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Cylinder Head Inspection....and questions

To directly answer the question, lap only as much as needed and no more. if you encounter a black spot that will not disappear without more cutting, if it is lonely with no others and the gray surrounds it stop there too, the engine will not see it. Idea being to get them lapped but with as little material removal as possible. If one is really bad you may need a new valve.
 
Also, ebay is swimming with used heads, with cams and valves.

Since i have the chamber damage, can i slap a used head on this block? Would a cb900 head work? If not, can i reuse my camshafts if the lobes are within spec on a used ebay head? I hope you understand I'm trying to not invest hundreds of dollars on valves when i can probably scrap this bike and get another for the cost of new valves
 
I trust you amc...this is just to display how misleading the manuals can be.

grind.jpg
 
Yes, the aftermarket manuals are chock full of mistakes. They say you can split the cases with the alt rotor still on and wrong and call the ignition a CDI type when it's not. Later editions of some of those books removed that circled part you have there. I have one of each.

Somebody has already done something with head or below it, you have damage to it but not the pistons or deck on that cylinder. Yes, you can switch but then anything different like cams forces all the tappet shims to change. 900 head works but slightly bigger chamber and drops compression a bit. If you have early small stud head then exhaust studs for pipes got bigger later.

Valves when run get a slight indent matching where they contact the seat and why you need to keep them in order. Used ones from elsewhere CAN work but trying to pick them to match that indent location is a pain. When you lap intending to get rid of the indent edges by slow cutting due to the lap then you commonly wear through the valve nitride again. You are looking to only remove as little as possible, a heavy lap to match valve to another seat is often too much.

I understand about the cash but these pig bikes were always some of the most expensive to fix, why racers didn't go after them nearly so much as the SOHC. They didn't make as much power as they could have either due to the crap intake porting. Getting to 150 hp. not too hard but any single hp. past that really made you fight for it even on the bigger ones like the 1100. And when you did they then broke way too easy. Why Vance & Hines only ran an 1100F one season in pro stock to take advantage of the rules due to nobody running them, then dumped it, way too many limitations where a Kaw or Suzi just got faster and faster.

Why so many don't run when you get them either, even the dealers commonly passed them through without all the shim setting needed if they ran well and were quiet, it took way too much shop time to do 100% of the job. Take the money and run, what all business does if you give them a chance to think about it.
 
Ok....so I'm going to try and rebuild this as is and perhaps seek that KZ1000 that this project really needs in the future. I think for my first attempt at a project like this, I've learned a lot thanks to your efforts amc! If i can get this thing back together even if i have to custom shim the thing. I'll gain a ton of experience at least. And a running motorcycle for $250 and some old fashion elbow grease, definitely a plus..I get restless if im not takinging something apart and puting it back together...

Help me with reassembly please. Im just worried about that stupid timing tensioner system.....grrr

Thanks amc! You're the best!
 
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Hello, I am working on my grandpa's 1971 CB750 K1. He bought it in 1971 and used it until about 1985 when it sat in a garage on a dirt floor. Surprisingly, there is very little rust and the pistons aren't stuck. The kick starter turns over just fine. I haven't tried starting the engine yet but I noticed this on the right side of the engine at cylinder 4. Now I am not a professional at all, but to me, it seems like a casting issue from the factory, just because I don't see any corrosion. The motorcycle used to run just fine so I am curious as to what this is, or if it is a problem. As of right now, I do not have any more pictures or close-ups of this issue. Let me know what you think this is and feel free to drop a comment. Is the whole engine trashed, or is there still life for this old Honda?

Thanks,
Daniel
 
1

Hello, I am working on my grandpa's 1971 CB750 K1. He bought it in 1971 and used it until about 1985 when it sat in a garage on a dirt floor. Surprisingly, there is very little rust and the pistons aren't stuck. The kick starter turns over just fine. I haven't tried starting the engine yet but I noticed this on the right side of the engine at cylinder 4. Now I am not a professional at all, but to me, it seems like a casting issue from the factory, just because I don't see any corrosion. The motorcycle used to run just fine so I am curious as to what this is, or if it is a problem. As of right now, I do not have any more pictures or close-ups of this issue. Let me know what you think this is and feel free to drop a comment. Is the whole engine trashed, or is there still life for this old Honda?

Thanks,
Daniel
It would be best for you to start a new post as you are piggybacking on a post that is over 6 years old and in the wrong category for your model bike.
 
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