Head Shake Issue - Different Suspension Settings for US/ Canada /EUR / NZ/ AUS

[meWR250f]

I am dealing with a nice head shake on acceleration and in reading the manual again I have noticed the asterisks for the standard suspension settings. So you have different standards for the suspension depending on where the bike is sold. Especially fork settings, shock settings are almost identical.

Does anyone know why?

 

For my headshake, what I read was that it can be corrected by:

- increasing sag

- increasing front compression

-reducing front rebound

Also found people stating that too stiff of a fork bounces of the bumps and causes the same effect.

 

Even though the 2006 WR250f manual says that sag has to be between 90-100mm, I have it set now at 104-105, with static sag at 35. Also plan to set the fork to the european standard, softer with a bit less rebound. But that after I try the increased sag.

Does anyone know if the rapport of static/ race sag has to be 1/3?

[ronbuell]

You might also check your head bearing.  If there is not enough tension on the bearing, it will shake.  I've got 2 bike that will hold the same position when I put them on the stand, third bike flops to one side or the other when on the stand; and when I ride it, it head shakes.

[meWR250f]

@ronbuell Good point, read about that too. Mine keeps straight on the stand, turn it a bit and it would go all the way. No play in the head bearing, is that what you mean?

[ronbuell]

Yeah, there's 2 nuts on the steering stem.  The one under the top tree has special catches on it, sort of like the nuts on the rear shock that hold the spring.  Tighten to 27 ft lbs, then loosen 1 turn, then tighten back to 5.1 ft lbs.

[meWR250f]

might sound like a silly question, but what do you use to you torque that nut to the values you mentioned? I have the regular torque wrenches and I use them all the time but from that to using the flat wrench to tighten that nut...?

[ronbuell]

Steering wrench from Yamaha.

 

Or you can use a drift pin and guess at the setting you need, which is what a lot of guys do.  It's not the best way, but it does work. 

Edited May 16, 2014 by ronbuell

[meWR250f]

Had the chance to try the bike on a very slippery motocross track. With the sag at 104-105 I don't have the head shake any more. Also tested the slower rebound(2 clicks) and softer front (2 clicks) just like Europeans have it. Change is subtle, can't say I noticed the difference on this muddy track. I will report back. 

My conclusion - just like everything else on these bikes, do your homework and be sure you know the steps then go for it! I am amazed of how much info is out there and how much can be done in your own garage.