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Head snap back specs?

Posted: Thu Sep 06, 2012 12:44 am
by RoaringTodd
Is there any way you can determine the angularity and effect of a scooter's headsnap effect when accelerating from a standing stop?

When reading a spec sheet on a scooter, what numbers should I look for?

Posted: Thu Sep 06, 2012 2:20 am
by lovemysan
Why am I saying what what way ?

Posted: Thu Sep 06, 2012 2:35 am
by Skootz Kabootz
Headsnap effect? On the rider on the scooter? Or on the people watching the scooter go by? :lol:

Re: Head snap back specs?

Posted: Thu Sep 06, 2012 2:42 am
by neotrotsky
RoaringTodd wrote:Is there any way you can determine the angularity and effect of a scooter's headsnap effect when accelerating from a standing stop?

When reading a spec sheet on a scooter, what numbers should I look for?
Er...huh?

Posted: Thu Sep 06, 2012 3:51 am
by Tocsik
I first read this a couple hours ago and almost replied with: Um...are you serious? "Head snap effect" on a scooter?

Now that others have replied with my same :wha: reaction, I am comfortable asking just what inna heck you mean.

I don't want to be snarky, but what are you after here?
These things have like, 9-12 HP.

Posted: Thu Sep 06, 2012 3:57 am
by JAEGER
I think the word he's looking for is "torque."

In short, if you want torque, go check out the thread with the guy buying a 'Zuk S40.

--Jaeger

Posted: Thu Sep 06, 2012 4:51 am
by neotrotsky
If you are looking for off-the-line hard acceleration, a CVT scooter isn't exactly the best machine for that. Many are rather swift, but with the nature of the transmission, you just can't get that "rocket start" that comes with a manual clutch. But, torque ratings will give you a better idea of just how much "grunt" a bike has when it comes to physically moving weight from a standing point. Horsepower is much like a kW rating: It measures the energy output of a machine. It's the Torque that tells you what you can do with that energy in real-world numbers.

That is, if that's what you're looking for.

Posted: Thu Sep 06, 2012 10:58 am
by RoaringTodd
Jaeger - thank you for interpreting me. That article is helpful. I was not sure how to state it. It is the feeling you get when you turn the throttle from a standing stop, and your head snaps back...

Lack of terminology on my part -

Last night after I was in bed - I was thinking of the right terminology, and I came up with the "0-60" range the auto manufacturers boast.

Maybe Neotrotsky is right, torque...

Thanks guys -

RT

Posted: Thu Sep 06, 2012 11:42 am
by BuddyRaton
RoaringTodd wrote:
Maybe Neotrotsky is right, torque...

Thanks guys -

RT
Yep...he is. It is also known as launch when hitting it from a dead stop.

Posted: Thu Sep 06, 2012 12:56 pm
by RoaringTodd
Thanks - can anyone give me the torque or launch specification on the 170i? I'd like to compare that against the Honda Elite CH150.

Posted: Thu Sep 06, 2012 2:53 pm
by rentonhighlander
I'm not sure that manufacturers list torque specs on a scooter because it's usually not a performance charecteristic that scooter buyers look for and that scooters offer.

Posted: Thu Sep 06, 2012 3:00 pm
by skully93
rentonhighlander wrote:I'm not sure that manufacturers list torque specs on a scooter because it's usually not a performance charecteristic that scooter buyers look for and that scooters offer.
+1. Usually you can find the torque, but the difference inthe #'s is probably going to be so miniscule you won't be able to tell.

Best way is to test drive one, see how it feels to you. Then keep in mind that it will open up over the first few thousand miles.

Posted: Thu Sep 06, 2012 4:31 pm
by JettaKnight
RoaringTodd wrote: It is the feeling you get when you turn the throttle from a standing stop, and your head snaps back...

...

Maybe Neotrotsky is right, torque...



RT
Not torque, but acceleration. You're looking to measure "g-force" which is a unit of acceleration - 9.8 meters per second square, to be precise.

As a vehicle, upon which you sit, accelerates it essentially pulls your body forward. Your head can be modeled as a mass connected to a dynamic mass (your body and scooter) via a spring. Your head will try to resist moving - a body at rest tends to stay at rest. But, the spring can only stretch so far before it whips the mass forward. The faster you accelerate, more that spring will stretch before the mass is whipped forward.

Posted: Thu Sep 06, 2012 4:36 pm
by JettaKnight
rentonhighlander wrote:I'm not sure that manufacturers list torque specs on a scooter because it's usually not a performance characteristic that scooter buyers look for and that scooters offer.
And torque, as measured at the crankshaft (engine output), doesn't relate directly to acceleration. There's too many "power robbers" - the belt slippage, clutch slippage, vehicle weight, etc. and for each scooter model these will be different.

As for CVTs and acceleration, Buddy's aren't the best but can be improved with stiffer clutch springs and mainspring.

Posted: Thu Sep 06, 2012 7:57 pm
by JAEGER
RoaringTodd wrote:Jaeger - thank you for interpreting me. That article is helpful. I was not sure how to state it. It is the feeling you get when you turn the throttle from a standing stop, and your head snaps back...
No worries. :)

As someone with a lot more time on motorcycles than scooters I'm constantly aware of how little torque the Buddy has compared to my other scoots. Even my Bandit 400—which was a real pig off the line and was only really fun if you rode it like a 2-stroke—had more torque than the Buddy.

It's unavoidable given the size/power/configuration of the scooter engine. Considering the weight/geometry of the vehicle and the size of the tires, I'm not sure having 50 ft-lbs of torque would be such a good idea. (Accidental wheelies, anyone?)

Besides, smaller is more fuel efficient, which is a big consideration (at least for me).

I keep thinking about upgrading various components. "Ooh, I could put a big bore kit in it! A new pipe would sound awesome! And transmission upgrades..." However, I recognize that all of these things would ultimately reduce the usefulness, efficiency, and likely the reliability of the Buddy.

Besides, I have a bored-out full-sized bike sitting next to her in the garage in case I decided I need to blow The Ton or get on the highway. :mrgreen:
JettaKnight wrote:As for CVTs and acceleration, Buddy's aren't the best but can be improved with stiffer clutch springs and mainspring.
Yeah? See, that might be a worthwhile mod. What sort of "seat-of-the-pants" improvement does it provide (or does someone have actual dyno numbers)? What's the sacrifice? Shorter clutch life? (I confess, I'm still trying to wrap my head around how a CVT works.)

--Jaeger