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Why is my new Husqvarna so slow?

7523 Views 21 Replies 18 Participants Last post by  Offcenter
Hi All,

I have been riding bikes for just over a year now and have just upgraded from a Mash dirt track 125 to a brand new Husqvarna svartpilen 125 until I am able to take my A2.

My reason for this post is that I am fairly underwhelmed with the performance of the husqvarna due to the fact that I haven't managed to get it to go faster than 52mph. This is made even more apparent with the fact that my previous mash which had 10hp would fairly easily be able to do 60mph.

Obviously, it is a 125cc with 15hp, so I wasn't expecting much to begin with.

However, having looked online and at reviews, most people seem to at least be able to get over 70mph without too much problem. (I am a fairly light rider as well - 70kg)

I am also aware that the svarpilen uses the same engine as the ktm duke 125, which is known to be "fast" for a 125, with it topping out at just over 70mph.

I was just curious whether the reason for the lacklustre speed was because the bike is new and hasn't been run in yet, or whether an aftermarket exhaust such as an Akrapovic or Leo Vince might fix the problem.

To be clear, I know it is only a 125 so please don't tell me it's not made to go fast, I am fully aware of that. I just wasn't expecting it to be quite as bad as it is.

Any advice or suggestions would be greatly appreciated.
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Nothing technically true about it without using proper model and numbers.

Note that cD is more important than A. Size of windscreen is secondary to its shape since it's still better than pushing piece of plywood flat-side facing wind. Putting rounded nose on house-brick will make it more aero even though it's blocking exact same amount of air.

There's a pocket formed by your arms and chest which directs air torwards torso that traps air into dead-end tunnel, not good. Better to reverse that pocket with nose-cone. You can actually double frontal surface area and still have less drag if shape is smoother. That's why bikes with fairings are significantly faster even though they block more wind. Total air-drag is.

Fd = cd*1/2*蟻*(v^2)*A
use 蟻 = 1.2 kg/m3 for air at STP

Note that while drag goes up by square-power of velocity, power-required to overcome that drag goes up by cube-power of speed. So to go twice as fast requires 8x more power!

A double-bubble windscreen on '08+ Ninja 250 raises top-speed by 2-3mph down front-straight at Thunderhill Raceway and 1.5-2mph at Laguna Seca. Helps air get over shoulders and back better than stock unit. New-gen '08+ windscreen way better than tiny '88-07 pre-gen screens that leave arms and shoulders in wind. Try skydiving to see how absolutely inefficient human body is at deflecting wind around it. Pretty much any windscreen is better than none because it's more aero than shoulders and arms.

Here's pre-gen Ninja 250 with windscreen about 10x larger than stock and significantly improves airflow. As measured by improved mileage from 55-60mpg stock to 116mpg!!! Top-speed would also be improved significantly as well, but wasn't tested and measured.


Only time bike without windscreen would be faster, is when there's no human on it.
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Fd = cd*1/2*蟻*(v^2)*A
use 蟻 = 1.2 kg/m3 for air at STP
Uhhh....Yeah, right.
I'll take your word for it. 馃ぃ
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