dirtdigger

This is a 750 auto? If so it sounds like the in gear idle kicker needs adjusted. The base carb idle needs to be set to spec, the idle...

hard to tell without hearing it

Cant be flat if its clean and dry or you are overtorquing the cover. Im guessing its not flat and has raised areas around the bolt...

I'm in

Im in

1000 +/- 100 is spec 1300-1400 you should be starting to get into the ignition advance and is where many people start having hanging or...

Have no idea. Might have to ask on a dedicated cb900 or 750 dohc page.

Left one is fine, right one is iffy.

I agree with that. As an automotive and heavy equipment mechanic you work on stuff that makes you frustrated and scratching your head...

A lot of things engineers do make you wonder. Adding another seal isnt the worst thing in the world. I am sure it all comes down to...

They are un necessary. Honda only used them because the earlier engines would seep oil after the cylinder studs relaxed and let the head...

The earlier cylinders didnt use the extra seals. Honda used the extra dowels and seals to try to stop the head gaskets from seeping oil...

yes F2 heads are a good starting point, you do have to do some work to convert them to use on K cylinders, There are pictures of almost...

The 72 will run pretty warm. Carrillo rods are about a must with that big of bore. Upgrade to heavy duty primary chains and tensioner...

105 to 120 main jet is a big difference, you should need 110 or 115 for a stock motor. What is the current main jet size and current...

Take it for a ride and when you get to the spot where it doesnt run right hold the throttle and start closing the choke...if its lean it...

Mark above T is top dead center or should be.

You wont gain that much compression. With modern honing techniques rings seat almost right away. If it was honed old school then yes...

836 is fine with stock rods, thousands have run with no issues, especially just a road bike. If you want to race or something then...

The other pistons started to seize as well just not as bad, you can see metal transfer starting. If the crank measures good i would at...

One tooth is a lot, If your chain is that stretched I would be afraid of it breaking at some point. You would have to set up a degree...

Well if its the same as before then it is something you didnt change. If you are sure the valve timing is off then you should probably...

you need to get accurate measurements, there were and still are a lot of different overbore sizes. Cyclex and dynoman are the big...

You need to look at every bearing surface in the engine. It has to have damaged bearings for the pistons to be that bad.

I dont understand you valve numbers, valve clearance needs to be .005" to .006"

Did they set the valve clearances for you? Get adjustable cam sprockets if they are available then you can time it correct with a...

In again.

Well looks like maybe run rich but also looks like a lot of oil being burnt. Top of piston isnt melted so dont think it was from...

Send some more pictures maybe.... What do the plugs look like comparing the good and bad cylinders