Originally Posted by
BAMF
Cars last, what, 200k without needing a rebore.
They spin up to ~6-7k RPMs.
Bikes spin to 16k+.
That means that the bikes are scraping the compression rings agains the cylinder walls over twice as much as cars. There is no more basic wear and tear on a motor than the metal(alloy?) ring scraping the cylinder wall. Revving kills motors. So do other factors, but when you get right down to it, more revving means more movement which means a shorter lifespan.
Sure, things like stroke make a lot of difference, but you're still causing parts to move even if you've got a lil tiny stroke like sportbikes do.
dude, bikes are on a different level than we are used to in the car world. did you know most new high end bike motors have alum cly walls? yes, no steel sleeves in the alum blocks anymore. they just don't need it. and when you have the head off and tranny apart, they spin over by hand like they have no rings and roller bearing. its sick.
so yeah, more rshared_pm means the pistons go up and down more often, but its really a none issue. no bike i've every heard of has needed a rebuild because of worn out rings. in fact you can't even get a newer bike cyl bored local because its alum. gotta send it off. or atleast you did a few years ago when i was working with a buddy that built a turbo zx10 and melted a piston. oddly enough the cly didn't need any work even thou the piston looked worse than my car's did when i melted it on n2o. my block did need cleaned up.
its a wired world in bike land.