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Head Gasket Leak CA72.

deafanddiabetic
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Joined: Thu Jun 19, 2014 6:04 pm
Location: Nebraska

Post by deafanddiabetic » Thu Oct 30, 2014 8:22 pm

Hey G-Man, wanted to let you and everyone else know how easy it is to spend 5 months making beginner mistakes.

All this time I couldn't figure out my compression issues and leaks at the head gasket, I finally took it apart one last time to examine and had my boss at the motorcycle shop take a look at it. Lo and behold, I never took off the old head gasket, I just added another one to it. Of COURSE it leaked between the two gaskets.

So, things should be hunky dory from here on out engine-wise with only one gasket in place.

Everybody, check for the simplest things first before you have heads machined, buy new washers, buy a new torque wrench, take the engine apart 6 times.

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G-Man
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Post by G-Man » Fri Oct 31, 2014 1:51 am

D&D

So glad you got things sorted out. And thank you for feeding back. So often folks forget to report back what ultimately fixed their problems. You get to learn and then we all learn, That's the great thing about sharing on a Forum.

Please continue posting about your adventure with your bike. We like to hear good news as much as we like to help solve problems.

Good luck for a leak-free future.....

G
'60 C77 '60 C72 '62 C72 Dream '63 CL72
'61 CB72 '64 CB77 '65 CB160
'66 Matchless 350 '67 CL77
'67 S90 '77 CB400F

deafanddiabetic
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Posts: 258
Joined: Thu Jun 19, 2014 6:04 pm
Location: Nebraska

Post by deafanddiabetic » Wed Dec 03, 2014 5:22 pm

It's been about a month, I've been really busy with a new job and working on a BMW /2 project so the Dream has been in the back of the garage.

I did put a new (single) head gasket on and put everything back together including new O-rings on the knock pins with the new steel washers in a 4x4 pattern and torqued the acorns to hell.

It still leaks from the head gasket.

I'm going to have it machined this winter, I don't think there's anything else that I can do?

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Waveblaster
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Post by Waveblaster » Wed Dec 03, 2014 8:24 pm

D&D

Can you post a pic so the folks here can help. Oil leaks can sometimes not be originating from where you first think.

It seems strange that it is still leaking.

Are the O rings the correct ones? The after market gasket set I use they are green.

Are the locating pins the correct ones? Can you use a set of calipers to measure the length of pins and depth of the associated holes in head and barrels.

Have you checked the exposed length of the head bolts and depth of the acorn in case they are not home in the top engine case.

Correct washers steel and copper fitted to top cover , thickness.

correct gaskets above and below oil deflector plate to top of head.

Any material from the old gasket still stuck to the head or barrels.

deafanddiabetic
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Posts: 258
Joined: Thu Jun 19, 2014 6:04 pm
Location: Nebraska

Post by deafanddiabetic » Wed Dec 03, 2014 9:35 pm

Thanks for the response Waveblaster, I'll try to pull the engine apart this weekend and take some pictures.

I know very definitively that's leaking from the head gasket, as I'd ruled out cam cover gaskets previously. I used brake cleaner then put talcum powder around gasket sections and it's coming from left side head gasket about 2 inches back from the exhaust port.

I bought an NOS set of gaskets from a friend at a Honda dealership, it came with two green O-Rings. I did clean out the knock pin holes before putting the O-Rings on but did not specifically measure them although I found them to be "fully seated" and visually the same amount of height from the head.

The gaskets that came with for the oil deflector came with two pieces, one with the holes that aim forwards for oil passage and then a normal gasket below it that fits to the top cover. There was no gasket material left after shaving, brake cleaner and then having the head machined flat by a guy in town. All surfaces seemed as clean as I could get them.

I don't know what measurements the copper and steel washers are supposed to be, I ordered them based on part numbers found in these forums. But I will take some measurements and post my results here in a few days.

Thanks for the help, it's definitely frustrating.

deafanddiabetic
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Posts: 258
Joined: Thu Jun 19, 2014 6:04 pm
Location: Nebraska

Post by deafanddiabetic » Sun Dec 07, 2014 6:35 pm

Okay, here's a big picture dump and explanations.

So, I accidentally crushed one of my knock pins so it looks like I'll be hunting one of those down. Damn it.

But, there's measurements here for the top cover gasket (which is like two gaskets formed into one), measurement of the knock pins coming out of the head, measurement of the head gasket is here as well and seems fairly small and measurements of the knock pin itself.

I also found that my cylinder studs, that the inner two are taller than the outer two. Not sure if that's supposed to be the case.

There's also some gasket gunk that I need to clean off of both surfaces, that may help as well.

Let me know if this is helpful?
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deafanddiabetic
honda305.com Member
Posts: 258
Joined: Thu Jun 19, 2014 6:04 pm
Location: Nebraska

Post by deafanddiabetic » Sun Dec 07, 2014 6:36 pm

And second page.
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