"Headshake"

[MrM0t0]

Did my homework using Google to search the site with no luck.

I installed my forks and Penske shock from GP suspension some weeks ago. Started getting a strong vibration in the front end at about 90 mph. Not a wobble that feels like it may progress to a tank slapper, but just a big vibration. GPS RAM bracket shakes back and forth as opposed to side to side.

Put new PR2s on last week (same tires as were on before) hoping that this might resolve it. No luck.

It doesn't change based on acceleration or deceleration, just past 90 it shakes (just short of violently).

Various threads say it's not the steering head. I have 28K on this '08 AE.

Could the orientation of the tubes in the triples affect this? When I installed the front tire the axle was perfectly flush on the right side before tightening the pinch bolts, so I don't think my forks are tweaked.

Any ideas are appreciated. The bike used to ride like buttah at all speeds and this is not enjoyable during high speed passing etc.

 

[JamesK]

Like you said, there are numerous threads on this, and as these show, whilst new tires and correctly torqued head stem nut will help a little, they will NOT solve the problem if you're running bags and topbox...

What WILL solve the problem is upgrading to Roller Head Bearings. I did mine only a couple of months ago and couldn't be happier, only benefits and zero issues. Do some searches on AllBalls Roller Bearings threads and do the upgrade you'll be happy...

 

[bwv]

Can you check the runout on your brake rotors? Take a look at them for deposits or discolored spots

 

[MrM0t0]

Like you said, there are numerous threads on this, and as these show, whilst new tires and correctly torqued head stem nut will help a little, they will NOT solve the problem if you're running bags and topbox...
What WILL solve the problem is upgrading to Roller Head Bearings. I did mine only a couple of months ago and couldn't be happier, only benefits and zero issues. Do some searches on AllBalls Roller Bearings threads and do the upgrade you'll be happy...

I thought I read that head bearings wouldn't solve this problem, and it was my first thought. I will commence forthwith. It seems like a logical solution.

Can you check the runout on your brake rotors? Take a look at them for deposits or discolored spots

No visual evidence, but I'll lift the front and check for that with the proper tool.

Thanks gents!

 

[900gc]

Didn't whack a pot hole or the like to bend the rim a bit? Check the run-out with an indicator both vert. and horz.(both sides) and the rotors while you are at it. The tire doesn't appear to be the issue since you changed it and the problem still exists.

 

[Nanahanman]

I installed my forks and Penske shock from GP suspension some weeks ago

This info is not clear. Did you install different forks or re build you stock forks....or what?

As your bike was OK before the fork install, it would be useful to try to go back to your original fork install to see what effect it has.

 

[kamal]

I installed my forks and Penske shock from GP suspension some weeks ago

This info is not clear. Did you install different forks or re build you stock forks....or what?

As your bike was OK before the fork install, it would be useful to try to go back to your original fork install to see what effect it has.

+1

I'm guessing the forks were re-valved, stiffer springs etc?

After installing a Traxxion AK-20 kit in my forks and a Penske shock, it took a while to get the bike set up to how I like it - still not quite there.

I would suggest double checking your fork compression, rebound and sag settings. In my case, the much stiffer rear spring appeared to be putting too much load on the forks? Backing off the shock pre-load helped a lot.

FWIW. I doubt it is the head bearings. Did you re-pack and re-torque them while you had the forks off?

Good luck with this.

Al.

 

[gumba]

MrMOTO - had the same experience as you with 1 exception. I had the head shake before and after GPS and Penske. Went to new tires - no help. The only thing that has saved my ass is meticulous front end alignment (specifically torquing the lower triple clamps first). One word of caution; watch axle placement as you torque down the pinch bolts. The Gen2 pinch bolts are off center and as you torque, placement will walk all over the axle. I have put 10k on 2 front tires with no head shake (they looked like shit but no 45mph h,s.) This all with all with 90k on OEM steering neck bearings

 

[Duezzer]

Gumba

When you talk of the "placement will walk" what do you mean

Just put a new tire on and have a head shake now.

Is there a certain sequence you follow putting the wheel back on.

I follower the tourque specs for all the front end bolts

Thanks for any help - the head shake is frigging annoying -

 

[JamesK]

Gumba
When you talk of the "placement will walk" what do you mean

Just put a new tire on and have a head shake now.

Is there a certain sequence you follow putting the wheel back on.

I follower the tourque specs for all the front end bolts

Thanks for any help - the head shake is frigging annoying -

I'm simply reposing my statement from above. Why, because it works - 100% guaranteed

There are numerous threads on this, and as these show, whilst new tires and correctly torqued head stem nut will help a little, they will NOT solve the problem if you're running bags and topbox...
What WILL solve the problem is upgrading to Roller Head Bearings. I did mine only a couple of months ago and couldn't be happier, only benefits and zero issues. Do some searches on AllBalls Roller Bearings threads and do the upgrade you'll be happy...

 

[FJRUtah]

I have a similar problem at speeds between 35 -40. All front end parts are OEM. Any help or others having this same prob?

 

[gumba]

When you come down with the torque on the front axle pinch bolts, there are 2 per fork tube off center, the tube will walk on the axle. Not much (.000s), but it is enough to knock the fork tubes out of parallel. I like to lay a straightedge across the end hole in the slider and look for the axle to just kiss the straight edge. I know this sounds pretty anal but it is the only thing that has worked for me. Put a flashlight under the straight edge. It will give you a pretty good picture of where that axel is at. I've heard of new tires and steering neck bearings correction h.s., but I often wonder how much could good alignment on the install.

 

[supertankerm60a3]

I have had the low speed shake problem. For me it was a simple solution Tire Pressure. Check it, maybe raise or lower it.