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 Motorcycle Safety
 General Discussion
 Staying in the power band
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kiddal
Male Advanced Member
1561 Posts
[Mentor]


SE, Indiana
USA

Kawasaki

KLR650
Peer Review:

Posted - 05/21/2005 :  7:13 PM                       Like
I think a good tip I heard (maybe from one of James' articles, I don't recall) is to keep your engine in the power band. If you need to accelerate hard for some reason, you can just twist the throttle and not have to downshift.

It's probably a little more important for those of us who ride bikes with modest engines. Between 4000 and 6000 RPM my bike does pretty well but under 3000 RPM it accelerates like a Ford Pinto with a hole in its muffler (I have some knowlege of this ).

I constantly find myself cruising at 3000 RPM in town because it's very smooth and quiet and the bike is not the least bit "edgy". But I think it's better to cruise around at 4000 RPM because it will accelerate quickly if I need it. I keep having to remind myself of this and it's not yet really habit.

I've been paying attention to other bikers shift points and notice other people may be doing this as well. I listened to one guy today who could not have been going 25 MPH when he shifted into 3rd gear.

I just thought I'd throw this topic out as food for thought and possible discussion. The DOT vs. Snell thread is dying out. I need something to think about.

Notes

Since we have people from all over and varying experience levels, the term "power band" is usually used to describe where your engine makes the most power. There is a range of RPM where the engine will make good power and below and above that range performace will drop off, substantially in many cases.

The RPM examples are for my bike. It really doesn't rev very high (7500 red line). Your bike will probably vary significantly.


fz6yamaha
Standard Member
242 Posts


USA

Posted - 05/21/2005 :  7:58 PM
My bike red line is 14k rpm, so when I started I was holding it on 4k, it was smooth but accelerating would take a little bit of time, so a friend of mine told me, "sport bike-try to keep it half way of you top red line" so in my case now I keep my beast at 6k to 7krpm (crusing, not crusing), after 8k rpm the beast got a lot of power so I figure from 7k to 8k it will not take as long as it used to from 4k to 8k. My bike is not loud at all, so If I keep it under 4k, people do not even know I exist.
I have found that keeping it on the 7k I accelerate much faster when passing a car and like you said I do not have to downshift, therefore do not take part of my brain attention, that is focus in thousand stuff all around me at that time", also if I keep it that way it is easier for me to remember what gear I am on.
Also when I used to up-shift at 4k, everybody would leave at the traffic light, I was paying attention and caught that one of my friends from work (who rides a 600-something -ninja -green kawasaki) with loud pipe will up-shift long after he left me at the traffic light, so I asked him and he told me my line of power is at 8k, so if I rev over that, at the time I up-shift I do not lose my power and can keep on going without having to up-shift so many times. I found that was true in my case, I was up-shifting so many times, by the time I would reach him I would already shift almost up to 4th or 5th and my bike was not fast enough.
Now,taking off from a traffic light I speed up in 1st up to 5-6k, gives me about 20-24mph- 2th give all up to 45 at 6-7k and after that I am good, I know I am not a speedy GonZalez, BUT got the advice from the MSF teacher (off the record-that was her preferences),(she got a HD-NEW SPORTIER SOMETHING) she told me I take off safely from 0-to 50 in about 3 seconds, I do not like to have a lot of people behind me trying to run me over.
hope it adds for the discusion.
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Mydlyfkryzis
Senior Member
274 Posts
[Mentor]


West Milford, NJ
USA

Honda

1991 Nighthawk 750

Posted - 05/21/2005 :  8:10 PM
quote:
Originally posted by kiddal

accelerates like a Ford Pinto with a hole in its muffler (I have some knowlege of this ).




My understanding of the Pinto is it actually accellerates quicker with a hole in its muffler

quote:
Originally posted by kiddal

I think a good tip I heard (maybe from one of James' articles, I don't recall) is to keep your engine in the power band. If you need to accelerate hard for some reason, you can just twist the throttle and not have to downshift.



I agree keeping the engine in its power band gives you better response, but there are drawbacks. Lower MPG, Noise, vibration, etc. With some bikes, riding in the sweet spot of the power band can mean an UNintentional wheelie if the throttle is suddenly applied. Not good in most situations.
I generally keep my bike at lower RPMs in general to keep the negative down. However, if I am in a situation that indicates I will need responsiveness, than I keep it in a better zone.

My CB360t doesn't have any power below 5k RPM. it has a 10.5K redline. In traffic, in an urban area, I keep it at or above the 5k start of power. However, when the situation is less "tense", I will let it drop somewhat. The charging system is weak on this bike, so keeping the RPM's up also keeps the battery charged. I wouldn't ride around in the 8-9k range though, I think it is too hard on the negine, and it also doesn't leave much acceleration left before I need to upshift anyway.

So my advice would be to consider the circumstances and ride accordingly.

Edited by - Mydlyfkryzis on 05/21/2005 8:23 PM
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DoubleDip
Senior Member
262 Posts


Erlanger, Kentucky
USA

Yamaha

650 V-Star Silverado

Posted - 05/22/2005 :  5:42 AM
I've got a 650 v star twin and the mfg. yamaha only provides shift points which are at 10, 15, 20, and 25 mph for up shifting to 2, 3, 4, and 5, respectively. Now I do not have a tach on the bike but I can tell we are not talking about very high rpm here. So my question / comment is how do I tell how much is too much and where is my power band. I ride without putting too much stress on the bike however it is good to know the limits. I have been able to understand from the posts that I read that the V Twin engine doesn't run at the high rpm of some of the other engine styles but can someone give me some info that yahama did not.
Bruce
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kiddal
Male Advanced Member
1561 Posts
[Mentor]


SE, Indiana
USA

Kawasaki

KLR650

Posted - 05/22/2005 :  10:21 AM
quote:
Originally posted by DoubleDip

...yamaha only provides shift points which are at 10, 15, 20, and 25 mph for up shifting to 2, 3, 4, and 5, respectively.



Holy cow. That's unbelievably conservative. Hard to believe they would tell you to be in 5th at 25 MPH. That would really be lugging the engine, I would think. It's hard to believe you wouldn't be safe by doubling those speeds at least. Not having a tach is really annoying.

Your bike surely can handle 3 times those RPMs because 75MPH in 5th would obviously be 3 times the RPMs that 25 MPH in 5th would be.

quote:
Originally posted by DoubleDip

...but can someone give me some info that yahama did not



I would try a Google search to try and find someone that has done a dyno test on that engine. That will give you a good idea of where the power band is. I found one for mine in a similar fashion.

Short of that, you should be able to feel where your acceleration is strongest at. There will probably be a 1500-2000 RPM range where it is better. After a while, you'll be able to feel it when you're in the right range.
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JuniperBug
Standard Member
115 Posts


Montreal, Quebec
Canada

Kawasaki

Ninja 600R

Posted - 05/22/2005 :  10:31 AM
I agree with everything Kiddal said. I think that the owner's manual speeds are more the minimum speeds you should shift at. I say this because even on sportbikes they state similar shift points as to what you describe, although many bikes can exceed 60 MPH in first gear. As to how fast exactly you have to go in each given gear to get into the power band, I don't know; my experience is in inline fours. However, I'm sure you can go faster than what the manual says. When you get into the powerband, the bike starts to pull considerably harder. I imagine that on a twin, this feeling will go away (you'll be out of the power band) before you reach redline. The sound of the engine will probably bother you before you hit redline, as well. Your bike may also have a rev limiter, which would keep you from being able to over-rev the engine.

Sorry I can't provide more specifics for your particular bike, but I hope this helps at least somewhat. Everyone else feel free to chime in.

As for staying in the power band, I rarely do it unless I'm accelerating onto the highway. My bike is old and quite loud, so constantly revving at 6000-11000 RPM - my powerband - doesn't appeal to me. Besides, power is relative. During in-town riding, any RPM above 4000 is enough to outaccelerate most cars, more than enough power. I don't see any emergency situation requiring more than that. In my opinion, anyone on a 600cc+ sporty 4 cylinder bike who claims they need to be in the power band in the city for safety reasons, is riding too close to the limit. The only exception to this I can think of is if you're being chased by a Corvette or something. Anytime I rev more than 7k, it most definitely is not safety related.
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kiddal
Male Advanced Member
1561 Posts
[Mentor]


SE, Indiana
USA

Kawasaki

KLR650

Posted - 05/22/2005 :  10:43 AM
quote:
Originally posted by DoubleDip

...can someone give me some info that yahama did not.



Look at http://www.motorcycle.com/mo/mcyam/...star-dyn.gif

It looks like it's best between 5000 and 6000 and pretty good at 4500 or so. Fairly similar to mine, really. I'm sure you can take the gear ratios and figure out the speed equivelent in each gear. May be more trouble than it's worth.
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DoubleDip
Senior Member
262 Posts


Erlanger, Kentucky
USA

Yamaha

650 V-Star Silverado

Posted - 05/22/2005 :  12:50 PM
Thanks for the ideas about the dyno test, even if I have to do a little math it would at least give me some number to refer to. I know what you mean about feeling the power but without a tach I'm a little afraid of straining something. Well we'll work something out.
Thanks again,
Bruce
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DoubleDip
Senior Member
262 Posts


Erlanger, Kentucky
USA

Yamaha

650 V-Star Silverado

Posted - 05/22/2005 :  3:52 PM
Well you know after doing just a bit of research on figuring out just how the numbers would fall. And considering I don't have a tach and considering I am not really interested in pushing the envelope. I have deceided that my ears (damaged though they are ) and the seat of my pants (not damaged) will do nicely for judging just where the "power band" for my scoot is.

I was never really good at physics.

But thanks for the help, I did get a good dyno chart for my engine and from it I believe the range would be between 3000 and 6500 rpm. There is, I'm advised a Rev Limiter that kicks in at 7200rpm. So there is plenty of room for these damaged ears to make a mistake.
Bruce
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kiddal
Male Advanced Member
1561 Posts
[Mentor]


SE, Indiana
USA

Kawasaki

KLR650

Posted - 05/22/2005 :  6:34 PM
quote:
Originally posted by DoubleDip

...I believe the range would be between 3000 and 6500 rpm.There is, I'm advised a Rev Limiter that kicks in at 7200rpm. So there is plenty of room for these damaged ears to make a mistake.



Yeah, I doubt you'll really come close to the rev limiter. 7200 will probably sound likes it's really screaming to you.

I don't think I've ever had mine over 6,000 and there's not really any reason to as it quits making power north of there.

If you ever do hit the rev limiter, it will feel kind of like it does when you run out of gas. Of course it will be back to normal when the revs drop.
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kiddal
Male Advanced Member
1561 Posts
[Mentor]


SE, Indiana
USA

Kawasaki

KLR650

Posted - 05/22/2005 :  11:34 PM
For anyone interested, James wrote an article on how to map the speed to the RPM if you don't have a tach.

http://www.msgroup.org/TIP094.html
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kiddal
Male Advanced Member
1561 Posts
[Mentor]


SE, Indiana
USA

Kawasaki

KLR650

Posted - 05/23/2005 :  5:15 PM
DoubleDip,

Since your bike has similar power and RPM band as my bike, I took a look at the speedometer for 5000 RPM upshifts. That's a pretty normal upshift spot for me. 6000 for more acceleration and 4000 for just modest acceleration.

1->2 - 25 MPH
2->3 - 40 MPH
3->4 - 50 MPH
4->5 - 60 MPH

I doubt if your bike is significantly different. Actually, these are probably fairly reasonable shift points for almost any 5 speed bike. 4000 RPM is roughly 10 MPH lower and 6000 roughly 10 MPH higher, except for 1->2 which would be plus or minus 6 or 7.

I checked to see what 25 MPH in 5th would be. About 1500 RPM, barely above idle. I didn't try to accelerate from there, but I'm sure the results would be similar to sitting at idle.
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DoubleDip
Senior Member
262 Posts


Erlanger, Kentucky
USA

Yamaha

650 V-Star Silverado

Posted - 05/23/2005 :  6:00 PM
quote:
Originally posted by kiddal

DoubleDip,

I checked to see what 25 MPH in 5th would be. About 1500 RPM, barely above idle. I didn't try to accelerate from there, but I'm sure the results would be similar to sitting at idle.


Al,
Thanks very much for going to that trouble for me. You are right about the 25 in 5th is like. I'll have to look next time I ride and see where my ears tell me to shift and I'll bet it is very close to the figures you have provided.
Thanks again,
Bruce
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