Topic: Still Have an oil leak.

[dzachary99]

OK, Last year I had an oil leak that surfaced itself on the cooling fins forward and to the outside of the number one spark plug. The fins (I think there's five) on the head that stick out father than the one's on the cylinder, above the head gasket. There's no eviedence of oil anywhere but on the fins. When I posted this problem It was suggested that the problem was the rubber disks under the cam holders. It got worse, so over the winter I pulled the motor and tore it down, the rubber disks looked good, but so did everything else. I changed every seal from the head gasket up. Tossed it back in the frame put on a pair of cycle x carbs and went-a-riden'.
   Last week I was washing it and there before my eyes was the SAME oil leak I just 'fixed'.  Is it common for these heads to crack? Thats the only other way for oil to get out. Anybody else ever seen this? I would take a picture but my Digital Camera broke too.

Thanks,
Doug

[frstmate]

Hi Doug
       I have the same problem on my 76 k6 oil leaks from the first 3 fins on the head on the left side. I also noticed that it continued to leak over night since the bike leans that way on th side stand.. If you find out the solution i would love to know before i go and tear it all down..

Thanks and good luck,
rick

[eldar]

If this oil is on the larger fins, is it on ALL the fins or just some? If it is just some, I would almost have to think there is an oil gallery there that may have a crack. Otherwise I would have to say that maybe the head bolts are not torqued enough or the valve adjustment covers.

[dzachary99]

Do these heads crack often or am I just one of the few lucky ones? Doesn't someone on here sell or rebuild heads?

Thanks for the response,
Doug

[Raul CB750K1]

If I'm not wrong, a slightly leaking head gasket was common on the CB750's, that even a gasket replacement wouldn't cure. As it's not a big leaking, I decided not worrying about and put a rolled paper handkerchief in the gasket. No matter how tight it was, I discovered that at the end the air would remove it. With a white pencil eraser cut to match I keep it in place in the front and the back. No more oil stains.

Raul -a.k.a. McGyver-

[Terry in Australia]

Those little seals that sit under your cam towers should have a thin coating of gasket sealant around their edges, or they will leak. One of my favourite books "Great bikes of the 70's", recommends a (very) light smear of gasket sealant on the head gasket and torqueing the head down to 19 foot pounds before the sealant sets, letting it sit overnight, then loosening off all the cylinder stud nuts and retorqueing them again, and they guaranteed that it wouldn't leak. I've done this religiously for many years now, and guess what? They don't leak!

Make sure your cylinder stud threads are clean and lightly oiled, or you may as well throw your torque wrench away. Raul, if your head gasket is leaking to the point where you can use it as a BB gun, it's time to get busy with the spanners mate, not even your mate MacGyver can fix that without pulling the engine out, ha ha! Cheers, Terry.  

[dzachary99]

Since we're talking about it, I did learn a thing or 5 about installing the head gasket and torquing the head which maybe useful to someone in the future. Be sure to note the lesser torque on the six BOLTS, not the studs. These are to be torqued DRY, NO OIL, per the Honda shop manual. The torque on these bolts cannot be increased or they will break, trust me! The stud's torque can be increased as someone else mentioned. Also it was recommended to me to apply 3 light coats of copper coat gasket sealer spray(Napa) to the stock head gasket and they won't leak. Torque it down, let it rest overnight then torque again. My head gasket is not leaking this leak is above it. Maybe this is odvious, but hang the gasket if you chose to use this spray, it is very, very, very sticky and will cause news paper to stick to it and could cause you to have throw a head gasket in the trash, I didn't do this, but I just thought I'd mention it since those gaskets are so expensive. Ha Ha.
Doug

[Vagelis]

Hey guys, I had the same problem on my 400/4 it drove me crazy. The rocker cover bolt above the #1 spark plug was the colprit. Where it screws in, it's drilled through, so if oil gets into the threads it runs out the bottom.
Hope I helped, Vagelis.

[dzachary99]

Vagelis,

Are you talking about the tappet covers? I can't see any oil except what's on the fins of the head just in front of the #1 spark plug?? I just can't figure out where it's coming from???


Thanks for you response.

doug

[Vagelis]

Goodmorning Doug,
I'm talking about the rocker cover threads. On my bike (400/4) they are drilled straight through.

Vagelis