Idle Issues

[ItchyPickle]

So I bought an 81 cb750c about 2 weeks ago. I've been trying to get it running, new battery, plugs, rebuilt the carbs, oil change. After all that I went ahead and started it up. The bike runs, but only on choke. I knew it could be a vacuum leak or clogged jets, so I took the float bowls off again and the jets seemed to be clear. there were significant cracks around the air box so just temporarily fixed those with flex tape lol. slapped it all together and still the same issue. it does sound better but same issue. when I was trying to test for a vacuum leak I went ahead and sprayed carb cleaner around the boots and couldn't seem to find a leak. I'm new to all this and was just looking for some guidance in the right direction. Something else that might be related is that the left 2 cylinders are producing white smoke out of them. not super thick but definitely noticeable. the other 2 are not. When I get the bike Idling good (on choke) the bike also kind of surges up around 200 RPM or so also. When I rev the bike, it likes to do like 2 smaller revs afterward that are not of my doing.
Please help,
thanks!

Karson

 

[Davidson750]

Did you do a compression test on each cylinder just to see what you're working with?

 

[ItchyPickle]

Eventually I did. I ended up tearing down the engine and found the cam chain tensioner had broken off and wedged itself between the crankshaft and the case. Since the rebuild the bike has been running perfectly.

 

[Davidson750]

Cool.