I have seen a lot of people talking about the Power Bands of their bikes. Do Power Bands change with every gear? If so, what are the Power Bands of every gear for the f2?

 

the engine's sweet spot really doesn't change with the gearing - the motor makes the same power in 1st as it does in 6th.

The "Power Band" is just where the engine is making good torque & hp numbers. For our bikes, it's in the 3500-8000rpm range if I had to guess (assuming the engine tune is good). I've always hear of people talk about having "power bands" in their dirt bike, like they're physical things - but honestly I think most of them have no clue what they're referring to. I guarantee people have pulled their 2-stroke motors apart trying to find them.

Just find where your bike makes good power and try to keep it in that range - do a rolling dig in like 4th gear from 2000rpm. You should feel where that torque takes over and stay in it til you can see it is running out of breath

 

Okay that makes sense. Ill try that out either tonight or tomorrow. Thanks

 

Yeah, It's not really 3500-8000....

Torque rolls off past 6200 pretty fast, while HP gains significantly from there. You can feel it when riding the bike solo VS two up. Two up I find myself staying around 5-7k to use the higher torque for better pull. By myself I stay above 7 grand as much as possible to maximize pull.

 

I would say that the F2 has (had) most power 6 or 7K to redline.

I rode my friends 600rr and it was at about same 6 or 7K starting point up to a redline 2-3K higher.

 

By the way, intereting little bit of information from a recent cycleworld:

If you've ever looked at a HP and Torque graph, they always cross at 5250 rpm. Why? Because horsepower is actually calculated by taking horsepower, multiplying it by RPM, and dividing by 5250. Therfore, if you take say... 100, and multiply it by 5250 (rpm) and then divide it by 5250... you get 100 and therefore they cross.

What causes torque to drop off while horsepower still gains however is volumetric effeciency. Essentialy after a certain speed the motor is unable to fill the cylinders as effectively, and the torque therefore drops. Horsepower still gains though as the motor has all that momentum and is still gaining.


They also discuss in that magazine a bit about "powerband" in a discussion of a previous article comparing I think a harley and a japense cruiser. They discuss how wide smooth powerbands are very comfortably and easy going, while sharper ones are a bit more unruly.


I would be interested in seeing a recent CBR600 dyno sheet and discuss it in here. Unfortunately i just cant seem to find one using Google search, and I have not dyno'd my bike myself. I honestly have been feeling dirt biking a bit more lately, since I can enjoy it without the fear of running into government sactioned highway robbers (aka... cops)

 

jesse i think you mean to say that tourqe=HPx5252/engine rpm and HP=tourqe x rpm/5252... check out this link. you were close though. http://www.iprocessmart.com/techsmart/formulas.htm

 

Ahhh yeah, I got the order mixed up

Given that the two are a function of the other, I suppose a dyno can read both really. I always just read they tested "true" torque and the horsepower measurement was merely a derivative.


Anyways, thanks for the link to that. Now I just want to see a darn F2 dyno sheet. If I had the spare money I'd dyno mine, it could probably use it anyways!

 

here is the dyno chart for a 2000 F4. It is as old as I could find (so far), but should look fairly similar to the F2. I had a link bookmarked to a site that had a dyno chart for f2, f2 f4, f4i, 600rr ect, but when i upgraded my system to Win 7 i cant get all my bookmarks to load back. I will still try to find the site again.

http://www.sportrider.com/dyno/146_s.../photo_61.html