Author Topic: CB750A tranny klinking and klanking  (Read 439 times)

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Offline jukku

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CB750A tranny klinking and klanking
« on: September 19, 2019, 10:30:20 am »
Broken vibration damper springs on Honda CB750A Hondamatic.
Noice from the tranny when gear is engaged.

https://1drv.ms/v/s!AvgjL1lJG5iElNhh70pL3R76VM2Eew?e=QtLZQ7


Offline vik351

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Re: CB750A tranny klinking and klanking
« Reply #2 on: September 19, 2019, 09:30:08 pm »
didnt sound too good, be buggered if I woulda ran it that long with that noise...

How much of a fun job replacing those springs...???

Ya will replace them all at the same time I presume...???

I only get my bikes next week so then I can have a listen to them...  :'(

vik...goodluck...

Offline 05c50

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Re: CB750A tranny klinking and klanking
« Reply #3 on: September 20, 2019, 04:27:05 am »
Thanks for sharing the video and the repair. My A makes a similar noise, but is worse in neutral. It goes away in gear. Was a complets disassembly  necessary to replace the springs ?

.....Paul
Wear a helmet,the life you save may be your own.Ask me how I know.               CB650C,CB550F,GL1000,CB750A

Offline sammon287

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Re: CB750A tranny klinking and klanking
« Reply #4 on: September 20, 2019, 10:27:36 am »
Thanks for sharing the video and the repair. My A makes a similar noise, but is worse in neutral. It goes away in gear. Was a complets disassembly  necessary to replace the springs ?

.....Paul

Mine was similar to yours. I didn't know these springs breaking was a thing until I took everything apart and found them in pieces. Unfortunately, it does require a complete engine/transmission tear down to get to them. I'm replacing all plain bearings and seals. I'm reusing transmission ball bearings, the clutch disks, and the primary chain guides. One of the primary chain guides is very expensive and the other is unobtainable. They look OK, so I'm hoping they don't disintegrate after my long and expensive rebuild. I'm also hoping the replacement damper springs hold up better.
1976 CB750A

Offline raymond10078

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Re: CB750A tranny klinking and klanking
« Reply #5 on: September 20, 2019, 10:28:08 am »
Some noises are only the result of carbs not synced well and/or idle speed set too low.

Mine had exactly this issue, and no noise since.
1978 CB750A (upgrading very, very slowly)

Past bikes - Honda: SL350, CX650C, CB900C, CB1000C, CM450A; Kawasaki: several 1972 750 H2's; Suzuki: TC90J.

Bikes I want: CX650ED, a mid-sized japanese V-twin with ABS.

Offline ORAZIO

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Re: CB750A tranny klinking and klanking
« Reply #6 on: March 24, 2020, 03:39:42 pm »
 
Broken springs.
My solution to avoid that some pieces of springs go between the gears.
I inserted a 6.35 mm section of Oring in the springs in order to retain any broken rings.
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20200221-174955" border="0
« Last Edit: March 24, 2020, 03:41:44 pm by ORAZIO »

Offline MRieck

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Re: CB750A tranny klinking and klanking
« Reply #7 on: March 27, 2020, 05:54:45 pm »
 They all break.......no matter what they are used for. Street, dragracing etc etc etc. They all break.....every time.
Owner of the "Million Dollar CB"

Offline PeWe

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Re: CB750A tranny klinking and klanking
« Reply #8 on: March 28, 2020, 01:22:14 am »
Wvat more can cause vibrations on a CB750A?
Bike vibrates a lot when riding from around 50 mph and rising.
Problems holding the handle bar.
No specific noise at idle.
These springs replaced. Converter replaced too. Same vibrations.

A friend has a CB750A -77 (Japanese stickers) in mint condition he has tried to figure out what cause these vibrations.
« Last Edit: March 28, 2020, 01:40:25 am by PeWe »
CB750 K6-76 1005cc JMR Billet block.
CB750 K2-75 Parts assembled to stock K2

Offline vik351

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Re: CB750A tranny klinking and klanking
« Reply #9 on: March 28, 2020, 04:02:18 am »
I had a K2 back in the 70's and this is my first mike since then, 40 odd years, I recokn my 750A has more vibes that I can remember from the K2, but just in the frame, not the bars.

The K2 had bad speed wobbles but that was right up there 70-80 mph

??? weird one... good luck, ask on the main forum perhaps...???

vik...

 

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