Front end slop
 

Let's see if anyone here can help me identify a problem.
Symptom: a slight slop, loose, click feeling after when rolling over a dip (pot hole) or after hitting a bump. Especially pronounced if at lean.

What I have done so far. New wheel bearing, new steering head bearings, tried all balls, and now on OEM. Rebuilt forks by suspension shop, new tires, rim straightened and balanced at GP Frame and Wheel new brake rotorsn new brake calipers.

So WTF!

I can't see any cracks in the frame around the steering head.

Have I done something wrong?

Question why didn't the Allballs tapered bearing work?

Have you lifted the front end and rotated the steering bump stop to bump stop? If you don't detect any looseness in the front end, then I would suspect the problem lies in the front suspension.

What have you done as far as front suspension maintenance? Change the fluid, check the springs, etc. Depending upon the mileage, it maybe time to change the fork fluid. There are several threads about changing the fluid and the air gap you want to have is 155mm.

Are you serious? You replaced all that stuff and still didn't find the problem? Wow!

Is the feeling in the whole bike, or just the bars? Have you checked all fasteners? Maybe a loose bolt on the fairing stay, or even a loose motor mount? It's stretching a bit, but possibly there is something rattling around inside one of the clip-ons? Make sure your triple clamps are properly torqued. Also, remember that new steering head bearings will loosen up a bit after a few hundred miles, they then need to be tightened.

This might be a stretch but since you've tried everything else-

Sure your fork tubes are each at exactly the same height?

Sure your fork preload adjusters are at exactly the same height?

Past that I'd either get rid of it or take to GMD Computrack for a diagnosis.

I would re-torque those head bearings, if the procedure was not done correctly, they could be under torqued. The steering should feel tight, with the wheel off the ground if you can turn it with one finger, it's probably too loose.

Thank you all for your responses. The motor mount is something I haven't checked. I have untorqued, and retorqued, the bearings. When the front is hanging from a rafter in the garage I can freely move it back and forth with no binding or excessive free play, and there is no slop I can feel when moving the forks back and forth, front to back.
The suspension has been completely rebuilt by a professional suspension company so it isn't inside the forks especially since I tried another set of forks I have and the problem was still there.
Fork hight is correct, clamps are all tight.
Bike has been digitally mapped for straightness and is less 1% out of alignment from front axle to rear axle (pretty good for a bike that has multiple crashes, and 85k miles)
Yes the feeling is in the bars. I can feel it in my hands when I do get that slop.
The interesting thing is I only notice the problem when the front end is unloading. Like when I hit a pot hole, or after hitting a bump.
This is why I can't find the problem when lifting the front end in my garage. It is already unloaded.
The only other thing I can think of is that the steering bearing cups in the frame aren't aligned.
That is why I removed the all balls bearings, and put the oem ones in thinking I had installed them wrong or something, but I doubt I'd do it twice.
However if the inside of the frame that the bearings seat into is worn or damaged then that could be an issue, but I'm grasping at straws here.

Just to verify... you did swap the bearing cups with the supplied ones when you went to the All Balls right??? (Just figured I'd ask)

J.

of course

Just a thought.... There are spring damped weights inside the fairing stay that could have come apart.I had a slight vibration issue when accelerating,turned out to be one of the springs vibrating because the weight was loose.These are the same as the weights inside the stock clip-ons.If you pull off the rubber plugs at the top of the fairing stay you should see what I mean...... Like I said,just a thought.

Thank you, but this is not a vibration it's a definit movement that translates into a click or knock in my hands when it happens.
To clarify there is very little stock about the front of this bike. Body work, fairing stay, headlight light bracket, all modified, or aftermarket, forks brakes, wheel 929, clipons heli, I've had this set up since 2002 and everything has worked well. I'm on my 4th or 5th set of steering bearings. The bike has a lot of hard miles, and gets the shit pounded out of it riding around the streets of San Francisco.

There is one other thing I have heard of,but not seen.That is wear in the buttons that are between the brake disc itself and the hub mount.It is possible that ANY slop here could translate into movement at the bars under braking.......Hope you figure this out,would annoy the crap outta me!!

Thank you for the reply I thought of that. In the original post I note that the brake rotors, are new.

professional shops still make mistakes... it sounds like you have gone over everything else except checking the internals of the forks. Just my 2c's. If you already checked and rechecked everything else its time to remove what you might think is a constant and switch it back to a variable.

That is a valid point, but I've tried that. I took my original forks off, and sent them out for service, and borrowed a set of forks from a friend hoping there might be a difference, and then I would know, unfortunately the problem persisted no matter which set of forks I used. The issue is not in the fork.

Just of of curiosity... anychance it's something in the rear suspension??? You mentioned you noticed it as the front forks rebound anychance the same time the rear is just hitting the hole/dip/etc??? I know this is a long shot... but if everything on the front has been checked 2-3 times and is good... maybe your feeling something thru the chassis???

J.

:eek:

What's the condition of the tire? Other than that I'd start as SlowHAWK said, looking in the rear...

Check the rear suspension and lower links for slop/binding... Swingarm pivot bearing...

All of it could potentially translate to the bars... Unlikely... But once you have done the obvious it's time to start on the unlikely stuff...

Yeah I had that thought. The rear shock is a very new OEM piece (ebay) with new linkage and such. It's worth looking for some slop in the swing arm, but I don't feel it in my arse I feel it in my hands.
I'm in my 6th year of road racing so I'm pretty good at feeling what a bike is doing, which is why this is KILLING me to not be able to figure it out.

Okay, I know it's a dumb question, but I have to ask.

When you install your fork tubes & triple trees do you tighten the tree clamps around the tubes 1st or do you tighten the steering tube through the frame 1st?

I torque the steering head nut, then torque the triple trees, but that is worth double checking.

With that thought. The top torque nut is really old, and has been taken on and off many time. I wonder if it is torque-ing against the frame, and not putting enough pressure on the bearings themselves?
Again grasping for straws but is it possible that the aluminum in the frame has worn to some point?

Anything is possible including slightly stripped steering tube threads, so while you're in there check the threads too:)

Good luck bro!
RC

You say you've tried tapered bearings and gone back to balls. I'm not sure why.

With everything you've tried, this is probably not it:
When I put a RC51 front end on mine, I noticed that the bearings are not compatible, but almost. I think the Super Hawk balls were a little smaller and as I recall, the triple clamp insert without forcing the bearing into the race. The RC51 bearings would interfere.

Make sure you have a compatible set of inner and outer races and bearings. The tapered bearings should have taken care of it, so who knows?

I didn't see this mentioned anywhere - are you sure that your forks are straight? Ok, so the overall frame is just 1% off but maybe the tubes are both bent the same. This is kind of a stretch, but worth asking anyway.

I'm guessing the answer is they are ok, so......

I'm putting my money on the the bearing race bores in the steering head being egg-shaped. 85,000 miles huh? If it's anything like a typical VTR that means about 50,000 wheelies which means about 50,000 landings. You also say that it's been crashed a couple of times. The frames don't have to bend to get damaged. I'd pull the bearing races and measure them really closely with a set of ID mics (not calipers, that's not going to be good enough). If they are out of round more than .0003-.0004in then I'd say that's your problem.

do you have spacers inside the fork tubes? are you using stock length springs? is it possible you are feeling something INSIDE the fork when unloading the suspension?

I'd think he would have a heck of a handling issue if it was that way. The clunking would be his forks bottoming out and the front end washing out!

I wonder if my problem is related. I've had an issue with slop during very slow braking, where the front end will shake. Feels like slop in the steering head bearings, and is getting more noticeable with time. 30K miles here.

I meant the other way - worn springs, shortened, overcome with spacers or increased ride sag. So when he unloads the suspension the spring spacer becomes free and bounces around.

Mick, where are your forks riding in the stroke? Do you have a tie-wrap on the forks? The reason I ask is that with the inverted Showas, once you take them apart to change valving you pretty much have to destroy the oil lock piston. Most of the time the forks are set up properly in that they won't bottom out (proper air gap and damping characteristics) if you're going that far. Possibly are you bottoming out? How about top-out springs? Are they installed or modified?

Okay, now that I'm done with the technical shit, let's move on to some stuff that hasn't been accounted for or mentioned yet, though is highly likely to wear over 85k miles AND is attached to the forks. Hmmm, how about levers? Are they tight or have the bushings worn and allowing them to flop around? Are the bar ends tight? Sometimes the bolt can be tight but the bar end itself is loose. Is the horn solidly attached to the lower triple? And lastly are all the cables and brake lines long enough and have enough play to account for full travel of the forks?

That's it buddy. I've shot my proverbial wad on ideas here. Once you get it figured out let us know what you find.

Hey Mick, did you figure out the problem yet? I'm just thinking that with all the mods you have, is it possible that your forks are not able to fully extend without being interrupted by cables/brake lines or other. if you hit a pot hole, your forks could compress fully, but when they recover/rebound maybe something is preventing them from full rebound stroke. you might jack up the front, losen anything tight and see if the forks can extend more.
also, you might want to remove your fork caps, pull the spacers and springs out and check thing out. it's easy to do a visual.

things like this can drive you nuts. i had an 84 autocar(semi) that I did most of the work on and sometimes, to save my sanity, had to resort to the strategy of letting it go figuring that time and use will make it worse and usually highlite the cause so that it is easier to identify.

thanks, nathan