Say your riding in first gear and you keep the throttle wide open and dont shift from second, I know it would get really loud, and still go slow, but what would happen if you kept holding the throttle down?

Is it bad to do that?

Does it burn more gas?

It also brings the engine RPM's past its red line. Hold it open for to long and the first bang you hear will be the piston coming thru the head. The second and subsequent bangs will be all the internal moving parts shattering.

Well it would start getting really hot first after about 30 secons it will start billowing out black smoke after about a minute or so it the piston will get so hot it will melt and fuse to the barrel so yes its bad and the wider open the throttle the more petrol os used

Say your bike is air cooled, and say it is going fairly slow, and say you have the throttle wide open... I cannot think of any potential issues concerning thermodynamics. Can you?

1. Burn more fuel

2. Overheat engine

3. Turn engine into hand grenade.

If you have to ask this question I am afraid that you need lessons.