Author Topic: NOS Engine Gaskets....Coppercoat, Hondabond, or Dry?  (Read 1252 times)

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Offline 574hondarider

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NOS Engine Gaskets....Coppercoat, Hondabond, or Dry?
« on: September 10, 2019, 05:59:35 AM »
When doing a top end, what is the best method for installing NOS Honda engine gaskets......use coppercoat, hondabond in select areas, or just get everything clean and dry?  Inquiring minds want to know!!

Thanks :-)

Offline markreimer

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Re: NOS Engine Gaskets....Coppercoat, Hondabond, or Dry?
« Reply #1 on: September 10, 2019, 06:10:03 AM »
I always did dry. Except the 350F, I used coppercoat on the head gasket. None of them leaked.

Used hondabond on the valve covers


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Offline 1976cb750f836

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Re: NOS Engine Gaskets....Coppercoat, Hondabond, or Dry?
« Reply #2 on: September 10, 2019, 06:35:24 AM »
I use copercoat on Everything, car engine head gaskets, bikes, lawn tractor, all head gaskets, even the ones that say to go dry. Never had a blown gasket. I always make sure everything is flat. Either machine shop, or sandpaper on glass, or file.

Offline maxheadflow

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Re: NOS Engine Gaskets....Coppercoat, Hondabond, or Dry?
« Reply #3 on: September 10, 2019, 08:33:54 AM »
Back in the day, I used grease on all the gaskets except the head gasket.  HG was usually dry but maybe a little Gaskasinch on the oil passage holes.

Offline ekpent

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Re: NOS Engine Gaskets....Coppercoat, Hondabond, or Dry?
« Reply #4 on: September 10, 2019, 08:53:20 AM »
 You never mentioned the size of the engine but if it was a real genuine Honda head gasket I would go dry as they had a nice coating on them that seemed to help seal. Ask anyone who has had to scrape off the residue from an old one on a 750. I like to put a little sealer on the cover side of case cover gaskets to help keep them in place and hopefully in the future have the gasket come off with the cover if I need to remove it.
« Last Edit: September 10, 2019, 11:46:58 AM by ekpent »

Offline 574hondarider

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Re: NOS Engine Gaskets....Coppercoat, Hondabond, or Dry?
« Reply #5 on: September 10, 2019, 09:59:08 AM »
You never mentioned the size of the engine but if it was a real genuine Honda head gasket I would go dry as they had a nice coating on them that seemed to help seal. Ask anyone who has had to scrape off the residue from an old one. I like to put a little sealer on the cover side of case cover gaskets to help keep them in place and hopefully in the future have the gasket come off with the cover if I need to remove it.

It's for a 350f.  Thanks for all the replies, very good information here!!

Offline HondaMan

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Re: NOS Engine Gaskets....Coppercoat, Hondabond, or Dry?
« Reply #6 on: September 10, 2019, 06:31:12 PM »
I'd STRONGLY suggest milling the cylinder deck at least 0.010" (0.020" better) and then adding a little bit of Permatex#2 around the oil feeder holes' seals on the head gasket.
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Offline 574hondarider

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Re: NOS Engine Gaskets....Coppercoat, Hondabond, or Dry?
« Reply #7 on: September 11, 2019, 05:24:21 AM »
I'd STRONGLY suggest milling the cylinder deck at least 0.010" (0.020" better) and then adding a little bit of Permatex#2 around the oil feeder holes' seals on the head gasket.

I really appreciate your knowledge and suggestion.  I'm pretty new to the whole scene.  Is this something I can take to someone to mill as I have no experience milling?
« Last Edit: September 11, 2019, 05:42:42 AM by 574hondarider »

Offline PeWe

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Re: NOS Engine Gaskets....Coppercoat, Hondabond, or Dry?
« Reply #8 on: September 11, 2019, 06:30:38 AM »
Head gasket dry!
I used Permatex copper spray once and what a leak within a few km!

Both my bikes are now really dry. CB750.
I guess that other models might have weaknesses that must have a sealer added.

K6 (1005cc) with RCS base gasket and MLS head gasket. Both mounted dry. No leak at all after around 9000 km. I had some overpressure causing oil weep around oil filter holder. Added an additional breather in clutch cover solved it. 

My K2 bone dry. 736cc, std base gasket and cheap std head gasket from kit as DSS sell. No leaks at all.
Only extra sealer used under rubber coins under the cam holders. (Permatex aviation no3 as used on both cases)

There are other places where oil can leak.
« Last Edit: September 11, 2019, 06:35:32 AM by PeWe »
CB750 K6-76  970cc (Earlier 1005cc JMR Billet block on the shelf waiting for a comeback)
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Updates of the CB750 K6 -1976
http://forums.sohc4.net/index.php/topic,180468.msg2092136.html#msg2092136
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http://forums.sohc4.net/index.php/topic,49438.msg1863571.html#msg1863571
CB750 K2 -1975  build thread
http://forums.sohc4.net/index.php/topic,168243.msg1948381.html#msg1948381
K2 engine build thread. For a complete CB750 -75
http://forums.sohc4.net/index.php/topic,180088.msg2088008.html#msg2088008
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http://forums.sohc4.net/index.php/topic,179479.msg2104967.html#msg2104967

Offline 1976cb750f836

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Re: NOS Engine Gaskets....Coppercoat, Hondabond, or Dry?
« Reply #9 on: September 14, 2019, 06:03:38 AM »
Any automotive mach shop should be able to machine cylinder deck, and while your their, have them level the head!

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: NOS Engine Gaskets....Coppercoat, Hondabond, or Dry?
« Reply #10 on: September 14, 2019, 09:29:26 AM »
The only reason I'd use any sealer on any gasket on the Honda is to simply tack it in place. It is not necessary unless there is a leak due to an uneven surface. 
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)