Author Topic: CB750: Side to side play at rear axle  (Read 2069 times)

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Offline zeech

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CB750: Side to side play at rear axle
« on: October 22, 2013, 12:19:15 AM »
I pieced together a Super Sport rear end from parts off eBay:

1) Swing arm
2) Complete rear axle and all hardware
3) Rear disc brake mount/caliper

Now I'm having some side to side play when I have the axle nuts tightened as far as they will possibly go, almost like I'm out of thread on the nut side. I just realized I don't have any washers on the far outside ends of the bolt head and nut, maybe that's all it is? It seems 2 washers might do the trick. Would new bearings and seals do anything?

See the pic below for where the chain tighteners aren't getting fully flattened and are causing the play.

« Last Edit: October 22, 2013, 12:22:21 AM by zeech »

Offline spazz1984

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Re: CB750: Side to side play at rear axle
« Reply #1 on: October 22, 2013, 12:33:05 AM »
You may have the wrong spacers or just the wrong one on the inside of sprocket hub

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« Last Edit: October 22, 2013, 12:36:14 AM by spazz1984 »

Offline 70CB750

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Re: CB750: Side to side play at rear axle
« Reply #2 on: October 22, 2013, 01:50:55 AM »
+1

Did you check your assembly against a schema like the one at CMSNL?
Prokop
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Offline madmtnmotors

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Re: CB750: Side to side play at rear axle
« Reply #3 on: October 22, 2013, 03:53:05 AM »
Verify the sprocket hub as well. F2/F3 and K7/K8 had a 10mm wider sprocket hub than the earlier models.
TAMTF...


Wilbur



Projects:
"Evolution": http://forums.sohc4.net/index.php?topic=100352.0
"P.O. Debacle": http://forums.sohc4.net/index.php/topic,126692.msg1441661.html#msg1441661
F2/F3 O-rings: http://forums.sohc4.net/index.php?topic=113672.msg1300721#msg1300721
Cam Tower Studs: https://www.mcmaster.com/#93210a017/=t19sgp
Clean up that nasty harness: http://forums.sohc4.net/index.php?topic=137351.msg1549191#msg1549191
http://forums.sohc4.net/index.php/topic,148188.msg1688494.html#msg1688494
http://forums.sohc4.net/index.php/topic,139544.msg1579364.html#msg1579364
                                          
Charging system diagnosis: http://forums.sohc4.net/index.php?topic=1012.msg8345#msg8345
Get the manuals: http://manuals.sohc4.net/cb750k/
The Dragon: http://forums.sohc4.net/index.php?topic=45183.msg1571675#msg1571675
Headlight Switch: http://forums.sohc4.net/index.php?topic=113986.msg1283236#msg1283236
Branden's leak free top end thread: http://forums.sohc4.net/index.php?topic=107040.0
Engine Lifting Made Easy: http://forums.sohc4.net/index.php/topic,58210.msg1684742.html#msg1684742
                                      http://forums.sohc4.net/index.php/topic,100352.msg1675840.html#msg1675840
Static and Dynamic Timing: http://www.hondachopper.com/garage/carb_info/timing/timing1.html
Airbox Gasket Replacement: http://forums.sohc4.net/index.php/topic,114485.msg1290000.html#msg1290000
"Café" : http://forums.sohc4.net/index.php/topic,84697.msg953814.html#msg953814
PD Carb Choke Linkage: http://forums.sohc4.net/index.php/topic,100352.msg1669248.html#msg1669248
                                    http://forums.sohc4.net/index.php/topic,110931.msg1248354.html#msg1248354
                                    http://forums.sohc4.net/index.php/topic,48858.msg515204.html#msg515204
Follow up on your damn posts: http://forums.sohc4.net/index.php/topic,144305.msg1791605.html#msg1791605
Taiwanese Cam Chain Tensioners:  http://forums.sohc4.net/index.php/topic,155043.msg1774841.html#msg1774841
Gumtwo Seat Cover: http://forums.sohc4.net/index.php/topic,164440.msg1897366.html#msg1897366
Primary Drive: http://forums.sohc4.net/index.php/topic,166063.msg1919278.html#msg1919278
Tank Latch: http://forums.sohc4.net/index.php/topic,165975.msg1919495.html#msg1919495
Shorten your forks: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-shorten-forks-td4042465.html DO NOT CUT THE SPRINGS!
Clutch How To: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-change-and-adjust-a-clutch-SOHC-td4040391.html
Late model K7/K8/F2/F3 front sprocket cover removal: http://forums.sohc4.net/index.php/topic,178428.msg2072279.html#msg2072279
630 to 530 conversion: http://forums.sohc4.net/index.php/topic,180710.msg2094423.html#msg2094423

Sent from my Tandy TRS-80!

Offline 70CB750

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Re: CB750: Side to side play at rear axle
« Reply #4 on: October 22, 2013, 04:15:47 AM »
I think Wilbur got it.
Prokop
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I love it when parts come together.

Dorothy - my CB750
CB750K3F - The Red
Sidecar


CB900C

2006 KLR650

Offline madmtnmotors

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Re: CB750: Side to side play at rear axle
« Reply #5 on: October 22, 2013, 05:10:33 AM »
I think Wilbur got it.

That sprocket looks mighty close to the hub....

I believe the later hub used a different inner spacer behind the hub as well.
TAMTF...


Wilbur



Projects:
"Evolution": http://forums.sohc4.net/index.php?topic=100352.0
"P.O. Debacle": http://forums.sohc4.net/index.php/topic,126692.msg1441661.html#msg1441661
F2/F3 O-rings: http://forums.sohc4.net/index.php?topic=113672.msg1300721#msg1300721
Cam Tower Studs: https://www.mcmaster.com/#93210a017/=t19sgp
Clean up that nasty harness: http://forums.sohc4.net/index.php?topic=137351.msg1549191#msg1549191
http://forums.sohc4.net/index.php/topic,148188.msg1688494.html#msg1688494
http://forums.sohc4.net/index.php/topic,139544.msg1579364.html#msg1579364
                                          
Charging system diagnosis: http://forums.sohc4.net/index.php?topic=1012.msg8345#msg8345
Get the manuals: http://manuals.sohc4.net/cb750k/
The Dragon: http://forums.sohc4.net/index.php?topic=45183.msg1571675#msg1571675
Headlight Switch: http://forums.sohc4.net/index.php?topic=113986.msg1283236#msg1283236
Branden's leak free top end thread: http://forums.sohc4.net/index.php?topic=107040.0
Engine Lifting Made Easy: http://forums.sohc4.net/index.php/topic,58210.msg1684742.html#msg1684742
                                      http://forums.sohc4.net/index.php/topic,100352.msg1675840.html#msg1675840
Static and Dynamic Timing: http://www.hondachopper.com/garage/carb_info/timing/timing1.html
Airbox Gasket Replacement: http://forums.sohc4.net/index.php/topic,114485.msg1290000.html#msg1290000
"Café" : http://forums.sohc4.net/index.php/topic,84697.msg953814.html#msg953814
PD Carb Choke Linkage: http://forums.sohc4.net/index.php/topic,100352.msg1669248.html#msg1669248
                                    http://forums.sohc4.net/index.php/topic,110931.msg1248354.html#msg1248354
                                    http://forums.sohc4.net/index.php/topic,48858.msg515204.html#msg515204
Follow up on your damn posts: http://forums.sohc4.net/index.php/topic,144305.msg1791605.html#msg1791605
Taiwanese Cam Chain Tensioners:  http://forums.sohc4.net/index.php/topic,155043.msg1774841.html#msg1774841
Gumtwo Seat Cover: http://forums.sohc4.net/index.php/topic,164440.msg1897366.html#msg1897366
Primary Drive: http://forums.sohc4.net/index.php/topic,166063.msg1919278.html#msg1919278
Tank Latch: http://forums.sohc4.net/index.php/topic,165975.msg1919495.html#msg1919495
Shorten your forks: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-shorten-forks-td4042465.html DO NOT CUT THE SPRINGS!
Clutch How To: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-change-and-adjust-a-clutch-SOHC-td4040391.html
Late model K7/K8/F2/F3 front sprocket cover removal: http://forums.sohc4.net/index.php/topic,178428.msg2072279.html#msg2072279
630 to 530 conversion: http://forums.sohc4.net/index.php/topic,180710.msg2094423.html#msg2094423

Sent from my Tandy TRS-80!

Offline zeech

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Re: CB750: Side to side play at rear axle
« Reply #6 on: October 22, 2013, 01:46:33 PM »

That sprocket looks mighty close to the hub....

I believe the later hub used a different inner spacer behind the hub as well.
Verify the sprocket hub as well. F2/F3 and K7/K8 had a 10mm wider sprocket hub than the earlier models.


What and how do I verify? The rear wheel, hub and sprocket is how it came.

Offline jpfrk2001

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Re: CB750: Side to side play at rear axle
« Reply #7 on: October 22, 2013, 02:08:46 PM »
You could add a washer to each side sandwiched between the adjuster and hub. Then just verify the alignment of the chain sprockets. These are just thoughts at a whim. As mentioned, different size hubs could cause a problem.

From the pics, I can tell that you are forcing the swing arm together. So it is not squared up. Looks scary to me.
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Offline 70CB750

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Re: CB750: Side to side play at rear axle
« Reply #8 on: October 22, 2013, 02:10:12 PM »
CycleX has info on those hubs,check them out.

http://www.cyclexchange.net/Chain%20Sprocket%20Page.htm
Prokop
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Pure Gas - find ethanol free gas station near you

I love it when parts come together.

Dorothy - my CB750
CB750K3F - The Red
Sidecar


CB900C

2006 KLR650

Offline zeech

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Re: CB750: Side to side play at rear axle
« Reply #9 on: October 22, 2013, 02:10:58 PM »
Yea it's definitely flexing in a bit. Much more than it should be.

Not sure how to fix the issue... I'm sure there are proper spacers out there, but not entirely sure which will fit.

Offline zeech

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Re: CB750: Side to side play at rear axle
« Reply #10 on: October 22, 2013, 02:15:41 PM »
CycleX has info on those hubs,check them out.

http://www.cyclexchange.net/Chain%20Sprocket%20Page.htm

That looks like it might be the ticket. I'll measure when I get home. It looks like I might need to track down a 36mm hub... Ugh  :o
« Last Edit: October 22, 2013, 02:23:25 PM by zeech »

Offline zeech

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Re: CB750: Side to side play at rear axle
« Reply #11 on: October 23, 2013, 11:16:26 AM »
Thanks very much for the help guys, the hub info really helped. Turns out the wheel I was using had a smaller hub, but I still had the original wheel from the bike so I was able to swap the hubs and it then went together perfectly tight with minimal tightening.

Really love this site and how helpful it is. Many of us would be lost without it.

Offline 70CB750

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Re: CB750: Side to side play at rear axle
« Reply #12 on: October 23, 2013, 11:26:21 AM »
Cool!
Prokop
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Pure Gas - find ethanol free gas station near you

I love it when parts come together.

Dorothy - my CB750
CB750K3F - The Red
Sidecar


CB900C

2006 KLR650