Reving while stoped....

[brasileiro]

hey i have a question...i was revin my bike on my driveway for no reason just to hear it(full Hindle)same as the one on AMA 7R's can u blame me ..any way i reved it about 4 times to 10000 and then my uncle comes out and was like wtf u doin ur going to mess up ur engine .....i can see how it would mess stuff up if i was redlining the thing but i took it to 10000-11000 max...7r's redline at 13...Can anyone shine a light on this i made a $10 beat with my uncle that it doesn't doin anything as long as u don't do it allll the time.....I NEED MONEY lol

[999Duc]

Pay your uncle and thank him for not slapping you.

[Jackal79]

I've heard it isn't good to rev an engine more than half of redline without a load on it. Not sure though.

[brasileiro]

lol i jus payed my uncle....but ya i didn't know that messes things up...i guess that means no more reving lol

[grasshopper]

Originally Posted by brasileiro

lol i jus payed my uncle....but ya i didn't know that messes things up...i guess that means no more reving lol

Get your $$ back. You can't hurt the thing by reving it like that. New Jap inline 4's are virtually indestructable.

I've seen guys rev there motor up for minutes at a time banging it off the rev limiter turning the kill switch on and off to make it back fire and the thing still runs fine.

Beat the shit out of your bike and love doing it!

[rocketjoe]

Originally Posted by 999Duc

Pay your uncle and thank him for not slapping you.

thats only if you have a Duc

[KatanaMike]

"Pay your uncle and thank him for not slapping you."

I agree - and thank your neighbors for not getting in line to help him..

[mysubaruimp]

You cant hurt it by doing that.

But- You are a moron for doing that. I would pay your uncle just cause he didnt slap you. I bet you are the type that revs the crap out of it at lights too, no?

[HalfLiterBeater]

It would be nice if somebody offered a technical answer here! I've heard the same thing all my life about car engines. One guy said it's very hard on the bearings...but I'm trying to imagine what would be different about an engine revving under load, and not under load. The oil pressure, if the pump is working properly, should still raise oil pressure dependent on the rpms, regardless of load or no load condition....so oil delivery shouldn't be an issue. I'd really like to see this one explained!

[jim schmidt]

He obviously needed to come up with an explanation to get you to stop being irritating. ;-)

[evils-03-RR]

This comes from the good ole years when engines were less efficient and revving an engine not under load could throw a bearing. Not really teh case anymore, but older people are hard to persuade from there ways.

[MAGNUM636]

It would be nice if somebody offered a technical answer here! I've heard the same thing all my life about car engines. One guy said it's very hard on the bearings...but I'm trying to imagine what would be different about an engine revving under load, and not under load. The oil pressure, if the pump is working properly, should still raise oil pressure dependent on the rpms, regardless of load or no load condition....so oil delivery shouldn't be an issue. I'd really like to see this one explained!

On the technical side, revving the engine without a load on it is hard on the bearings and is proven to stretch out connecting rods. Think about the amount of inertia each piston/conrod must overcome to change directions at the top of its stroke. When the engine is under load, the rods face compression forces, which seat rings, bearings, and even the rods themselves. Tensile (or stretching) forces are much more taxing on metal parts, therefore it's not advisable to rev an engine in neutral-- and especially during break-in when all those parts should be "loaded-up" in order to seat themselves. In an extreme example, an engine still in its break-in period was revved through the roof, it eventually threw a rod, but measurments of the other rods showed that they had indeed stretched and the valves had kissed the piston tops.
I also suspect that you're not doing your transmission any favors by revving it in neutral either. I don't know much about bike transmissions, but someone on here must. As you all might guess, my car knowledge is high while I'm still learning a lot about bikes. However, an engine is an engine is an engine-- get air/fuel in, time optimal cylinder pressure, and get air/fuel out-- no matter what.

[mysubaruimp]

Originally Posted by MagnumRider

On the technical side, revving the engine without a load on it is hard on the bearings and is proven to stretch out connecting rods. Think about the amount of inertia each piston/conrod must overcome to change directions at the top of its stroke. When the engine is under load, the rods face compression forces, which seat rings, bearings, and even the rods themselves. Tensile (or stretching) forces are much more taxing on metal parts, therefore it's not advisable to rev an engine in neutral-- and especially during break-in when all those parts should be "loaded-up" in order to seat themselves. In an extreme example, an engine still in its break-in period was revved through the roof, it eventually threw a rod, but measurments of the other rods showed that they had indeed stretched and the valves had kissed the piston tops.
I also suspect that you're not doing your transmission any favors by revving it in neutral either. I don't know much about bike transmissions, but someone on here must. As you all might guess, my car knowledge is high while I'm still learning a lot about bikes. However, an engine is an engine is an engine-- get air/fuel in, time optimal cylinder pressure, and get air/fuel out-- no matter what.

How would it matter if it was under load at the flywheel or not? The pistons are forced back down by the explosion of gas, making compression at the top, under load or free wheeling. Whether they come to the top under load or not doesnt matter. They are spinning at the same RPM, so any force that is trying to stretch them will be the same, regardless of resistance at the flywheel.

[2002 Busa SE]

you wont ruin anything, over-reving will screw it up but all sport bikes have a SOFt limiter, you can hold it floored and it will just bang off the limiter, never getting anymore RPM's, didnt they do a test in a sportbike mag, with an old F3, they let it run and got the headers red hot, i think it even melted the fairings, the engine wouldnt blow.

[999Duc]

Originally Posted by jim schmidt

He obviously needed to come up with an explanation to get you to stop being irritating. ;-)

+1