on June 24, 2018, 07:09:02 PM

Ok I measured one at 240mm today, subtract the adjusters, should give 234 ish.
Remember remove sprocket side spacer completely, pull wheel over to sprocket side, but not so it rubs, the see how brake fits and if there is 28 mm for the spacer.

I'm back in town...
Thanks for the measurement Frank!
So my swingarm is not bent. OK, with the wheel pulled over and no spacers at all I see about 21mm of free space with the brake sitting nicely. So with 5mm required to stick out on the drive side I'm seeing room for maybe a 16mm spacer on the brake side. Is it that simple? Here are a couple more pics:

754 · « **Reply #45 on:** July 04, 2018, 07:55:47 AM »

Looks like with 5 or 6mm on the sprocket side you will end up a 16 or a bit more on sprocket side.
I would pull brake plate out of wheel, and check bearing is fully seated. If it is not and you readjust it, everything changes. And make sure your sprocket carrier is seated in when you start measuring.

Johnny340 · « **Reply #46 on:** July 04, 2018, 08:03:11 AM »

OK thanks! I'll double check all of that and then make a spacer.

754 · « **Reply #47 on:** July 15, 2018, 08:57:02 PM »

I need a length for the sprocket side spacer, for 69 to 76.
It's #9 in post #25.
I have the brake side spacer for you, but pretty sure the sprocket one I grabbed is 77 or 78 and longer.
I should have one got to dig a bit more.

754 · « **Reply #48 on:** July 16, 2018, 08:45:16 PM »

Anyone got a spacer they can measure .....as In last post ?

754 · « **Reply #49 on:** July 20, 2018, 08:50:21 PM »

3rd time ..ANYONE got a 69 to 76 750 sprocket side spacer they can measure.
Guy is coming from 4 hrs away, don't want to give him the wrong spacer.. and don't want to drop my wheel to measure mine. Please..

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Author Topic: Wrong axle &/or wrong swingarm..or brake backing plate? (Read 6402 times)