Topic: Is this the source of my oil leak? (PICS!)

[Honda?]

 

1978 Cb750K
20k miles

Anyways my bike leaks oil from the #2 exhaust port area. It has always seemed to be from the HG but now that I have gotten the cams off it looks as tho the oil leak could be from one of the rubber plug things under the camshaft.

My questions are does this seem to be the source of my oil leak? And should I go any further? HG?

Here you can see pretty well what parts of the engine the oil has been leaking onto.

This is the rubber plug thing that I found under the camshaft and rocker arms.

another pic. (dont mine the spider )

[mkramer1121]

Could be, partsnmore has those at ~$12 each?  (I may be really over quoting them!).  Is that spark plug rather oil covered?

When we rebuilt my 750, we used some Yamabond to hold the pucks in place. 

[Honda?]

Yes when I pulled that particular spark plug it was covered in oil. I am hoping the HG doesn't need replacing.

I would still like more imput on this one. Because if I leave the HG and it still leaks I will need somebody to blame other than myself 

[Dusthawk]

I just hauled out the head I have sitting here waiting to be put on Rita, in where those discs go, it would be a safe assumption that that is the source of the leak.

On a side note, when I used to rebuild Chev parts and engines, I used a gasket sealer called Ultra-Copper for its heat resistance and sealing abilities. Would that also be something that would be beneficial for Rita to seal her up?

[Terry in Australia]

Yeah mate, that's the source of your leak, you can buy those "pucks" from Z1 Enterprises for a couple of bucks each, and you don't need to go any further with your investigation. Clean up the holes and smear a little Threebond 1104 around the edges, and it'll be fine. Just make sure you don't get any sealant into the oil jets (also under the cam towers) or you'll cook your top end.

Jeff, there was discussion a couple of years ago on the "Greenspun" forum regarding the best sealant for these engines and the big concern was the dangers of "balls" of silicon getting into the oil system and blocking oil jets in the head, and even though Threebond contains a small amount of silicon, it was considered by the majority to be the favored sealant. The other good thing is that as it's a gray color, it's not noticeable on our silver cases. (Of course if your engine is black...............) Cheers, Terry.  
   

[Dusthawk]

I can understand where some might be conserned with the balls of it getting into the engine, but I learned a long time ago that with UltraCopper an Ultra thin shmear of it works best on most gaskets, and any that might squeeze out can easily be cleaned with a paper towel. It is just what I have the most experience with is why I ask.

[RRRToolSolutions]

Yes, that would leak for sure.

Guys, I suggest nothing but the Honda "sealing rubbers". I went with aftermarket the first time around --yea the 2nd time and the third time I used Honda exclusively on everything but the head gasket. Those aftermarket ba$tards leaked. Clean the sealing surface with acetone or lacqer thinner on a towel then put a trace of 1104/Hondabond to the edge of the recess where these sit. I've never had a leak since.

One more tip - if you remove those little 6mm studs holding the cam blocks in-place (shown in your photo), be sure to apply Blue Loctite to the threads. Even though tight, those will allow oil to seep down the threads and onto your spark plug base as they are drilled completely through the head (learned the hard way).

Here's that picture that is supposed to save me a 1,000 words -

Gordon

[Kevin D]

I found'em for $2.33 each at Service Honda.

Please don't deplete their stock, I'm gonna need a batch of them myself!

[Tim.]

I've got a few of those left over from my 550 days.  I'll double check the part number but I'm sure they're the same ones.  Probably have 6 or so in the Honda packaging.

Anyone need 'em?

[Kevin D]

Anyone need 'em?

Go for 'em, ?. I'm a month away from making my parts order.


Hey, 96 tears is a great song, are you the same ? :

http://www.myspace.com/questionmarkandthemysterians


 

[Terry in Australia]

I haven't tried the rubber seals in my CycleX "Emgo" gasket set yet, but the seals I bought from Z1 are OEM, as was the new camchain adjuster etc. Cheers, Terry.