Immediate and significant leaking from tach cover

305explr · Post by **305explr** » Wed Jul 10, 2013 3:02 pm

Hi all,

Long time no post, but now I'm back into it.

After rebuilding my '64 305 motor, I see that it leaks from (I believe) behind the tach cover.

Here are the particulars:

-I used a 16 x 28 x 7 seal (Honda #91204-259-000) and a new gasket.
-I did not use any gasket sealant.
-my tach cable housing is cracked and its o-ring may have been damaged when I installed it.

I run the bike and it leaks -- too much to be acceptable.

I have two questions:
1.) Would a cracked cable housing and a torn o-ring allow that much oil to migrate up the worm gear? We're talking oil-on-the-pant-leg amounts.
2.) Has anyone else had this problem?

Here's a picture in case what I'm saying isn't clear to all. Note the oil on the edge of the gasket surface (left) and along the cooling fins. I do not believe this is spark plug related.

Additional photos available upon request. All help appreciated, as always.

48lesco · Post by **48lesco** » Wed Jul 10, 2013 3:44 pm

Yes - they can leak quite a bit of hot oil from that location. If you have a cracked housing and a torn o-ring, I would fix those first and report back...
-48

jensey · Post by **jensey** » Wed Jul 10, 2013 3:49 pm

Hi,

Are the camshafts installed correctly ?
Do the surfaces of the housing and the head really meet ?

Replace the cracking housing btw, how did it crack ? By mounting it onto the head ?

Jensen

305explr · Post by **305explr** » Wed Jul 10, 2013 6:08 pm

Thanks guys.

48lesco: I'd planned on removing the cable and capping the tach cable threads. That will remove the housing and the o-ring from the equation. I'll do that then report back.

And Jensey: When I say "housing" I'm talking about the vinyl cover surrounding the old/original cable.

I think maybe you're thinking about the gasket. The gasket is fine, but your point is valid. I will try to slip a feeler gauge in to see if there's a gap between the tach cover and the end of the head.

Maybe the tach cover is bottoming out against the bearing shell before the gasket can truly seal? This is something I need to measure w a set of calipers.

I'll be in touch.

jensey · Post by **jensey** » Thu Jul 11, 2013 1:02 am

Hi,

Yes, I was thinking about the gasket, because the surface of the head looks almost "too" clean. Sorry, I misunderstood your question.

Jensen