Author Topic: 69-76 vs 77-78 valve keepers  (Read 1170 times)

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Offline drumstyx

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69-76 vs 77-78 valve keepers
« on: March 28, 2016, 10:13:38 PM »
As usual, I'm hard at work trying to figure out what exactly I have to buy (how poor I will be) to rebuild my '78 750K.

One thing that's coming up is, what's the deal with the valve keepers?

Assuming I can get 77-78 valves, which seem to be rather hard to come by, what's the harm in having the later style keepers? It'd save me probably a $150+ in new keepers and spring retainers for the conversion...

Offline 70CB750

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Re: 69-76 vs 77-78 valve keepers
« Reply #1 on: March 29, 2016, 04:02:16 AM »
I was not brave enough to reuse the late style keepers, got mine from CycleX.

But I gave some of my old valves to Davidov and he used them in his build and all seems to be ok.

My take is that in extreme situations, the late style keepers could fail, but I still was not brave enough to use them.

I assume you have this, right?

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Offline madmtnmotors

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Re: 69-76 vs 77-78 valve keepers
« Reply #2 on: March 29, 2016, 04:29:29 AM »
The biggest problem was the keepers pulling through the stamped steel spring retainer cap under extreme conditions (high rpm). The later "F" models were more susceptible, but the K8 could have this happen as well. I stuck with the later model keepers, but opted for the stronger (Kibblewhite) valve spring retainer caps available from CycleX.
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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: 69-76 vs 77-78 valve keepers
« Reply #3 on: March 29, 2016, 11:51:30 AM »
You SHOULD be able to use any of the earlier valves as long as you ALSO use the earlier keepers. Not sure if this might be a plausible solution for you? You just can not use 77/78 F valves.

Whatever, use the stronger 78 valve springs which should work fine with the original retainer. I used my retainers with after-market S & W springs from Yoshimura (812 and big lift cam) and they went through the redline OFTEN and held up. 
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline oldskullero

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Re: 69-76 vs 77-78 valve keepers
« Reply #4 on: March 30, 2016, 03:32:45 PM »
I was not brave enough to reuse the late style keepers, got mine from CycleX.

But I gave some of my old valves to Davidov and he used them in his build and all seems to be ok.

My take is that in extreme situations, the late style keepers could fail, but I still was not brave enough to use them.

I assume you have this, right?



May i know from what book is this 70cb750?

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Offline Jerry Rxman Griffin aka MuthaF'er

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Re: 69-76 vs 77-78 valve keepers
« Reply #5 on: March 30, 2016, 06:32:43 PM »
Yeah, that's the best valve train reference I have seen.
As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)