General Question

futurelaker88's avatar

Is it bad to rev a motorcycle to almost red line in neutral while its warming up?

Asked by futurelaker88 (1600points) July 28th, 2009

does this harm the engine in any way? we’re still working on getting this thing to stay on without choke and my friend came over and he was like maxing the thing out all the way!! i dont know enough to tell if it sounded good or bad, but it sounded maxed out and got hot. is that what the engine is made for or is that bad for it?

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22 Answers

futurelaker88's avatar

also, i might add…he had it reved up, and then it started smoking and he said it was the plastic touching the exhaust near the muffler. it does look like its touching and it smelt like burning plastic…but WHY would it be touching?!?!? why am i having all these problems!?!?! i bought a 2006 bike with 177 miles on it that looks like its never been touched, and now i find more and more things that seem like problems! am i damaging the bike more and more?

Kiev749's avatar

normally the car company will “red line” the motor for about 5 minutes to test the engine under harsh conditions. its ok to go up to the red line, but i wouldn’t stay in the area for too long. and as long as it wasn’t smoking OUT of the exhaust, your ok.

futurelaker88's avatar

@Kiev749 it did start smoking out of the exhaust at the very end and it popped twice with a flame

futurelaker88's avatar

it was white smoke though not black fire smoke, and it was just like easing out when we shut it off, not pushing out smoke at all

Kiev749's avatar

did it smoke the next time you fired it up?

Kiev749's avatar

then i’d say your fine, just don’t push it in the red zone for too long. let it get about 3000 miles first.

futurelaker88's avatar

@Kiev749 ok thanks. now do you know anything about why it stalls everytime i take the choke off? is it dirty carbs, or do i just have to let it sit longer and warm up more and mess around more? how do i know if somethings wrong or if its just me?

Kiev749's avatar

yeah, that one i dunno. ..

futurelaker88's avatar

everything i look at says something different…ive heard

- dirty fuel lines
– dirty carbs
– gas tank has rust in it causing problems
– have to let it warm up longer
– carbs not in sync
– bad fuel/air mixture

i dont know all this stuff. this is my first bike and i wasnt planning on all this already (esp because its so new!)

andrew's avatar

@futurelaker88 It’s hard on your engine—not necessarily bad, but you don’t want to do it every time you start it.

The reason your bike runs better when it’s warm is that the gasoline evaporates more easily at higher temperatures (liquid gasoline isn’t flammable, believe it or not). Running your engine at 6 or 7K warms it up—quickly. It’s the equivalent of getting off your coach and sprinting a mile—it’ll get you warmed up, but it will be rough on you.

How long do you warm it up? Many bikes are “cold blooded” and need to be choked for the first 5 or 10 minutes you ride them. What brand/model of bike is it?

It’s possible you have a dirty fuel line, or dirty carbs, but that usually has more to do with poor power while you’re throttling. How does the bike ride once it’s warmed up?

If you haven’t already, take an MSF course. It might save your life—and it will make a much better rider.

futurelaker88's avatar

@andrew its a kawasaki ninja 250 (2006) and ive never ridden it yet. i dont even have a motorcycle license. i bought this, hoping i would have a great deal and i’d get my permit and license right away and start riding. i warmed it up today for about 2 or 3 minutes and if i touch the choke at all it stalls, unless i choke it more then it revs up to a higher RPM which gets me nervous. i heard that you should NEVER ride with the choke on. so you’re saying thats not true and i can even put the bike into gear and go with the choke still on!?

andrew's avatar

@futurelaker88 That’s a great beginner bike.

Just checking, you’re sure you have the fuel valve set to ON?

When you’re idling, what does the tach say?

Yes, you can run with the choke on (you’re just adjusting the fuel mixture,), but you really just need to let the bike warm up more. I’ve heard that Kawa are cold blooded.

If you idle it for 5 minutes, can you choke off without the engine dying?

futurelaker88's avatar

@andrew – yea the fuel valve is on, and the idle changes everytime i adjust the choke, but i can get it to freeze at about 1500rpm with some play. i havent let it sit for 5 min yet, as i read only 2 min on other sites. i can try that, but the only thing is that now the guy i just had over here was running it and it started to burn the plastic when he rev’d it high and he said the plastic was touching the exhaust pipe! idk HOW that happened or how to FIX it lol. so im scared to let it idle for too long before i get that checked out first

futurelaker88's avatar

@andrew youre a great help so far though! thanks so much!!!

LuckyGuy's avatar

I have the Kaw KZ 400. I let it sit for a couple of years and had similar problems when i resurrected it. The carb’s main jets were plugged with crud. I was able to drill it out by hand with a .028 inch drill bit. I am sure things have changed a bit in the past 25 years or so. It was very easy to take off the bowls and make sure the floats were working properly and there is not too much water / rust in the bottom.
It is possible the bike was in a flood and got water in the tank or carbs. Don’t panic.
You have a great deal there and it is definitely worth repairing.
If you can, look at the plugs. It sounds like you are lean so they should be white. If they are black, you are too rich and are overdoing the trick with the choke. Ideal, is the light tan color.

Zendo's avatar

You should let any engine warm up for a few minutes before pushing it so hard. You most certainly can damage parts in this manner. Moving parts often need to warm up and become properly lubricated before red-lining.
Mechanics who tell you otherwise are looking for your business.

Joe_Freeman's avatar

Regarding your original question (“Is it bad to rev a motorcycle to almost red line in neutral while its warming up?”): Yes, it absolutely is bad to do that. An engine should never be allowed to run at a high RPM under no load, whether or not it is warmed up. Doing that when the engine is cold is that much worse. I am surprised that none of those who responded to the question above mentioned any of this.

Depending on the ambient temperature, you should always warm up a motorcycle engine to some extent, especially if it is an air-cooled engine. During that period, keep the revs low and the load on the engine low, i.e., mild acceleration and moderate speeds. All this should be mentioned in your owner’s manual. If you don’t have that book, you might want to read a bit on the Web about how to treat a motorcycle engine. They are highly tuned and not as forgiving as automobile engines. But please, don’t ever rev an unloaded engine to high RPM for more than a second or so.

futurelaker88's avatar

@Joe_Freeman – yea thats what i thought, but this guy is better with that kind of stuff than me so i had him come to check it out and he started rev’n it up loud and messin with the throttle and choke and i asked him if he should rev it that high and he said “oh yea, thats what its made for, these bikes are made for high performance, and the engine will be fine.” so i hope now he didnt cause major damage to my new bike. cause that would make me mad.

andrew's avatar

@futurelaker88 Once isn’t going to destroy the bike (most likely), but good for you for asking. Have you gotten it to warm up? Did you sign up for that MSF course?

proXXi's avatar


Joe_Freeman's avatar

@andrew “Once isn’t going to destroy the bike”
I think if you contact the tech people at Honda, Yamaha, Ducati, etc., they might tell you otherwise. If the engine is under no load then it can easily overrev — unless there’s a rev limiter — in which case the valves can float, which in turn means possible valve damage, which in turn means a top-end overhaul. Maybe. So, no, the bike is not destroyed, but a top-end overhaul is not cheap on a fancy, high-performance DOHC engine.

“these bikes are made for high performance”
High performance involves a load on the engine, and is not at all the same as revving an unloaded engine. Your engine was designed to run at high revs with the bike at high (ground) speed, not sitting in your garage. Even on a dyno, the engine is under a load, not running freely.

So, are you screwed? Time will tell. You many never notice the damage, and maybe there was no damage. But if your engine needs a valve job at 10,000 miles you might ask your friend to pay for it. On the other hand, if you did not see the tach while all this was happening, you don’t really know how fast it was turning and maybe he never exceeded 4000 rpm, in which case maybe you’re in the clear. I sure hope so.

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