Author Topic: Tach oil seal  (Read 10882 times)

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Offline cb750fbomb

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Tach oil seal
« on: April 23, 2009, 10:29:54 AM »
So, oil is coming out of my tach cable and I'm assuming theres an oil seal. I found something in the FAQs, but it is for 550's. I know where to get the cable, since it's got a whole in the middle and is leaking oil I should probably change it,  but is the below item correct for my bike? If it's not, could someone clue me in on the part #, link to it or whatever's clever? One last thing. What's involved in changing this seal?

Tach drive oil seal   1    $3.87     $3.87    91211-286-003
'77 CB750F2
“The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at or repair.”

Offline Johnny5

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Re: Tach oil seal
« Reply #1 on: April 23, 2009, 10:39:33 AM »
I just ordered a new one for my 77 750K. But I ordered the tach seal for the DOHC motor on a 79. It's a little beefier.

Carefully screw a woodscrew into the seal and pull it out. Lightly tap the new seal in.
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Offline Porscheguy912

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Re: Tach oil seal
« Reply #2 on: April 23, 2009, 10:43:21 AM »
I just ordered a new one for my 77 750K. But I ordered the tach seal for the DOHC motor on a 79. It's a little beefier.

Carefully screw a woodscrew into the seal and pull it out. Lightly tap the new seal in.

You can use a deep-well socket to tap it in place. Prob an 8mm.
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Offline Johnny5

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Re: Tach oil seal
« Reply #3 on: April 23, 2009, 10:50:45 AM »
Just be cafeful removing the seal and not scratch the bore or she'll leak no matter what you put in there. It's the same logic as replacing the fork oil seals.
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Offline Inigo Montoya

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Re: Tach oil seal
« Reply #4 on: April 23, 2009, 10:55:04 AM »
A screw to remove but the new honda seal I got slipped right in with a slight nudge. 0 leaks. I used my thumb. Been 3 or 4 years sine I did mine and still no leaks from it.
I wonder if the seal fits tighter in the older valve covers. only reason I can see why some have to tap it in.

Offline cb750fbomb

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Re: Tach oil seal
« Reply #5 on: April 29, 2009, 10:47:36 PM »
This was a very easy install, but the reason it was leaking so bad was that the PO didn't even have a d@mn seal in there. I guess the PO liked oil smoke in the headlights at night.
'77 CB750F2
“The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at or repair.”

Offline ev0lve

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Re: Tach oil seal
« Reply #6 on: April 29, 2009, 11:05:45 PM »
I just ordered a new one for my 77 750K. But I ordered the tach seal for the DOHC motor on a 79. It's a little beefier.

Carefully screw a woodscrew into the seal and pull it out. Lightly tap the new seal in.

Hmmm, I just got a new one for mine (K5) - labeled 4.8x14.5x4

Should be off a 78 and looking at cmsnl they have it labeled at that size as well. The 79 has no spec though.

Do you happen to know the 79's size off hand just for the info?

Offline cb750fbomb

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Re: Tach oil seal
« Reply #7 on: April 29, 2009, 11:30:52 PM »
Sorry, but I have no idea. I'm new to bikes so all I know is what I've read here and what I've had to do to my bike and the latter is minimal. Someone might chime in though. I understand, from this thread actually, that they are apparently beefier. You could PM Johnny5. He might know since he just installed one.
'77 CB750F2
“The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at or repair.”

Offline Johnny5

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Re: Tach oil seal
« Reply #8 on: April 30, 2009, 05:02:29 AM »
I installed it last Friday, and it's not much bigger at all. It's just a hair thicker but the diameter was almost exactly the same. The new seal went it really easy. I used a 8mm or 9mm socket and tapped it in.
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Offline Johnie

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Re: Tach oil seal
« Reply #9 on: April 30, 2009, 06:25:00 AM »
For you guys that may be replacing your tach cable, cut the end off the housing and use it to guide the new tach seal in.  Works nice.  This is now part of my metric tool drawer.
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Offline Duke McDukiedook

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Re: Tach oil seal
« Reply #10 on: April 30, 2009, 06:47:43 AM »
Dental pick worked like a charm, the screw didn't work for me.
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Offline Johnny5

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Re: Tach oil seal
« Reply #11 on: April 30, 2009, 07:06:12 AM »
A small screw pulled the seal right out. The seal goes in really easy.
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Offline Johnie

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Re: Tach oil seal
« Reply #12 on: April 30, 2009, 08:53:53 AM »
I had to drill a small hole to be able to get that screw started.  I like the dental pick idea better than using a drill.  I will try that next time.
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

Oshkosh, WI  USA

jerimiah797

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Re: Tach oil seal
« Reply #13 on: August 11, 2009, 05:38:58 PM »
My tach oil seal needs to be replaced. I've got a 78 CB750K. I was just at a shop getting some other stuff and asked the owner about it. He claims that the seal needs to be replaced from the inside of the valve cover, which would require a motor pull and taking off the valve cover. Which in dollars means about $350.

Please please tell me that he's full of crap. I thought you could replace it from the outside, especially after reading this thread.

Thanks!

-Jerimiah

Offline Gordon

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Re: Tach oil seal
« Reply #14 on: August 11, 2009, 05:49:55 PM »
My tach oil seal needs to be replaced. I've got a 78 CB750K. I was just at a shop getting some other stuff and asked the owner about it. He claims that the seal needs to be replaced from the inside of the valve cover, which would require a motor pull and taking off the valve cover. Which in dollars means about $350.

Please please tell me that he's full of crap. I thought you could replace it from the outside, especially after reading this thread.

Thanks!

-Jerimiah

I don't know if he's full of crap, but he's definitely wrong about this.  Tach oil seal replacement is a ten minute job.

Offline Johnie

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Re: Tach oil seal
« Reply #15 on: August 11, 2009, 05:52:05 PM »
My tach oil seal needs to be replaced. I've got a 78 CB750K. I was just at a shop getting some other stuff and asked the owner about it. He claims that the seal needs to be replaced from the inside of the valve cover, which would require a motor pull and taking off the valve cover. Which in dollars means about $350.

Please please tell me that he's full of crap. I thought you could replace it from the outside, especially after reading this thread.

Thanks!

-Jerimiah

I don't know if he's full of crap, but he's definitely wrong about this.  Tach oil seal replacement is a ten minute job.
He is wrong...take your seal out and show it to him when you get it done.  I would not be a dick about it, just let him know so he does not make the same mistake again.
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

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jerimiah797

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Re: Tach oil seal
« Reply #16 on: August 11, 2009, 05:55:18 PM »
Thanks guys. I won't be a dick about it, I just like to know what's what.

On my personal scale of wrong, $10  is 'oops'. $350 is 'full of crap'. :-)

-Jerimiah

Offline Johnie

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Re: Tach oil seal
« Reply #17 on: August 11, 2009, 05:57:00 PM »
Thanks guys. I won't be a dick about it, I just like to know what's what.

On my personal scale of wrong, $10  is 'oops'. $350 is 'full of crap'. :-)

-Jerimiah
My guess is he is a younger guy who has not done much work on the older bikes.  Too bad for him...
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

Oshkosh, WI  USA

jerimiah797

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Re: Tach oil seal
« Reply #18 on: August 11, 2009, 06:08:30 PM »
Actually he's an older guy. The shop has been around about 5 years and specialized in older japanese bikes. That's why I was so freaked out - he generally knows what he's talking about. :-)

http://www.southendmotorcycle.com/

-Jerimiah


Offline cb750fbomb

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Re: Tach oil seal
« Reply #19 on: August 11, 2009, 06:26:46 PM »
Late chiming in, but $350 is ridiculous. I don't know if it even took 10 minutes to do.
'77 CB750F2
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Offline Johnie

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Re: Tach oil seal
« Reply #20 on: August 11, 2009, 07:43:37 PM »
Do you think he was trying to scam you?
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

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Offline Popwood

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Re: Tach oil seal
« Reply #21 on: August 11, 2009, 07:49:14 PM »
+1 on that Gordon.
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Offline mystic_1

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Re: Tach oil seal
« Reply #22 on: August 11, 2009, 07:58:07 PM »
Tach oil seal replacement is a ten minute job.


Less, if you have the part in hand and don't stop too often to sip your beer.  :)

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Offline BobbyR

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Re: Tach oil seal
« Reply #23 on: August 11, 2009, 08:12:34 PM »
Actually he's an older guy. The shop has been around about 5 years and specialized in older japanese bikes. That's why I was so freaked out - he generally knows what he's talking about. :-)

http://www.southendmotorcycle.com/

-Jerimiah


He does know what he is talking about. It is about you contributing to his retirement fund.  ;D
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Offline Johnny5

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Re: Tach oil seal
« Reply #24 on: August 11, 2009, 08:12:55 PM »
Step 1. Pull engine (a few curse words because that engine is one heavy mutha)

Step 2. Take off valve cover (a lot of curse words because he didnt have an impact driver and stripped a few of those screws)

Step 3. Crap one's self when you realize the seal is on the outside of the valve cover (silence, except for the ooze sliding down the man's pants)



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1971 CB350
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2006 Harley Springer Classic