Need help solving headshake problem with '06 FE450

i've never had a problem with heashake once i set up the forks and rear suspension for my weight.

when i test rode it it shock like a wet Labrador until i got the front wheel in the air then it was smooth again but seriously it was because the fork springs where to soft for me and causing an excessively steep head angle

stupid question but you have got the right springs for your weight and your running the correct suspension sag? as this really is the first place to start.

when you say you have set sag to 60+ mm is this with you sat on the bike in your normal riding gear?

I reckon Cypher is onto something with the fork springs. I experienced a similar problem and cured it with $500 on new (stiffer) fork springs, revalve and a general rebuild. I think the front sag is the issue here. Have you checked that?

Your rear sag sounds about right and increasing it will flatten the head angle and reduce the problem which you have noted.

HI Tim,

I will second Cypher's suggestions!

According to your manual ..........if you are more than 80KG you should install the respective fork springs.............. Which would mean going from the .44 N/mm to .46 N/mm fork springs. Accordingly you should have an 8.4 shock spring. Not having the appropriate springs will have you chasing your tail for ever.

Too much rider sag and the front will have too little weight on it and will cause it to feel twitchy, and too little sag and the front will want to tuck.

The static sag on the rear should be between 30-35mm, and rider sag between 90-100, again, as per your manual.

Set the clickers per the manual, more than 5 clicks away from standard setting and your wasting your time, you need a revalve.

You should be able to feel a difference of one turn of pre load either direction on the rear shock.

Tell us a little about:

What type of riding you do.

What is your skill level.

Other questions for you:

Did you purchase this bike new?

When was the suspension last serviced?

How many hours are on the bike/suspension?

You mentioned the 04 bike, does it have stock suspension?

Where are you from?


Suggestion(s).

Have you tried loosening the triple clamps/axle clamp pinch bolts to make sure the front end is not in a bind? (this includes properly installing the front wheel)

Are the lower pinch bolts torqued properly? (over tightened? )

There is no money better spent than taking your suspension to a reputable professional and having it set up for your ability and conditions. Money can be replaced, time cannot.

Respectfully submitted,

Dale

I have heard the frame geometry is alittle different on the 06 from the 04, but I have never really noticed it much having owned both.
Gotta be something simple, wrong with the equasion here. I have never had the symptoms your having unless the spring rates were off.
I think swapping the 04 suspension might be a good start

i would have thought it more likely to be

wheel bearings rear
wheel bearings front
s/a bearings
top or bottom heim
headrace bearings
fork bushes

roughly in that order.

regards

Taffy

.

frame jigged incorrectly when welded.

Click to expand...

the 06 and 08 frames I have are both crooked from the factory, the centre of the swingarm and the centre of the headstock is off so they've twisted the frame to try to get it to align better.

FWIW I don't think that has anything to do with headshake, all the above suggestions are possibilites as is an intermittantly dragging front brake, I once had this problem and found a tiny stick stuck between the pads and the disc.

the stock rebound stack in the forks probably isn't helping either and you could try pushing the forks 3mm down below the top of the clamps (increase trail),

I had to have mine like that before I started revalving them.

I had the same problem with my 2002 supermoto. When I went over 100km/h any imperfection in the road would result in a death wobble. I then tightened the the nut that holds the steering stem in place. Worked perfectly no more wobbles, no matter how bad the road was. I gues it kinda works like a low budget steering damper.

Tim,

Send your suspension to Steve at Clean Racing. You will get it back, bolt it on your bike, and ride it. That's it. You will be happy with the set up.

without being there this is as always only a guess but id say loading the front more is perhaps helping to overcome packing.

if the fork springs are compressed further for a given bump they will come out quicker

try more prelaod on the fork springs, and experiment with the fork rebound adjusters near to full out. it won't be good for HS rebound (too soft) but it may improve the headshake sometimes caused by LS rebound being too stiff (packing)

if it does help a tad you might like to try a different rebound stack (PM me with more details if you like) or thinner fork oil.

if reducing packing doesn't work or makes it worse try less prelaod on the fork springs and a stiffer rebound setting.

I also had this problem with my '05 FS650c at high speed. After doing the sag thing with marginal results, the problem was solved by tightening up the steering head bearing and setting proper torque on the triple clamp nut. I know you checked the steering head bearing, but try tightening it up a bit (but not too much). Looking back, I think I caused the loosening from too many wheelies.

I find the head bearings on all bikes need a few good tightens to settle in so so what feels right quickly becomes loose again.

most people like their bikes handling better with the bearings really borderline tight