Topic: cb550 crank seal re-replacement

[7]

After a summer of tear down and rebuild my '75 cb550 is back together and running strong. During this tear down I split the case and replaced all the seals. EVERYTHING!! This bike had a ton of small leaks which caused the engine to be constantly weeping oil. Good news... 99% of the leaks are fixed. Bad news... that's not 100%. The left side crank seal is leaking at the dynamic seal. Funny enough is it only happens when you lean it over left and oil pools there. Either way, another seal needs to go in. Does anyone know if the engine can be flipped upside down and the bottom half lifted high enough to get this seal out? After all the top end work I did I'm really hoping to leave that alone.

Thanks!!

[Killer Canary]

Do you mean that the replacement seal has a shoulder like the stock seal had?

[BomberMann650]

Sure it’s not the oil galley press fit cap that’s weeping?

[DaveBarbier]

You can flip the motor and replace the seal. The bottom case half can be removed completely. But for that the primary shaft will have to be removed to free the primary chain. Not an issue. The crank may need to be lifted a bit as well to free the seal.

I would get an oem seal with a lip and maybe add a bit of hondabond and seal it up before it cures. I installed my seals dry and on both my motors they're bone dry.


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[DaveBarbier]

Sure it’s not the oil galley press fit cap that’s weeping?

Good call, could be that. Not sure if you're certain it's the seal. Cleaning and sprinkling with baby powder can help find the source.

[7]

Sorry all for the very very delayed response. Yes it is the crank seal. I machined a piece of plate steel to hold the plug in and check the oil passage seal. Oil is leaking from the ID dynamic seal on the crank. The replacement I used was OEM old stock. Obviously didn’t notice any defects when installing but clearly something wants right. I’ll update once it replaced in the spring.

[7]

You can flip the motor and replace the seal. The bottom case half can be removed completely. But for that the primary shaft will have to be removed to free the primary chain. Not an issue. The crank may need to be lifted a bit as well to free the seal.

I would get an oem seal with a lip and maybe add a bit of hondabond and seal it up before it cures. I installed my seals dry and on both my motors they're bone dry.

Thanks. This is exactly the info I was hoping for. I really don’t want to tear into the top end again after all the work that went into making it right.