Topic: OIL on a clean engine: 750 k4 tach cable leak

[andrewraffaele]

Dear all,

Oil is bleeding out of my valve cover where the tachometer cable plugs into the engine. I'm riding a 1974 CB750, 13k miles and a super clean engine otherwise... any way I can keep her a little more tidy?

Thank ya,

Andrew

[dhall57]

Just replace the tach seal. Honda still has them, but use the one for early dohc 750 instead of the sohc seal. It's a fraction larger so it seals better. I've had to replace both on my 750KO and K6.

[cookindaddy]

Happened to me also. Using the Honda seal for the SOHC works fine, no oil leakage here after I replaced mine.

[thrutheframe]

Ditto... The hardest part is getting the screw out.  If the screw looks boogered just order the screw when you order the seal,  little touches like that go a long way.

[Roach Carver]

Well, im a moron. Ive never replaced one but I have a leak in one engine. I pulled the tach cable and saw no seal. I just figured it was inside the valve cover as that is my usual luck. Where is it?!

[dhall57]

I guess its possibly yours is missing. If the leak is bad that would explain it. The seal is recessed in the valve cover maybe a 1/2" or so get a flash light and be sure its in there and see if you see the top of the seal. It can be a little tricky getting it out so I get a very small drill bit and drill very carefully into the top on one side of the seal. Don't go very deep into the seal just enough so you can screw a small screw into top of seal. A couple turns is all it takes. Than take some needle nose pliers and grab the screw an pull the seal out.

[Pecantree]

You can also take a 2" or so drywall screw and screw it into the rubber of the seal and pull it out with pliers.
Also use a socket, I think 9mm to seat the seal.
I've "heard" of someone thinking the seal was gone and installing a second seal on top of the first
I'd never heard about the dohc seal. I'll have to do that next time.
Good Luck
Steve

[thrutheframe]

You can also take a 2" or so drywall screw and screw it into the rubber of the seal and pull it out with pliers.
Also use a socket, I think 9mm to seat the seal.
I've "heard" of someone thinking the seal was gone and installing a second seal on top of the first
I'd never heard about the dohc seal. I'll have to do that next time.
Good Luck
Steve

On my 750K4 I looked in the hole three times but never saw the seal.  Its hard to see down in there.  I didnt quite install the second seal but it was close.  Stick a pick tool in there and probe around, you'll be able to tell solid metal from a rubber seal.