Author Topic: Wisohc's 78' CB750K  (Read 1553 times)

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Offline Wisohc

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Wisohc's 78' CB750K
« on: May 10, 2015, 05:53:14 PM »
A bit of a quick back story - I've been trying to buy this bike for 3 years and finally just a couple weeks ago the owner gave in and sold it to me for $500. The story goes that a friend of a friend (original owner) put this bike in my buddy's shed some odd years ago and let it sit. My friend acquired the title for it a few years ago in an attempt to get it running again but never got around to doing anything with it so finally he decided to sell it to me.

So without further ado here is what she looked like when I had the tow truck drop her off the other day:



Before the previous owner attempted to start the bike he went out and bought new plugs, a battery and cafe bars. Once all that was installed he threw the key in, hit the starter button, watched as gas started leaking out of the exhaust, pushed it back in the shed and closed the door. Somewhere in all the commotion the tank came off the bike which is why it's not in the picture but I do have it.

Knowing that's what happened the first thing I wanted to do was pull the carbs. I have a good bit of experience working with motorcycle carbs but this is the first time that I've ever really worked on a 4 carb set up and combine that with with the rubber mounts being as hard as a rock it took me a solid 2 hours to get to this point:




Once I got those boots off I shoved my camera in there and snapped a few pics to try and see what the inside was looking like:








Before covering up the holes in the engine I put a few drops of oil into each cylinder to give it time to soak in a bit before starting in case something might be stuck.







The first few bottoms of the carbs I took off didn't look too horrible:





Then I got to the second one:





I didn't understand why the one would look so much worse than the others but after a bit of reading I found out something along the lines of the second carb pumps(?) gas to the others to keep the bike from bogging down. I still have to learn more about it but at this stage that's what I'm going with as to why the second carb is the dirtiest.



Disclaimer= As of writing this I'm recovering from knee surgery (supermoto) so I apologize ahead of time is something isn't making sense.















Offline Stoli

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Re: Wisohc's 78' CB750K
« Reply #1 on: May 10, 2015, 06:31:38 PM »
Welcome. Sounds and looks like a nice find. Hopefully the tank is in decent shape. Looks to be all stock except for the handle bars and maybe the controls. If she turns over, then a good carb cleaning should be all she needs to get running. That model has PD carbs which has a "pressed fit" slow (pilot) jet unlike earlier models which were threaded. In order to clean it correctly, you'll need to remove them. I have rebuilt 2 '78Ks so I speak from experience.
My Project Threads:
Project #1 - http://forums.sohc4.net/index.php?topic=117106.0  First bike
Project #2 - http://forums.sohc4.net/index.php?topic=127364.0  Something different
Project #3 - http://forums.sohc4.net/index.php?topic=123831.0  Long and Low

Offline Wisohc

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Re: Wisohc's 78' CB750K
« Reply #2 on: July 07, 2017, 03:56:40 PM »
I'm long overdue for an update but I couldn't have done this without the help of all you guys here.