'78 CB750F Engine Rebuild

xxthegonzxx

xxthegonzxx

1978 CB750F-Coming along nicely!
So after many months of tinkering I finally started my engine rebuild. The reason for the rebuild was the low oil pressure I was getting which many said it was due to crank bearings. I also wanted to get my hands dirty and start learning by doing. By the way, I am no motorcycle mechanic by any means and I don't know jack about engines, but I have the Clymers manual and a big community of MC gurus online that have helped.
 

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Here's the valve cover off. Not sure what this is but it looks like there's markings on the inside of the head. You can barely see it but it says loct 1-1b or maby locx 1-1b? I dunno.
 

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top end is off and now you can see the black heads from carbon build up on the cylinders.
 

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Broke off the fin from the bottom corner trying to get this SOB off. It was so difficult to get the cylinder block piece off i had to use a very small screwdriver and gently tap all around to get it to come off. Stupid newbie mistake but I got it off, so problem solved.
 

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Can anyone suggests a good way to clean the cylinder heads? I'm assuming I can go to NAPA/Autozone/Pep Boys and just buy some sort of degreaser or maybe carb cleaner will do the trick?
Also, you can see that some of those long bolts are dirty and rusty as hell. No wonder the cylinder block wouldn't budge.
 

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Cylinders are now off and ready to be cleaned.
 

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I finished the weekend off by taking the stator cover off. I tried taking the rotor off but I didn't have that stupid Honda tool available. I ended up ordering a giant bolt off of amazon that should be the same size for me to take this thing off. I'm also having trouble taking the bolt off due the crank moving every time I turn it counter clockwise. I even tried holding the other end (the points bolt) and turning but wasn't strong enough for it to hold. I'll probably have my brother come help me this weekend and he'll have to put his weight on it for me to take the bolt off.
 

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Looks good so far! I'm going to have to do this to a CB550 engine soon, so I'll be watching closely. Like you I'm no mechanic. Hopefully some of the more knowledgable will chime in! If not, everything you need to know should be on this site somewhere! :)
 
LearnAsIGo! said:
Looks good so far! I'm going to have to do this to a CB550 engine soon, so I'll be watching closely. Like you I'm no mechanic. Hopefully some of the more knowledgable will chime in! If not, everything you need to know should be on this site somewhere! :)
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Yeah I just hope I get it back together in one piece. I'll be pretty damn proud of myself if I get it back together in working condition.
 
Well, I've gotten as far as I could. Now I require your help. I can't get the damn rotor bolt off. I've been trying to lock the crankshaft but so far have only managed to slightly damaged the case a bit. I don't want to push it too much but if anyone has any solution or suggestion on how to get this stubborn bolt off I would appreciate if. Here's a video link of my troubles:

http://www.youtube.com/watch?v=buUbMZ-NZWg
 
Use an air impact gun. You realize you do not have to remove the rotor to split the cases?
 
Yeah I realize that but I need to replace the crankshaft bearings so I figure this would make it easier.
 
Does anyone know where this came from? I'm pretty sure it's from the bottom of my engine because when I lifted up the engine to flip it over, this little ball bearing was lying on the floor. Any ideas?
 

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i have a 78 b750f also. its the bastard child of the 750s i feel like, so hard to find parts for lol go to sohc4 forums, good information, but they are kinda snobby over there
 
Calikid91 said:
i have a 78 b750f also. its the bastard child of the 750s i feel like, so hard to find parts for lol go to sohc4 forums, good information, but they are kinda snobby over there
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Yeah I heard Honda was just barely maintaining these because they were waiting for the DOHC's to finish production. I found out what it was. Turns out it's an old school neutral switch. I might have to replace it as it was falling apart in my hand. Good news is that I finally split the cases and will be inspecting them tonight for wear. So far I don't see any wear on the bearing shells but I won't find out until I remove the crankshaft tonight.
 
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