Author Topic: CB750F2 head gasket  (Read 2922 times)

Offline Spitfire

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CB750F2 head gasket
« on: September 16, 2014, 03:37:14 PM »
Well after working on the grandsons bike and getting in some riding time on the F1 I decided to do something about the various lumps of metal dotted around the garage, these make up a 1977 CB750F2 that I bought in the late 1980's to give me something to play with. The bike had sat out in the rain with the plugs out for a couple of years so I rebuilt the top end with new pistons, rings valves etc, stripped the whole bike and resprayed it all red, then in 1994 came the chance to work overseas so off I went for the next 10 years. When we came back (2004) it was time to overhaul the house, this took a couple of years, then another couple of years to rebuild my CB750F1, but I never got around to finishing the F2, I started painting all the parts black and took down the top end of the engine to check it out.
So now I have started to rummage through the parts that I bought for the rebuild way back when, I have found a new gasket set from David Silvers (KP) which I bought for the F2, and the remnants of an NP set which includes a head gasket as I always use genuine Honda head gaskets, I also found another head gasket sandwiched between two pieces of grease proof paper with no markings at all, this one has the small stud holes in all locations so I think it is an earlier one.
The question is as the genuine F2 gaskets seem to be extinct which one should I use the KP one or the NP one as I have no experience of either, trawling through other posts on the subject seem to say keep away from the Athena one.

Cheers

Dennis
« Last Edit: September 16, 2014, 03:45:07 PM by Spitfire »
1976 CB750F

1977 CB750F2 In bits

1964 BSA A65R In bits

Offline Bryanj

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Re: CB750F2 head gasket
« Reply #1 on: September 16, 2014, 05:38:12 PM »
Use the origanal and make sure all the oilways are supper clean on the i am only doing this once principle

Offline Spitfire

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Re: CB750F2 head gasket
« Reply #2 on: September 17, 2014, 11:16:25 AM »
I'd love to use an original gasket Bryan but they are extinct.

Cheers

Dennis
1976 CB750F

1977 CB750F2 In bits

1964 BSA A65R In bits

Offline AshimotoK0

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Re: CB750F2 head gasket
« Reply #3 on: September 17, 2014, 11:26:07 AM »
I only have experience of using NP gaskets on CB250 / 350 K  & CB400/4's but must say I never had any problems with them.

Wonder what DSS uses. I will ask him.

What's that lockup of yours looking like these days BTW Bryan. I remember you sent me  a photo of it years ago and it was stacked to the gunnels!  ;D

Cheers ... Ash
« Last Edit: September 17, 2014, 11:28:52 AM by AshimotoK0 »
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Offline Spitfire

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Re: CB750F2 head gasket
« Reply #4 on: September 17, 2014, 11:37:02 AM »
Thanks Ash, I have just checked out CMSNL and they have originals but for 124 euros, so I think I will go for the NP one !

Cheers

Den
1976 CB750F

1977 CB750F2 In bits

1964 BSA A65R In bits

Offline UK Pete

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Re: CB750F2 head gasket
« Reply #5 on: September 17, 2014, 02:02:12 PM »
I paid £50 for a nos f2 head gasket a couple of years back so i had a spare, i can have a look out for it if you want , i would be looking to get my £50 back though
pete

Offline Spitfire

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Re: CB750F2 head gasket
« Reply #6 on: September 17, 2014, 02:19:59 PM »
Sounds great to me, if it is OK with you, I'll PM my address and details to you, done.

Cheers

Dennis
« Last Edit: September 17, 2014, 02:23:36 PM by Spitfire »
1976 CB750F

1977 CB750F2 In bits

1964 BSA A65R In bits

Offline UK Pete

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Re: CB750F2 head gasket
« Reply #7 on: September 17, 2014, 05:51:10 PM »
Den , i will have a look through my Aladdins cave, i am 90% sure i have one , but no idea where i stashed it , i am away motorhoming friday so i wont have the chance to post it till next week sometime ,
pete

Offline Spitfire

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Re: CB750F2 head gasket
« Reply #8 on: September 17, 2014, 07:11:17 PM »
Thanks Pete, there's no hurry, as usual I have had to order all the O rings from David Silver, and I want to give the head and barrels a good clean, they have been sitting on my bench for 5 years so I want to give them a good going over.

Cheers

Den
1976 CB750F

1977 CB750F2 In bits

1964 BSA A65R In bits

Offline Bryanj

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Re: CB750F2 head gasket
« Reply #9 on: September 18, 2014, 09:31:50 AM »
Sorry mate, these 15 hour shifts are getting to me! I read it as you had a New honda one already. i used both NP and Noboru many times with never a failure

bike-pusher

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Re: CB750F2 head gasket
« Reply #10 on: September 18, 2014, 09:34:39 AM »
As an F2 owner, I'm curious - what's the difference between an F2 and an earlier head gasket? Tougher one on the F2 is my guess, but I'd like to know.

Offline Spitfire

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Re: CB750F2 head gasket
« Reply #11 on: September 18, 2014, 09:46:22 AM »
Sorry mate, these 15 hour shifts are getting to me! I read it as you had a New honda one already. i used both NP and Noboru many times with never a failure
No worries Bryan, I worked shifts for 30 years so I know where you are coming from, good to know that the NP gaskets are good.

Cheers

Den
1976 CB750F

1977 CB750F2 In bits

1964 BSA A65R In bits

Offline UK Pete

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Re: CB750F2 head gasket
« Reply #12 on: September 18, 2014, 01:32:12 PM »
Honda f2 gaskets have the oval shaped fire rings to suit the combustion chamber, also they have factory sealant round cam tunnel and the oil passage holes, they are much heavier and better made than aftermarket

bike-pusher

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Re: CB750F2 head gasket
« Reply #13 on: September 18, 2014, 07:35:43 PM »
Hm.  So fitting a 'standard' head gasket is asking for trouble?

Offline UK Pete

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Re: CB750F2 head gasket
« Reply #14 on: September 18, 2014, 10:55:10 PM »
 can be trouble with cheaper gaskets , it is wise to fit Original honda if possible but they are no longer available, so a good quality gasket has to do in most cases
pete

 

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