Author Topic: 78 CB750 Supersport - First build  (Read 1154 times)

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Offline ridevana

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78 CB750 Supersport - First build
« on: October 03, 2014, 02:36:19 PM »
First build for me. its 1978 CB750. Was sort of okay condition when I got her. The engine turned but had a lot of rust and hack jobs done on it before. Here are the pics as for now.


Offline Old Scrambler

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Re: 78 CB750 Supersport - First build
« Reply #1 on: October 03, 2014, 05:53:31 PM »
I see K carbs and manifolds.............

Why are you tearing down the motor?  What's your plan?

Did you keep the cam-tower and rockers in correct order?  Critical to re-install in the same places as worn-in.

You will find a lot of help along the way...............just try to minimize the re-assembly problems and start to take notes as you measure each bearing race and cam or crank journal.
Dennis in Wisconsin
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Offline ridevana

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Re: 78 CB750 Supersport - First build
« Reply #2 on: October 04, 2014, 09:42:34 PM »
Hello Old Scrambler,

This is my first build and I know its a too much for a newbie. I do have some experience with tear downs and machines (cars). My plan was to learn as much about how they are built etc. I have marked them and kept tags. I wanted to re-surface the head and check the cylinder/piston etc.

What did you mean by K-carbs and manifold? are they different for supersport or you suprised to see K-carbs (assuming you are talking about 750K)

I havent opened up the transmission. I might not tear it down completely. Any suggestions, comments on the transmission side?

Offline 70CB750

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Re: 78 CB750 Supersport - First build
« Reply #3 on: October 05, 2014, 03:09:19 AM »
You want to check the head first.  78SS is known for eating guides anywhere between 20-30000 miles.  There may be a full valve job in your future.

Get a spring compressor and take springs off and check for valve play in guides.  Specs are in the manual or Hondamans book. Exhaust side is usually worse. Also check valves stem for wear, the stellite coating is not thick, when worn out the valve contact will develop a dimple over the time.

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Offline calj737

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Re: 78 CB750 Supersport - First build
« Reply #4 on: October 05, 2014, 04:12:30 AM »
Here's a very informative thread for you upon reassembly-

http://forums.sohc4.net/index.php?topic=107040.0
'74 550 Build http://forums.sohc4.net/index.php?topic=126401.0
'73 500 Build http://forums.sohc4.net/index.php?topic=132935.0

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Offline ridevana

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Re: 78 CB750 Supersport - First build
« Reply #5 on: October 14, 2014, 08:01:57 AM »
Thanks Calj that is a very informative checklist. Will keep it marked for my rebuild.

Offline ridevana

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Re: 78 CB750 Supersport - First build
« Reply #6 on: October 14, 2014, 08:08:59 AM »
You want to check the head first.  78SS is known for eating guides anywhere between 20-30000 miles.  There may be a full valve job in your future.

Get a spring compressor and take springs off and check for valve play in guides.  Specs are in the manual or Hondamans book. Exhaust side is usually worse. Also check valves stem for wear, the stellite coating is not thick, when worn out the valve contact will develop a dimple over the time.


Will keep that in mind- I am currently getting the head done, so will keep an eye for it.

Ridevana

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