Topic: 1972 CB750 Basketcase find - ENGINE NOW TURNING

[lucky]

At 16,000 miles the bearings are ok. The bottom ends are really strong.
When you take the clutch plates out to get them unstuck you can look into the inside of the engine and see the cam chain rollers and bottom end of the rods.

But like I said if you take the cylinders off and then put it back together without honing or new rings it will smoke. And it won't quit smoking.

I do not see the point of doing all the work you are doing and then putting it back together half assed just to hear it run. You know it will run .
You want it to run RIGHT. Winter is coming. Just take your time and do it right.
Then next summer you will be able to ride it and it will not need to be taken all apart again.

[lucky]

Hey guys, for the engine, I'm still not decided. There are two of three points plate mounting locations still there and I think I can get a third by drilling a small hole (carefully) and inserting some thread and JB welding it in place. After that, I'm not sure. I've shown it to a few folks in the know and the feelings are mixed.  One even said, just don't ride in the rain...

For the engine, agreed that it needs new rings, or could and also all new top end gaskets.  But, things being things, I'm going to put it back together with just a new head gasket just to try to start it. If I can get it to turn over, then I'll tear the top end apart again. My fear is that a bearing is bad or something worse, so I don't want to put a lot of $ into the top end of this, also considering the damage, until I hear it run. It sucks I had to pull it to get it free, but after I did, it was good that I found that stuck valve - still stuck.  I work on it a little every day.

I removed the oilpan recently, looks great. Amazingly, the engine is clean inside, at least what I can see.

My Theory:  This bike was bought and quickly laid down on the right side. Evidence: Cracked case, mangled points plate, bent and damaged (but still OK) turn signals, scraped right foot peg, damaged right grip, and a minor dent in the tank.  That was a bike killer, so it was rolled next to a garage and traded, and swapped and who knows what.  Knowing that, I think it's fixable!  I'm optimistic if nothing else!

Everything is fixable. The question is do you want to do it?
For all you know the bike was hit by a car in a parking lot.

[SUELZER]

I do not see the point of doing all the work you are doing and then putting it back together half assed just to hear it run. You know it will run .
You want it to run RIGHT. Winter is coming. Just take your time and do it right.
Then next summer you will be able to ride it and it will not need to be taken all apart again.

I have to agree with lucky on this one. You've definitely got an uphill battle ahead of you, but from what i know about your projects you'll get everything right. Sounds like a good winter project for you and your boy!

[lucky]

Your son looks very excited by this project and he will remember it all his life. I would think. It is a good model of how to do things in the future.

[CycleRanger]

I respect your optimistic perseverance!

[Rio_CB750]

Thanks Guys, You've convinced me, I'm going to put the engine back together right, I'll speed up getting that gasket kit and I also need a new bolt kit at bare minimum.  The cylinders will be easy, I have a hone and I'll get some rings.  Looking back, you're right. I have never done this level of work on a motorcycle engine, but have on cars, and I think I was getting a bit optimistic because it reminds me more of the lawn mower engines I worked on rather than the car engines. 

Today, I got one of the circlips off of the old forks to replace the seals and now...the polishing begins. I'll post pics!