Author Topic: 1978 CB750K8 Project Begun  (Read 1946 times)

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Offline pickingupdimes

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1978 CB750K8 Project Begun
« on: July 18, 2015, 05:33:35 PM »
So I've begun the building of my first Honda. I have it all torn apart and ready to be put back together again soon. The first place I want to start is the engine. It was seized when I picked up the bike, but I was able to free it with a little PB Blaster in the cylinders. Before I start tearing into the motor I'll need to order all sorts of fun parts. I'll take pictures of everything I can as I go along. And if anyone has any pointers I'm glad to hear them. I saw a decent thread about what parts to buy to rebuild an engine, so I'll be stockpiling those and getting to work as soon as they get here. As things move along I'll update this thread until I've got a thing of beauty to show off to all my friends.
1978 CB750K8
1981 GS550L

Offline Restoration Fan

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Re: 1978 CB750K8 Project Begun
« Reply #1 on: July 18, 2015, 05:57:14 PM »
Welcome.  The K8 is a great bike...I have one! 

At the very least, you're going to want new piston rings and cam bearings.  Also check the cam chain and cam chain tensioner, as well as the primary drive chain.

You'll want Hondabond or ThreeBond when you go to put the cases back together. 

You'll probably also want new valve seals and the set of rubber "pucks" that go underneath the cam towers.

Post plenty of pictures and questions when you have them.  The guys on this forum are unlike any other you'll find and are as helpful as can be.
Ron

Stella - Logan's Senior Project    78 750K http://forums.sohc4.net/index.php?topic=141761.0

Logan's Reward - CB500 and CB550 Cafes    http://forums.sohc4.net/index.php/topic,147787.0.html

Offline Restoration Fan

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Re: 1978 CB750K8 Project Begun
« Reply #2 on: July 18, 2015, 06:03:28 PM »
Also, I have a copy of the Honda manual that is specific to the 78K and 78F models shared on a Google Drive.  Help yourself to it and the parts manual, which are also there.  You definitely want to print both of those out.

https://drive.google.com/folderview?id=0B4nqeBb662mZZjZjTWdGRk9Qd0E&usp=sharing
Ron

Stella - Logan's Senior Project    78 750K http://forums.sohc4.net/index.php?topic=141761.0

Logan's Reward - CB500 and CB550 Cafes    http://forums.sohc4.net/index.php/topic,147787.0.html

Offline madmtnmotors

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Re: 1978 CB750K8 Project Begun
« Reply #3 on: July 18, 2015, 06:17:04 PM »
Welcome.  The K8 is a great bike...I have one! 

At the very least, you're going to want new piston rings and cam bearings.  Also check the cam chain and cam chain tensioner, as well as the primary drive chain.

You'll want Hondabond or ThreeBond when you go to put the cases back together. 

You'll probably also want new valve seals and the set of rubber "pucks" that go underneath the cam towers.

Post plenty of pictures and questions when you have them.  The guys on this forum are unlike any other you'll find and are as helpful as can be.


+1

Read through Restoration Fan's (Ron) project "Stella" thread. He went through the whole engine. My "Evolution" project (link in my signature below) is also a "resto-mod" of a K8 750. The motor I started with only had 20K on the clock so I couldn't bring myself to open up the bottom end. Glad I left it alone, shifts smooth as butter and runs great.  8)

Everybody knows the 78's are the fastest!  ;)
TAMTF...


Wilbur



Projects:
"Evolution": http://forums.sohc4.net/index.php?topic=100352.0
"P.O. Debacle": http://forums.sohc4.net/index.php/topic,126692.msg1441661.html#msg1441661
F2/F3 O-rings: http://forums.sohc4.net/index.php?topic=113672.msg1300721#msg1300721
Cam Tower Studs: https://www.mcmaster.com/#93210a017/=t19sgp
Clean up that nasty harness: http://forums.sohc4.net/index.php?topic=137351.msg1549191#msg1549191
http://forums.sohc4.net/index.php/topic,148188.msg1688494.html#msg1688494
http://forums.sohc4.net/index.php/topic,139544.msg1579364.html#msg1579364
                                          
Charging system diagnosis: http://forums.sohc4.net/index.php?topic=1012.msg8345#msg8345
Get the manuals: http://manuals.sohc4.net/cb750k/
The Dragon: http://forums.sohc4.net/index.php?topic=45183.msg1571675#msg1571675
Headlight Switch: http://forums.sohc4.net/index.php?topic=113986.msg1283236#msg1283236
Branden's leak free top end thread: http://forums.sohc4.net/index.php?topic=107040.0
Engine Lifting Made Easy: http://forums.sohc4.net/index.php/topic,58210.msg1684742.html#msg1684742
                                      http://forums.sohc4.net/index.php/topic,100352.msg1675840.html#msg1675840
Static and Dynamic Timing: http://www.hondachopper.com/garage/carb_info/timing/timing1.html
Airbox Gasket Replacement: http://forums.sohc4.net/index.php/topic,114485.msg1290000.html#msg1290000
"Café" : http://forums.sohc4.net/index.php/topic,84697.msg953814.html#msg953814
PD Carb Choke Linkage: http://forums.sohc4.net/index.php/topic,100352.msg1669248.html#msg1669248
                                    http://forums.sohc4.net/index.php/topic,110931.msg1248354.html#msg1248354
                                    http://forums.sohc4.net/index.php/topic,48858.msg515204.html#msg515204
Follow up on your damn posts: http://forums.sohc4.net/index.php/topic,144305.msg1791605.html#msg1791605
Taiwanese Cam Chain Tensioners:  http://forums.sohc4.net/index.php/topic,155043.msg1774841.html#msg1774841
Gumtwo Seat Cover: http://forums.sohc4.net/index.php/topic,164440.msg1897366.html#msg1897366
Primary Drive: http://forums.sohc4.net/index.php/topic,166063.msg1919278.html#msg1919278
Tank Latch: http://forums.sohc4.net/index.php/topic,165975.msg1919495.html#msg1919495
Shorten your forks: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-shorten-forks-td4042465.html DO NOT CUT THE SPRINGS!
Clutch How To: http://vintage-and-classic-honda-s.456789.n3.nabble.com/How-to-change-and-adjust-a-clutch-SOHC-td4040391.html
Late model K7/K8/F2/F3 front sprocket cover removal: http://forums.sohc4.net/index.php/topic,178428.msg2072279.html#msg2072279
630 to 530 conversion: http://forums.sohc4.net/index.php/topic,180710.msg2094423.html#msg2094423

Sent from my Tandy TRS-80!

Offline pickingupdimes

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Re: 1978 CB750K8 Project Begun
« Reply #4 on: July 18, 2015, 07:38:41 PM »
Thanks for the link to the manual. That will be a lot of help. I'm looking to take the top end off tomorrow and see the extent of the damage. From the way the frame looks I think this bike was wrecked, so there may have been some engine work done in the past. The odometer reads 40k, but its all smashed in on the back, so I can't say that it works. The frame has been broken and re-welded by someone who shouldnt have picked up a welder, but that's a bridge I'll have to cross when I get too it. For now I'll be focused on getting the engine into the best possible shape. I may even end up with bigger pistons and some of the other upgrades I've been reading about - including chains. I'll take lots of pictures tomorrow and put together a shopping list. I want one of the lightest, fastest, most powerful bikes around - and I'm looking forward to the work it's going to take.

If anyone is interested, I'm selling a 1976 MG Midget to finance the cost of this build. Only 50k miles, all original. Maybe I'll snap some pictures of that too.
1978 CB750K8
1981 GS550L