Lower top speed in hot weather??

You were doing 162k, on public streets? or a track? If on the streets.. ummm why? On highways anything over 120 will get you in trouble if caught. There's no need, ever.. for 160 or more unless it's on a racetrack. So it doesn't matter what your top speed is, you have no reason or legal right to come anywhere near it in public roads.
 
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+1 Save 162 for the track.
 
Johnny5 said:
You were doing 162k, on public streets? or a track? If on the streets.. ummm why? On highways anything over 120 will get you in trouble if caught. There's no need, ever.. for 160 or more unless it's on a racetrack. So it doesn't matter what your top speed is, you have no reason or legal right to come anywhere near it in public roads.
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Thanks Officer Dad! I had no idea!!
 
It's the same on any vehicle, though the power loss varies. It's the inflow density drop caused by an increase in temperature. Another one is elevation. If you've driven through the Rockies, you've see this too. Higher elevation air is less dense than at lower elevations. Sea level in February feels like tons more power than Rogers Pass in the middle of August.
 
invictus43 said:
I believe he is technically correct. For a given volume of "air"..there are less oxygen molecules..
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...but his post is misleading. Is he referring to a higher ratio of O2 in Cold air or is he referring to more of O2 & other gases in general?

It would be more appropriate if he said air is more dense at lower temps.

But back to OP's question, I highly double you would have that much HP loss from a 20*C difference.
 
Air temp only affects my top speed +- about 5km/h.

But a head/tail wind will greatly affect your top speed, especially on a ninja 250.
 
RockerGuy said:
But back to OP's question, I highly double you would have that much HP loss from a 20*C difference.
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Highly double ?

But, it does on a Ninja 250.

OP - I got the same issue going on, and so do most of the other Ninja 250 owners out there.

Related to the issue, you will also notice different RPM readings for a given gear and speed. For example, my Ninja will turn 4K rpm at 60km/h on 6th gear in the night, while it can go as high as 6K in the afternoon.

It's a new gen Ninja 250 problem as far as I know, and Kawasaki has no cure for it.

I am also interested in comparing Ninja 250s. PM me if you want to meet.

ps good job finding out the problem ONLY after riding the thing for 40,000kms LOL

edit: Check here for one rider's report on the issue, and here for the discussion by the Ninja 250 owners
 
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