Engine knock at start up...
 

Alright, I'm not too worried about this, but maybe I should be?

When I start my bike...it starts pretty rough, and there is a very obvious knock, but the tach reads a bit less than 700 RPM, I don't have the choke on since it's warm out...however if I give it a bit of throttle (1500-2000RPM) the knock is instantly gone, no rough idle and the bike stays on. I'm thinking I need to adjust the idle thing...but mine seems pretty locked up, like I can't twist it by hand.

Ideas?

Once I get the bike warm it idles smoothly, and no knock under acceleration or normal riding.

Thanks!

The choke was designed to be used anytime the bike itself is cold, not just when the temperature is cold. It enrichens the fuel mixture until the engine is warm enough to run on the normal circuit, which is usually around 120 degrees. I'd suggest using the choke until the bike warms up. You'll know its warm once the rpms raise and hold steady.

700 rpms is way too low. The rpms need to be high enough for the combusting cylinder to carry the rest of the cylinders until they fire. The knock your hearing could be the crank slowing down and all of a sudden speeding up from the combustion, so you get this sort of slap. So your getting this slow down, speed up, slow down type of action. Sorry, I don't know how to put into words. But its not good on these engines to idle too low.

I'd use the choke and/or get your idle set higher. If it still knocks when its idling at a normal idle speed, you may have other issues. But the knocking seems to be related to the too low of an rpm.

Okay, I had been using the choke before without issue when it was colder, but the Clymer I got said not to use the choke at all is it was like 60F or something out.

It is a slap, it makes the entire bike shudder, I figured it was due to the idle being so low. Will use choke from now on, thanks!

Definitely use the choke. Once the idle rises with the choke on, turn it off. The reason people tell you not to use the choke too much is because it will foul the plugs over time.