Author Topic: 78 CB750 K Valve Cover Removal  (Read 914 times)

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Offline mrmach5

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78 CB750 K Valve Cover Removal
« on: December 09, 2019, 07:00:57 AM »
I've got my 78 CB 750K on the lift for some maintenance, carbs, valve adjustment, tune , etc. While there thought I remove the valve cover and send it off to have it chromed. I'm having problems removing it from the bike. Will it come off with the engine intact. Seems like no matter how I move it around its hitting something and can't get it to clear. Am I missing something?
Thanks

Offline my name is nobody

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Re: 78 CB750 K Valve Cover Removal
« Reply #1 on: December 09, 2019, 07:12:21 AM »
If its like the earlier 750, it won't come off without removing the engine. ou might be
able to remove the engine mounting bolts to lower it in the frame, but being a k5 owner, I don't know about the k8. Engine out unless you have installed a frame kit that requires cutting
the upper frame tubes to install.

Offline kerryb

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Re: 78 CB750 K Valve Cover Removal
« Reply #2 on: December 09, 2019, 07:42:21 AM »
It's true, the engine of a k8 must come out to remove the valve cover.  You might want to investigate some of the methods used before deciding to proceed.  Like many here l work alone so I prefer the c-hook method, others prefer to slide the engine out hung from a rail extending through the frame.  There are many ways to proceed based on your particular situation.  Do you have strong friends?, maybe have an engine-handling party!
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Offline ekpent

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Re: 78 CB750 K Valve Cover Removal
« Reply #3 on: December 09, 2019, 08:32:59 AM »
 One of the little joys of owning a SOHC CB750  :D
« Last Edit: December 09, 2019, 10:01:22 AM by ekpent »

Offline mrmach5

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Re: 78 CB750 K Valve Cover Removal
« Reply #4 on: December 09, 2019, 09:26:19 AM »
Well, looks like the chrome idea was a good one , however not pulling the motor just for some shine,,,,,, so going Au Natural !
I have an 80 750F DOHC and no problem getting the cover off on that one,,,,, just a PITA doing the valve adjustment.
Thanks for the info!

Online Don R

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Re: 78 CB750 K Valve Cover Removal
« Reply #5 on: December 09, 2019, 10:10:54 AM »
 Maybe it's just me but I have several old chrome valve covers, most of them look awful and one of the nice ones even with my best efforts, won't seal. I doubt many of the chromers in the day took pains ($$)  to get it right but I've never had much luck with chrome on aluminum. (Maybe I was ruined by my 64 Buick Wildcat's peeling mag wheels when I was 16).
  I had a chrome sprocket cover that actually peeled off by hand, I didn't even have to pay to strip it.
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Offline Bodi

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Re: 78 CB750 K Valve Cover Removal
« Reply #6 on: December 09, 2019, 10:59:14 AM »
Chroming aluminum alloy is complex, you need several pore free preplates before the chrome layer... I don't recall what metals. Even then, it's prone to corrosion under the plating if anything penetrates the plating... the alloy is soft under the hard plating and even a small pebble will break through... then corrosion spreads underneath and the plating just flakes off. I would recommend it only for show bikes that never go on the road.
Aluminum is very reactive, and far from chrome on the electrochemical scale. If it gets a chance to corrode, it will... quickly. There was a fad for chroming Honda engine parts in the 70s and I have never seen it stay intact for long on a ridden bike. Maybe in Arizona, but I'm in Toronto.

Offline 754

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Re: 78 CB750 K Valve Cover Removal
« Reply #7 on: December 09, 2019, 01:10:57 PM »
Don dress the cover flat on sandpaper.
 I had a chrome cover that was nice till I rode in the winter got some chemical on it plus I may have got some sat on it at Bonneville.. did not take it on the salt.
 But the chrome was  good from a good player and was fine from around 1987 to 2007.
 Many factory bike  come with chrome engine covers that are well done.

 Myself I prefer them, wash it, blow it off.. done..
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