Author Topic: 1976 CB550 crank seal replacement? Split the case or no?  (Read 480 times)

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Offline neurotoxin312

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1976 CB550 crank seal replacement? Split the case or no?
« on: February 20, 2022, 10:02:33 AM »
So after doing some troubleshooting, I realized that I may have a bad crank seal on the stator side of my 1976 cb550k. I tried replacing the o ring on the galley plug, and not I can visibly see a line of oil coming from the crank seal. Bike has been sitting for a few years.

I am reading that I need to split the crankcase in order to replace this seal? Is that actually the case? Will I need to pull the motor from the frame as well? Just want to doublecheck.


Offline bryanj

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Re: 1976 CB550 crank seal replacement? Split the case or no?
« Reply #1 on: February 20, 2022, 10:24:41 AM »
Yes the motor has to come out
Yes the cases have to be spit
Yes the cam has to come out to get enough slack on chain to lift crank as seal has a lip on it
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).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline neurotoxin312

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Re: 1976 CB550 crank seal replacement? Split the case or no?
« Reply #2 on: February 22, 2022, 08:30:15 AM »
Got it. I didn't realize that the crankcase bolts together vertically. That would make this job a lot easier.

Any other parts that I should replace while I'm there? I will be replacing the cam chain.

Offline bryanj

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Re: 1976 CB550 crank seal replacement? Split the case or no?
« Reply #3 on: February 22, 2022, 09:01:12 AM »
Primary chain, search on the forum as a Kawasaki one is the same and a lot cheaper than Honda plus the 8 damper rubbers in the primary drive, still available from Honda, not cheap but need doing with chain plus buy a seal kit and change all of them.
You will need
Oil seal kit, a 500 one has all the main seals the same
Clutch cover gaset
Cam cover gasket/O ring
"Pucks" between cam cover and head
Exhaust to head gasket
Oil and filter
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).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline Little_Phil

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Re: 1976 CB550 crank seal replacement? Split the case or no?
« Reply #4 on: February 23, 2022, 01:58:11 AM »
I think as as hinted at in Bryanj's first response, the seal can be replaced by removing the cam (so you can raise c/s) and then turning the engine over and just removing the bottom half to replace just the seal.

Offline neurotoxin312

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Re: 1976 CB550 crank seal replacement? Split the case or no?
« Reply #5 on: February 23, 2022, 02:07:32 PM »
Do I need to relash the valves after I remove the cam cover? 

Offline jgger

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Re: 1976 CB550 crank seal replacement? Split the case or no?
« Reply #6 on: February 23, 2022, 05:12:07 PM »
Loosen them all before you remove any cover screws. Then look up the rubber band trick before you put it back together. I'm pretty sure the 500/550's require this, someone correct me if I'm wrong.

Yes the valves will need readjustment.
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Offline neurotoxin312

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Re: 1976 CB550 crank seal replacement? Split the case or no?
« Reply #7 on: February 23, 2022, 08:22:02 PM »
Got it. Done. Since I have the engine off I'd like to do a compression test which requires operation of the starter motor. How do I hotwire the starter while the engine's on the stand? I thought grounding the engine block and applying 12 volt power to the starter wire would do it, but the starter motor is not engaging.

Offline bryanj

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Re: 1976 CB550 crank seal replacement? Split the case or no?
« Reply #8 on: February 24, 2022, 04:55:05 AM »
If you put a battery connected neg to egine case and pos to big lead from starter starter should spin or its duff, if it spins but no engine turn starter clutch needs overhaul
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).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!