Why hayabusa engine can run over 10000 rpm not like car

[mestona]

Not all bikes rev high

 

[Defiant]

Lots of factors for this but the primary reason is the strength of the materials. You can have bigger engines with higher RPMs but the 'tensile' strength of the materials will determine the amount of stress they can endure and how long it can endure it for under what conditions. Also engine design has a lot to do with it also. Since we are talking piston engines they have the same design stresses so 'Moving' mass determines rpm limits. Keep in mind a piston engine cylinder has to reverse directions 180 degrees to keep the crank moving so you can look at it like this:

A fat guy doing shuttle runs, can't do a lot of em because he has to move his fat ass in 1 direction and completely reverse it. He can't do it that fast but he does generate a lot of momentum, Mass * Velocity. His stubby little legs and shoes can't reverse his direction that fast, 'tensile strength'. More 'torque'.

A skinny guy doing shuttle runs, can do them faster because he doesn't have as much momentum and his legs and shoes can reverse his directions.

Switch engine designs to a turbine and things change but that's another homework problem for ya.

We are just talking about the pistons here not the crank or tranny etc.

Smaller engines=less moving parts. Bigger engines more moving parts. The more parts the more mass, the more mass the more likely stuff will not get out of the way in time. Valves floating out (not closing fully before the are being shoved open again) could result in pistons hitting them and when stuff hits internal it breaks. You can do things to help this issue (stiffer springs), but this is just one problem amoung many that can happen when you over rev a motor. (Mine leaned and blew a hole in the piston, but mine was NOS related )

Reason for the higher rpm's in a motorcycle is for the torque out of such a small motor. Bigger STOCK motors with bigger pistons don't require or need the rpm's to make the torque.