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Discussion Starter #1
this should probably go in newbie questions but here goes:

i just got new kawasaki 250sf. it seems good under 30mph. over 30 mph it feels like im on an ice skate. is there any MOD that i can do to give a more stable feeling. it feels like I could blow over or twitch over with a slight wind?

for the record: i am an active road cyclist/mtn biker/cyclocross rider and know how to ride but this is far twitchier less stable than i hoped for.

any help is appreciated.
jim
 

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if things get unstable at 30 mph you shouldn't be looking for mods but for problems. it's not normal for a bike to get twitchy at that speed.

have a good look at the front end, make sure everything is bolted down tight and that the wheel allignment checks out. check front tyre pressure to make sure it's not way low.
 

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Overly high tire pressure can be a stability issue. SM's need/want less air pressure then a typical streetbike.
If your pressure are right then there might be an issue with the bike, steering head bearings, etc. But check the tire pressure before you start looking for more complicated issues. It is usually the simplest explanation.
 

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If all of the above mentioned is in check... you need more trail in the front end. When the bike front end gets lowered from 21 inch to 17 inch wheels, the trail is too small and the bike will be very unstable at high speed. At low speed it will turn very well though. You need to either a) push the forks down into the triple clamps (lengthening the fork, increasing rake and trail) b) change front tyre height c) get smaller offset triple clamps

Also, if you make your rear end sit lower via spring preload or shock length it will increase the stability for the same above mentioned change in geometry.

These bikes all suck at high speed with small trail.
 

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The 250SF is a factory built SM. It should work right straight out of the box.
Other then checking sag and making sure it is in the ball park.....
It should work right. If it does not then something may be wrong. But, as mentioned, start with the easiest things first. It is rarely a complicated problem.
 

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Discussion Starter #7
twitchy front tire. do IRCs suck?

i now have 400 miles on the bike and I must say that the twitchiness that i worried about in the first two weeks is related to really bumphy, cupped, irregular road surface. i get on one road and i feel like i am on ice and marbles and turn onto a better road and i feel like v. rossi. i have had the bike up to 60 with confidence but some of these bad surface roads make me unconfidenT and like the front tire wants to dive out from under me.

one guy at the shop says tires are too new to swap and another says its the lack of tread that makes the tires irresponsive to bumpy roads. what are your thoughts?

ps i check tire pressure every ride and all bolts etc are tight. grip seems fine on 95% of roads in my area and grip seemed fine on the interstate too.
 
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