Author Topic: Went and bought a head. Now what?  (Read 2286 times)

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Offline Pinhead

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Went and bought a head. Now what?
« on: September 10, 2008, 06:26:11 pm »
I bought a used head off ebay for my '79 CB650. I'm going to rebuild it and keep my bike's downtime to a minimum. HERE's the auction. It came with (as far as I can tell) everything except for the rockers.

For a head rebuild, what all do I need? I'm going to assume all that would need to be replaced would be valve guides and seals? That's assuming, of course, none of the valves are bent and nothing is excessively worn. I'm going to do some port work and possibly plane it for a tad higher compression if I can't find a thinner head gasket.

Along those lines, where can I get a complete top-end gasket set for my 650? It will have to include all o-rings. This will be my first experience inside my 650. Any help would be appreciated.
Doug

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Offline mystic_1

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Re: Went and bought a head. Now what?
« Reply #1 on: September 11, 2008, 04:53:46 am »
If you replace the valve guides, you'll need to have a full valve job done.  Just replace the seals unless the guides are actually shot.

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martino1972

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Re: Went and bought a head. Now what?
« Reply #2 on: September 11, 2008, 06:12:29 am »
with only 22k on the head ,i would check if valves are leaking,if head is straith ,but i dont think you have to go "in debt" into that head,should be barely broken in..

Offline goon 1492

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Re: Went and bought a head. Now what?
« Reply #3 on: September 11, 2008, 06:51:26 am »
Hey pinhead where in KC are Ya? I'm up north by worlds of fun, just off I-35 and north brighton behind the mini putt golf course.
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Offline CBJoe

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Re: Went and bought a head. Now what?
« Reply #4 on: September 11, 2008, 08:27:58 am »
I believe that http://www.servicehonda.com/ has the complete OEM top end gasket set (gasket set A) for a good price.

Cheers...Joe
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Offline Pinhead

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Re: Went and bought a head. Now what?
« Reply #5 on: September 11, 2008, 10:56:24 am »
Hey pinhead where in KC are Ya? I'm up north by worlds of fun, just off I-35 and north brighton behind the mini putt golf course.

I live in Shawnee, around K-7 and Johnson Drive.

with only 22k on the head ,i would check if valves are leaking,if head is straight ,but i don't think you have to go "in debt" into that head,should be barely broken in..

I was thinking the same thing, will just do the port and valve work as described HERE.

I believe that http://www.servicehonda.com/ has the complete OEM top end gasket set (gasket set A) for a good price.

Cheers...Joe

Thanks! I'll definitely look into it.
Doug

Click --> Cheap Regulator/Rectifier for any of Honda's 3-phase charging systems (all SOHC4's).

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By the way, I'm going for the tinfoil pants...so they can't read my private thoughts.
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Offline Pinhead

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Re: Went and bought a head. Now what?
« Reply #6 on: September 19, 2008, 08:27:45 pm »
I can't find a "gasket set" on Service Honda's website... I went to the Remote Desktop to look up PN's and found the individual parts but no complete set. Am I looking in the wrong place?

Also, SH shows 3 different head gaskets for my bike. What's the difference? Thickness maybe??

Also, are there any specific tools that I need to get before I take the engine apart? All I have is basic hand tools.
Doug

Click --> Cheap Regulator/Rectifier for any of Honda's 3-phase charging systems (all SOHC4's).

GM HEI Ignition Conversion

Quote from: TwoTired
By the way, I'm going for the tinfoil pants...so they can't read my private thoughts.
:D

Offline kslrr

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Re: Went and bought a head. Now what?
« Reply #7 on: September 19, 2008, 09:43:21 pm »
It looks like the rockers are inplace in the cam/valve cover.  All you need are the gaskets and tapet adjustment covers and you are good to go.  Do check the condition of the threads that the tapet adjustment covers bolt into.  I had to Heli-coil all of them on my '79.
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Then 1972 CL175
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Offline bryanj

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Re: Went and bought a head. Now what?
« Reply #8 on: September 20, 2008, 01:34:22 am »
Look up the head gasket and take note of the middle number, then put 06110 as the first number or 06111 one is a top set the other is a bottom set, price should tell you which is which. you will have to experiment with the last number start with 000 then 010 then 020 etc till you find one that works
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Offline speedy gonzalais

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Re: Went and bought a head. Now what?
« Reply #9 on: September 20, 2008, 05:35:28 am »
I can't find a "gasket set" on Service Honda's website... I went to the Remote Desktop to look up PN's and found the individual parts but no complete set. Am I looking in the wrong place?

Also, SH shows 3 different head gaskets for my bike. What's the difference? Thickness maybe??

Also, are there any specific tools that I need to get before I take the engine apart? All I have is basic hand tools.

A valve spring compressor would make life alot easier.
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Offline CBJoe

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Re: Went and bought a head. Now what?
« Reply #10 on: September 20, 2008, 07:19:26 am »

I guess that Service Honda doesn't show a A and B set for the '79 CB650.  It does for 80-82 though.  I thought that the '79 and '80 were the same with regards to gaskets. 

Can someone chime in on what would be different gasket wise between teh '79 and '80??

Gasket Kit A - PN 061A1-426-T30  on Service Honda. 

Cheers...Joe
'07 Bonneville Black
'15 Moto Guzzi California 1400
CB750K2 Hot Rod Revival http://forums.sohc4.net/index.php/topic,171693.0.html
'65 CB77
'66 CM91 (C90'ish)

Offline Soos

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Re: Went and bought a head. Now what?
« Reply #11 on: September 20, 2008, 08:18:46 am »
Dunno....
The gasket kit I bought was for a '80 to '82 cb650.
didn't mention '79cb650... but every gasket I installed was fine.
No leaks (yet?)...

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(61mm)652cc 1979 cb650

Offline Pinhead

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Re: Went and bought a head. Now what?
« Reply #12 on: September 20, 2008, 10:58:45 am »

I guess that Service Honda doesn't show a A and B set for the '79 CB650.  It does for 80-82 though.  I thought that the '79 and '80 were the same with regards to gaskets. 

Can someone chime in on what would be different gasket wise between teh '79 and '80??

Gasket Kit A - PN 061A1-426-T30  on Service Honda. 

Cheers...Joe


Gasket Kit A 061A1-426-T30 contains everything I'll need, right, O-rings and all?

Edit: What I'd really like to do is install a thinner head gasket to tighten the squish up a bit. The only way I could do that, however, is to order a custom gasket from Cometic and the o-rings from Honda unless there's a cheaper combination. Any suggestions? Or maybe it'd be better to shave the jugs to get the squish I want...
« Last Edit: September 20, 2008, 11:10:07 am by Pinhead »
Doug

Click --> Cheap Regulator/Rectifier for any of Honda's 3-phase charging systems (all SOHC4's).

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Quote from: TwoTired
By the way, I'm going for the tinfoil pants...so they can't read my private thoughts.
:D

Offline WFO

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Re: Went and bought a head. Now what?
« Reply #13 on: September 20, 2008, 11:23:43 am »
82 cb650 sc nighthawk - 78 kz 650 b

Offline Pinhead

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Re: Went and bought a head. Now what?
« Reply #14 on: September 20, 2008, 11:26:44 am »
Another question... If I end up removing the jugs to get them planed/shaved, I'm assuming I'll need a new gasket set for the bottom as well. I guess here's my main question: If I remove the head and jugs, what do I need to order to get it sealed back up? Would anyone happen to have a PN list for what they've already done/used for a basic rebuild?
Doug

Click --> Cheap Regulator/Rectifier for any of Honda's 3-phase charging systems (all SOHC4's).

GM HEI Ignition Conversion

Quote from: TwoTired
By the way, I'm going for the tinfoil pants...so they can't read my private thoughts.
:D

Offline bryanj

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Re: Went and bought a head. Now what?
« Reply #15 on: September 20, 2008, 02:54:52 pm »
Cylinder base gasket is in the top end set as Honda say if you loosen the head you need to change it due to removal of clamping forces
Semi Geriatric ex-Honda mechanic and MOT tester (UK version of annual inspection). Garage full of "projects" mostly 500/4 from pre 73 (no road tax in UK).

Remember "Its always in the last place you look" COURSE IT IS YOU STOP LOOKIN THEN!

Offline Pinhead

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Re: Went and bought a head. Now what?
« Reply #16 on: October 06, 2008, 11:01:40 am »
« Last Edit: October 06, 2008, 10:16:45 pm by Pinhead »
Doug

Click --> Cheap Regulator/Rectifier for any of Honda's 3-phase charging systems (all SOHC4's).

GM HEI Ignition Conversion

Quote from: TwoTired
By the way, I'm going for the tinfoil pants...so they can't read my private thoughts.
:D