Squirrellyness going fast


12 replies to this topic
  • stknrdr

Posted July 19, 2006 - 02:24 PM

#1

So, I've had my 06 450f since february and I LOVE THIS BIKE. It has tried to hurt me a few times but only because my throttle hand sometimes writes checks my arse cant cash.

At any rate...yesterday I was on a ride that had some long straight gravel road sections and a bit of pavement (dont ask dont tell). Ive never really ridden it that fast but yesterday i had a chance to really wring it out in 5th gear...at about 3/4 speed in 5th it would start getting really squirrely ( a little side to side squirmyness that really made me nervous, both on dirt and pavement) Ive never really had a bike do that much...im wondering if its my tires (m59 on the front, Maxxis IT on the back) or if its some little adjustment somewhere I can tune out. I dont very often go that fast so its not a big deal, just made me kind of nervous, needless to say I backed right off on the speed.

Any thoughts?

  • yzfrider03

Posted July 19, 2006 - 02:38 PM

#2

If it was the rear tire squirrllying around then it just that same principle when your older brother made you go down the hill on the skateboard and you got "speed wabbles"...If you have wabbles in the front then look into a steering dampner to keep it straight. I have an 02 426 and i have the same thing when i open her up, but just the back im used to it know...

  • Baron Von Beard

Posted July 19, 2006 - 03:16 PM

#3

Non balanced spoke wheels that may be out of true can cause a whole lot of squirrelyness at those speeds.

  • grayracer513

Posted July 19, 2006 - 04:35 PM

#4

One of the hazards of riding on soft, uneven surfaces is that the center of contact between the ground and the front tire is not always under the center of the tire. Because the surface varies, the contact point moves around under the bike, and tugs at the tire alternately on either side as well as the middle. The wheel will follow this, and the result is sort of unsettling at times. It is axiomatic to a great extent that motorcycles that have light, quick steering have a more nervous feel at speed than those that feel heavy and unwilling to turn. But I have never really ridden a bike I thought felt extremely stable at high speed on any non-paved surface but a groomed and packed road or dirt track.

Having said that, I will tell you that when I ride one of my favorite MX tracks, there is a long, fast, downhill, which is followed by and equally long uphill that breaks to the right before dumping into and uphill right hand turn. It's choppy and varies between loose coarse clay and hard packed spots. The '03 shakes its head skittishly from near the bottom of the downhill all the way up, and the front skates and slithers through the right hand break. My '06 does none of that. The chop seems to vanish and the wheel tracks straight and holds.

If your rear sag is not great enough, or your forks are pulled up too far, or both, you could have too little head angle. Also, if you sit well forward and the front springs compress too much because your weight is more than the springs were made to support, the same thing could happen. Mine has the sag set at 95mm, and the forks are up to the first scribed line (5mm). The springs are stock, and I weigh 180.

  • stknrdr

Posted July 19, 2006 - 05:31 PM

#5

I think youre onto something there.....i did move the forks up in the clamps to help her steer quicker, and thats exactly what im feeling...lack of stability in the front...it just doesnt find center at those speeds. Guess what ill do is move em back down bit by bit until it goes away

  • grayracer513

Posted July 19, 2006 - 07:26 PM

#6

Check your sag setting and correct it first, then fiddle with the forks.

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  • jamiehughes

Posted July 19, 2006 - 08:04 PM

#7

you might also check the steering stem bearings. my 06 had like no grease in there from the factory and your steering stem adjuster nut(small slotted one on the bottom) may have backed off a little, you have to loosen the upper one to set the tension on the lower one. the bottom one just needs to be bareley snug, while cranking down on the upper one when done.. tightening the upper one will actually tighten the bottom one up some, so don't set the bottom one up too tight to begin with. these things will headshake like crazy if that nut gets even a little loose..

  • 2012 450 xc-w

Posted July 20, 2006 - 09:13 AM

#8

Is "Squirrellyness" really a word?

  • ncmountainman

Posted July 20, 2006 - 04:26 PM

#9

its the squirrelly ness monster,sighted all too often at high speed. i'm not too sure about the 06's but my 05 has a very fine line balancing between stability and agility. like grey said its all in the setup :thumbsup:

  • Nitroused383

Posted July 20, 2006 - 05:58 PM

#10

you might also check the steering stem bearings. my 06 had like no grease in there from the factory and your steering stem adjuster nut(small slotted one on the bottom) may have backed off a little, you have to loosen the upper one to set the tension on the lower one. the bottom one just needs to be bareley snug, while cranking down on the upper one when done.. tightening the upper one will actually tighten the bottom one up some, so don't set the bottom one up too tight to begin with. these things will headshake like crazy if that nut gets even a little loose..


Mine did the same thing (04). I was putting on a new triple clamp and noticed my top nut was almost backed all the way off!! I just spun the slotted nut down and tapped it with a brass punch and hammer (lightly) and than torqued everything down. It helped the high speed squirlieness so much. My bike is geared to do 85 and I'm often going that speed on some trails and the bike got a lot better but its still somewhat of a nervous side to side. My brother has a 2000 cr250 and that thing never feels nervous. Not sure the yz's just dont seem to have much high speed stability.

  • jamiehughes

Posted July 20, 2006 - 07:33 PM

#11

i don't think that you want to tap them tight, i was told by a mechanic at a yamaha shop they just have to be just past finger tight, you just want your bars to slowly drop to either side under the weight of the tire(if up on a stand of course). to get mine to that it was just barely over finger tight. i actually overtightened mine the first time as it got tighter when i torqued the top nut, so i had to take the top clamp off again and loosen it(i have since bought the spanner tool to tighten the nut with).

  • Nitroused383

Posted July 20, 2006 - 08:41 PM

#12

If you put mine on the stand and turn it halfway either direction it will just barely stay suspended. Barely touch it and it folds all the way over. I thought thats how u want it?

  • jamiehughes

Posted July 21, 2006 - 03:53 AM

#13

that's excatly what you want it to do.





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