Gear Shifting Question

[cyber649]

Now this is a real noob question, but I like to understand how things work on my bike.

I have a '07 YZ250F. When shifting gears on the bike when it isn't running, the gears don't engage. But when the bike is running, the gears change. Why is this?

 

[cyber649]

Nevermind.. It shifts just fine when it isn't running. I was just being a bit retarded haha.

 

[sharky243]

There is no such thing as a stupid question. The transmission gears in all bikes are in constant mesh. When you move the shifter up or down to change gears, you rotate the shift drum. The shift drum has a set of groove cut into it with a specific patern. The shift forks ride in these grooves. The grooves move the forks back and forth, which engages each gear. The gears have cogs on the sides of them. These cogs engage with each other. The gears have to rotate slightly for the cogs to drop into each other. When the bike is not running the gears aren't rotating. This may cause the cogs to try to engage on top of each other. Take your finger tips and put each hand together finger tip to finger tip. Now rotate one hand slightly so your fingers drop between one another. Your fingers are like the cogs on the trany gears.