RPM

[Dirtytoes]

okay, so i was riding my ex almost allll day today with a friend of mine who has a new R6....just going from one place to another picking people up and dropping em off...for like 5+ people....i was like a shuttle....had to deliever 6 dominos pizzas too....it was yummy

anyway, first off, my bike maxes out at 13k RPM.

after that we went on the freeway and raced a few times, on the street too....his R6 obviously has ALOT more hp/power than my ex but when i went to high revs i could keep up with him.....that was around 11k-12k....(redline).....and it was LOUD as f*ck.....then, when i shifted up, the bike slowed down and he'd pass me.....

if you know me, you know that i know NOTHING "technical" about bikes...what happens if you redline once in a while? i'm guessing it messes up the engine, thus the color red AKA danger......what exactly does it do to the engine?

[Sev]

I wuoldn't worry tooo much about hitting reline occasionally. That's the speed at which the stress the moving parts are under starts reaches the point that it can begin to damage them. It's sort of like taking an erasor and rubbing it against a piece of paper, if you do it slow and it's one of those nice smooth erasors it just takes off the pencil. If you do it fast with the same type it takes off the pencil.

But if you get one of those cheap pink ones and rub it really fast, it'll just eat a hole in the paper, though doing it slow causes no damage.

Personally I'd be willing to go close to, but prefer to stay away from redline.
My bike seems to have best acceleration between 5 and 10k rpm anways.

[Dirtytoes]

My bike seems to have best acceleration between 5 and 10k rpm anways.

i hadn't ever redlined until last night....and it has ALOT better acceleration over 10k rpm.

[J.R. Bob Dobbs]

Inline japanese bikes love to rev, they're designed that way. I think they should handle near-redline riding OK.

My 750 Nighthawk makes its peak power at 8500rpm; redline is 8600rpm, only 100rpm away. It seems very happy running steady at 7000+ rpm.

My 250 Rebel is sometimes right at redline in top gear at normal highway speeds(85mph), and will do it all day long with no complaints.

As long as you don't run the engine so fast that it floats the valves (unlikely), nothing's getting "hammered" as it runs, and as long as there's sufficient oil pressure, there's virtually no metal on metal contact inside. Redline RPM is usually determined and limited by valvespring design (to avoid valve float) and oil pressure (safe rule of thumb is 1000rpm for each 10psi of oil pressure).

The parts most stressed by high RPM are the connecting rods and crankshaft, and broken Rods and Cranks are very very very uncommon on japanese bikes. Rods and cranks don't really wear, they either break or they're fine.

Edited to add some detail, I'm an engineer and know lots about car engines but admittedly not much about bikes specifically. The rule of thumb of 1000rpm/10psi is for a car with about 3.5" stroke, a bike has a shorter stroke so would be able to very safely exceed that before centrifugal force overpowers the oil pumps ability to supply oil to the rods.

Enough rambling, I say rev it up to redline without worry.

[J.R. Bob Dobbs]

OK I'll add more.....

I have a mechanic buddy, who had a 450 I2 Honda. He ran the pi$$ out of it, greatly exceeding redline on a regular basis. He tended to ignore the tachometer and shifted it when the valves floated (sudden loss of power and backfiring as the RPM gets so high that the valves don't have time to close all the way).

He put over 40,000 miles on that bike, no problems, no oil burning etc. Who knows how long it would have run, had it not been for a left-turning-lady collision which totalled the bike.

[The Grinch]

i was riding my ex almost allll day today

You da man!

[Sev]

i was riding my ex almost allll day today

You da man!

Lawl

[flynrider]

The redline is there to tell you not to exceed that rpm. Going right up to redline should not be a problem. I've done it on nearly every bike I've owned in the last 25 yrs. with no ill effects.

If you constantly ride around at or near redline (i.e. near max power output), you can expect that your engine will wear faster than a comparable bike that doesn't run at redline rpm. At max power, you have the highest cylinder temperatures and pressures, and this will cause some wear. While the engines are designed to reach high rpms, they're not expected to run there all day long. If you only do this occasionally, I don't think you'll have a problem.

BTW - running above redline is not a good idea for two reasons. One, it exceeds the design limits set by the engineers who built the engine. And two, just about every bike I've ever dyno'd has it's peak power output at one or two hundred rpm below redline. So, if you're trying to go fast, you're not helping yourself by running above redline.