99 Nighthawk Countershaft seal Replacement

DDCCWW

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No experience with this issue here...bye.

image.jpg

Pls delete.
 
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amc49

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There is a countershaft bearing cover that removes under the outer case cover. Likely need the gasket there for spacing of bearing.
 

amc49

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Yes.

If you think you can get seal out without yanking cover fine but a lot of butchery begins that way. I'd look at the seal. Honda sometimes makes one part of the OD bigger to either go in a certain way or to have to split cases to get seal in. No splitting there but I'd make sure the seal did not have a stepped OD. Then you can go ahead with trying to pull seal only.

Honda also commonly uses the back of that seal to hold oil pressure for that bearing on other engine designs and it can leak VERY easy as a result of that, has to be installed perfectly.
 

no0bi1

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I see you say the cases have to be split on the DOHC engines on the other threads for this issue

http://www.cb750.com/threads/3800-1980-CB750K-Drive-Sprocket-Oil-Seal-Replacement

http://www.cb750.com/threads/4150-Countershaft-seal-split-the-case?highlight=Countershaft

The part number for the outer Counter shaft seal DOHC is 91206-MJ0-005

It does have a lip on inner diameter but it is pretty soft and I feel like it would slide onto the counter shaft Groove if i punched it in with a big socket

Please advise
 

amc49

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Any lip forcing cases to split is on the OD not ID, and different design engine anyway. A normal seal has both an inside and outside lip in the inner diameter.

I'd remove that cover if mine simply to make sure of getting the seal in right. Putting them in not so much a problem, it's removing them. If you so much as scratch the OD aluminum bore or the inner spacer/distance collar the seal seals on you have leaks. If the distance collar has a wear groove from dirt riding there all the time you will already have a problem, the collar then needs to change too. A socket will work as install tool but I've seen plenty of people use the wrong size to wreck the seal instantly. The socket MUST be over the outer wall (OD), not deeper into the seal (between the OD and ID is death, the seal bends like tinfoil there).

Having changed literally a thousand seals on different things I for one can get the seal out without yanking the cover but your skills there not mine. No insult intended at all there. If you think you can do it then go for it, I do not know how good you are.

Clean the outside off good first, you are breaking into an oil reservoir there and any trash you put in the pocket has to go through bearing to get out. Another possible reason to yank the whole cover.

Luck...........
 

Fetus9

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I have an 80 Cb750 custom that had the countershaft seal give up the ghost. I was able to get the seal out (a pain but doable) getting the new one in is proving to be not so easy nor cheap and out of my skill set. Tried having it put in without cracking it open but failed miserably. Afraid this is going to force me to put the bike on the shelf unless someone here has some ideas. $30 part sad to throw it in storage for who knows how long.
 

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