Author Topic: Fork seal replacement failure CB750K1  (Read 378 times)

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Offline Prospect

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Fork seal replacement failure CB750K1
« on: May 14, 2021, 01:08:38 PM »
I replaced the seals last fall. Seemed to go well and I finally took it for a test ride today. The fork seal on one side started leaking immediately. The other side is fine. Not sure what I did wrong so I attached some photos. I've done this work several times without issues so I'm not sure what went wrong. Both the snap ring and the other circular ring are in there.


« Last Edit: May 14, 2021, 01:11:07 PM by Prospect »
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1969 CB750  Sandcast #256
1971 CB750K1
1972 CB750K1
1975 CB400F
1975 GL1000 Goldwing
1954 Harley Davidson Panhead
1957 Harley Davidson Panhead

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Offline pjlogue

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Re: Fork seal replacement failure CB750K1
« Reply #1 on: May 14, 2021, 01:22:17 PM »
It looks like the seal was installed upside down.  Flat side up, spring side down.  Also, the upper area of the fork leg looks kind of rough.  If the seal seating recess is banged up/scratched it can leak from there too.

-P.

Offline PeWe

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Re: Fork seal replacement failure CB750K1
« Reply #2 on: May 14, 2021, 01:36:34 PM »
I have noticed that seals can look different.
The lips should be angled at the oil it stop to leak.
Possible to feel with a finger.

I oiled the upper side with a squirt of oil to ensure lubrication of the top lip so it will not crack too early.
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
CB750 K2-75 Parts assembled to a stock K2

Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
The billet block build thread
http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
Carb jetting, a long story Mikuni TMR32
http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline bryanj

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Re: Fork seal replacement failure CB750K1
« Reply #3 on: May 14, 2021, 01:59:09 PM »
Later seals have a spring top and bottom but if the casing is damaged when getting seal out oil will leak arround outside
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

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