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stock gearing,down hill? I'm super light have not hit 67 mph yet.. Im going to try a smaller rear sprocket to get my mph up. Thanks for a new goal to shoot for..
 

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With 740 miles on it, I've not gotten it faster than 55.

Now, I'm a few pounds heavier than most; but that shouldn't slow it down THAT much. As well, the main drag here has some undulations; and 58 is tops on the easy downhill slope. Then it drops down to 53.

Wondering if something's wrong. The engine seems to have a decided lack of torque at the low end, but I just figured, well, it's a revver. But I hear of these higher speeds others are making...
 

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You guys really have to mention if you are tucking or not. It makes about a 5 mph difference.
If I am about three car lengths in front of a car on a local highway with 55mph speed limit, I do not have to tuck in at all. I can hit 67mph. I try to keep more than three car lengths as much as possible from a car in front of me for safety.

When I am just cruising sitting up I can hit 60mph. Then when I tuck in I can hit 67 mph.
 

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Little things matter a lot for top speed on this bike. The other thing is the tire pressure. If you are running around 20/20 F/R which might be good for cornering traction at the track, the rolling resistance of that might cost you 1-2 mph in top speed.

In addition to tucking, size of the rider punching a hole through the wind matters too. 140 lbs 5'-7" might get 1-2 mph more than 225 lbs 6'-1". (I have no idea if this is true) But tiny differences in rolling resistance and aerodynamics will be huge on a low power bike like this. That's why we are going to see many different top speed numbers.

Just something to keep in mind.
 

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I was once apart of the 67mph club almost whenever I wanted but now 4000mi l8r and a few mods not so much :-(
 

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Little things matter a lot for top speed on this bike. The other thing is the tire pressure. If you are running around 20/20 F/R which might be good for cornering traction at the track, the rolling resistance of that might cost you 1-2 mph in top speed.

In addition to tucking, size of the rider punching a hole through the wind matters too. 140 lbs 5'-7" might get 1-2 mph more than 225 lbs 6'-1". (I have no idea if this is true) But tiny differences in rolling resistance and aerodynamics will be huge on a low power bike like this. That's why we are going to see many different top speed numbers.

Just something to keep in mind.
+1
Tire pressure is one of the things I always check whenever the bike is not hitting 67 mph.
 

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The fastest I've seen on my Z is 69 (hehe). I was tucking, going downhill, and had a tailwind. I am about 140lbs. I was pretty proud of that one. (Stock gearing)
 

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Little things matter a lot for top speed on this bike. The other thing is the tire pressure. If you are running around 20/20 F/R which might be good for cornering traction at the track, the rolling resistance of that might cost you 1-2 mph in top speed.

In addition to tucking, size of the rider punching a hole through the wind matters too. 140 lbs 5'-7" might get 1-2 mph more than 225 lbs 6'-1". (I have no idea if this is true) But tiny differences in rolling resistance and aerodynamics will be huge on a low power bike like this. That's why we are going to see many different top speed numbers.

Just something to keep in mind.


Yeah, What Zaph said. The fastest I have been on mine is 63mph ( indicated ) on flat ground ( no tuck ). But that is bumping the limiter. I am 6'00" 235 so just typically cruising around 56-58 is about all she will do. On the other hand....My Grom buddy weighs in at whole 150lbs, has the intake, Yosh pipe, and dynojet PCV on his and he can hit 67. I cannot keep up with him on long, flat road runs. There is no way you can make that up with that much rider weight difference on an approx. 9hp motorcycle. There is a reason that all MotoGP riders are 160lbs and LESS !
 

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I hit 70mph on the freeway the other day using a GPS. I was tucked to hit it though. Up one tooth front and rear with Dunlop that are a little taller than stock. I'm 205 pounds and the motor has been massaged a little. With tuning and different gearing I may shoot for 75.
 
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