Author Topic: 75 F rear brake pulling  (Read 2183 times)

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Offline Que75cb750

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75 F rear brake pulling
« on: July 13, 2016, 05:58:24 PM »
I just picked up a 75 750f for a project, I've been driving it around a bit to get a feel for its overall condition before I tear her down this coming winter. I found that when coming to a stop and using the rear disc brake I feel it pulling a bit to the right, as if the axle is loose and and going out of alignment, that is not the problem as everything is all tight , is it possible a worn swing arm bushing is worn? Maybe the rear brake stabilizing arm is worn? Any suggestions?

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: 75 F rear brake pulling
« Reply #1 on: July 13, 2016, 06:55:06 PM »
I bought mine new and have never felt a pull?? Shouldn't be the 'stabilizing' arm. Stock swing bushings are a bakelite type material and we usually replace with bronze. Wheel ball bearings?
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline Que75cb750

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Re: 75 F rear brake pulling
« Reply #2 on: July 13, 2016, 07:06:53 PM »
The bike has 58000miles and I suspect the previous owner , who has owned it since 76, wasn't all that good with maintenance so I don't imagine he ever greased the swing arm. Maybe someone who has experienced this will chime in with there observations and solutions

Offline david 750f

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Re: 75 F rear brake pulling
« Reply #3 on: July 13, 2016, 08:35:18 PM »
I've had horribly worn out swing arm bushings on my 76 750F and the bike has never pulled to one side. Check the swing arm bolt, axle bolt and chain adjusters. As well as the bolts/nuts on the rear torque arm.
1976 CB 750F

Offline Que75cb750

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Re: 75 F rear brake pulling
« Reply #4 on: July 14, 2016, 03:17:29 AM »
This weekend I will take a closer look at it. I maybe explaining the problem wrong, I should say that when the back brake is first applied the back will squat and seems to twist or pull the back end to the right. Sort of feels at first like the wheel will lock up but doesn't and its all good after that first 'squat' or grabbing sensation. I ran the bike on the center stand in 2nd pulled the clutch and jammed on the brake on hoping to see something loose but all looks good.

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: 75 F rear brake pulling
« Reply #5 on: July 14, 2016, 09:38:02 AM »
With that in mind Honda decided to use a double xxx, err double PISTON, on the rear of the 75/76 F instead of the front. Kinda got that backwards. Changed that with the 77/78 F. It is really too much brake for the rear and can lock up in a heartbeat. Try that with a worn out tire and the rear end will slide all over the place. Use the rear easy. 
« Last Edit: July 14, 2016, 11:06:36 AM by Jerry Rxman Griffin aka MuthaF'er »
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline WaxhawFive

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Re: 75 F rear brake pulling
« Reply #6 on: July 14, 2016, 09:46:01 AM »
I've never seen a double-disc rear on a CB750F, are you sure about that?
1975 CB550F Super Sport

Offline riffman12

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Re: 75 F rear brake pulling
« Reply #7 on: July 14, 2016, 09:49:11 AM »
I think Jerry means dual piston, not dual disk

Offline madmtnmotors

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Re: 75 F rear brake pulling
« Reply #8 on: July 14, 2016, 09:51:11 AM »
With that in mind Honda decided to use a double disc on the rear of the 75/76 F instead of the front. Kinda got that backwards. Changed that with the 77/78 F. It is really too much brake for the rear and can lock up in a heartbeat. Try that with a worn out tire and the rear end will slide all over the place. Use the rear easy. 


I've never seen a double-disc rear on a CB750F, are you sure about that?


LOL.

Where would you put the sprocket?  ???


I think Jerry means dual piston, not dual disk

They still only had a single piston too...  ;)
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
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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

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Offline riffman12

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Re: 75 F rear brake pulling
« Reply #9 on: July 14, 2016, 09:56:24 AM »
They still only had a single piston too...  ;)

hmmmm?

I count 2


Offline flybox1

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Re: 75 F rear brake pulling
« Reply #10 on: July 14, 2016, 10:01:57 AM »
Dual Pistons  :P

The bike has 58000miles and I suspect the previous owner , who has owned it since 76, wasn't all that good with maintenance so I don't imagine he ever greased the swing arm. Maybe someone who has experienced this will chime in with there observations and solutions
rear axle locating screws....are these lock nutted in place?
Worn shoes pads  :P
rear wheel bearings
rear stabilizer arm
swing arm bushings
loose spokes.

« Last Edit: July 14, 2016, 11:26:51 AM by flybox1 »
'78 750K (F3 engine) PD42b's, Modified airbox w/K&N  filter, 40/110 jets, 1 needle shim, IMS@ 1 turn out. Kerker + Cone 18" QuietCore

Past Bikes
1974 550K0 (stock), 1973 CB350F (stock), 1983 Yamaha XS400K (POS)
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"Knowledge without mileage equals bullsh!t" - Henry Rollins

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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: 75 F rear brake pulling
« Reply #11 on: July 14, 2016, 11:09:11 AM »
Thanks for the correction!!

Yes I meant double PISTON and yes they have 2 PISTONS LOL. I was taking a break from painting my basement. Guess my mind was still there haha.

However no SHOES Fly, pads.

And just a FYI, a complete rebuild kit is available from SiriusConInc.com which includes 2 new pistons should the need arise.
« Last Edit: July 14, 2016, 11:11:24 AM by Jerry Rxman Griffin aka MuthaF'er »
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline madmtnmotors

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Re: 75 F rear brake pulling
« Reply #12 on: July 14, 2016, 11:16:02 AM »

Yes I meant double PISTON and yes they have 2 PISTONS LOL.


I stand corrected. I was thinking of the F2 and had to refer to the parts fiche to discover that the F0/F1 did indeed use a dual piston caliper.  8)

You guys will teach me something yet!  :o  ;)
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 Que75cb750

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Re: 75 F rear brake pulling
« Reply #13 on: November 18, 2016, 03:15:58 AM »
Sorry for getting back to this so late and thanks for all the replies. The problem was worn chain adjuster. I guess the previous owner didn't realize the problem or just lived with it but I guess over time with the axel moving back and forth during braking and acceleration the adjuster axle hole wore oval, it's all good now except for the weather ,looks like I had my last ride of the season last week.