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Author Topic: 77K head  (Read 1169 times)

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Offline katman

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77K head
« on: January 02, 2013, 05:36:12 AM »
Hey everyone,
Will any other year head fit my 77K if I can,t find an intake spigot. And did the 750 automatics use the same head.
Thanks
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Offline MRieck

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Re: 77K head
« Reply #1 on: January 02, 2013, 05:51:12 AM »
Any head except an F2
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Offline 754

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Re: 77K head
« Reply #2 on: January 02, 2013, 07:20:52 AM »
 A head has smaller intakes i believe, carbs are smaller.
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: 77K head
« Reply #3 on: January 02, 2013, 06:42:40 PM »
The 77 K head is a -392 head. Originally found on the 75/76 F model then used on the 77/78 K. You'll notice a '392' on the top fin intake side by #3. If you find a 'complete' 78 K head it will have stronger springs, different keepers and valves will be different only due to the change in keepers. If it's bare it is identical. Just don't be tempted by the F2/F3 as Mike says. Too much work to make it work.
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As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline raymond10078

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Re: 77K head
« Reply #4 on: January 02, 2013, 07:08:27 PM »
Per the microfiche, the A head is the same, too.
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Offline katman

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Re: 77K head
« Reply #5 on: January 02, 2013, 07:28:24 PM »
Thanks guys, what does the F2 and F3 mean
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Offline katman

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Re: 77K head
« Reply #6 on: January 02, 2013, 07:37:50 PM »
So I got my eye on a nice 76 head. This will work on my 77 alright?
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: 77K head
« Reply #7 on: January 02, 2013, 07:41:59 PM »
Quote from: katman on January 02, 2013, 07:28:24 PM
Thanks guys, what does the F2 and F3 mean

Last 2 years of the 750 F (in the States). This was the big valve engine. Leave it at that for now to keep things simple for what you are doing here.
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As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: 77K head
« Reply #8 on: January 02, 2013, 07:44:37 PM »
Quote from: katman on January 02, 2013, 07:37:50 PM
So I got my eye on a nice 76 head. This will work on my 77 alright?

Yes it will but which '76 engine? K, F, or A. I'm trying to be exact/precise however so be specific for a specific answer.
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As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline katman

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Re: 77K head
« Reply #9 on: January 03, 2013, 05:39:44 AM »
Okay, I am looking at a 76 K head and a 78 head that has the 392 on it as mentioned above, It is bare so I think I can
use my valves. I am leaning toward it.
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: 77K head
« Reply #10 on: January 03, 2013, 11:56:33 AM »
The 76 K will work but the combustion chamber design is different as you'll notice. The 78 K 392 head is EXACT and yes, you can use your valves. Now if you could get the valve springs from the 78 I'd use them as they are stiffer and less likely to float as mine did when I missed my 1 to 2 shift and broke a valve which destroyed my engine. I think if someone cc'd both heads they might find that the 392 head's combustion chamber design contributes to the increased compression ratio too.
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As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)
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