Racking my brains trying to find the source of the "click"

[riffer]

Hey all.

I've just rebuilt my steering head for the fourth time in a year now.

When I crashed the bike in June it took and almighty hit in the front which pushed the forks back about 10 degrees at least. It caused some ovalisation of the top race socket which I cleared up using loctite 660 quickmetal.

The front end was rebuilt with new races and steering head bearings and lashings of Lithium-based Moly grease.

Since then the bike has been pretty okay except for a slight "click" noise when I put the brakes on.

It's gotten worse lately and I suspected the bottom race socket had some ovalisation in it, as it was shuddering when I put the brakes on. I pulled it the forks off and yep, the bottom race socket fell out with the forks. Checked it out - the race pops in but its a touch loose. No worries, its about a quarter of a mm slack at most, I'll use the quickmetal again.

I left the quickmetal a good 24 hours to set and rebuilt the steering head again. I cleaned out both of the taper roller bearings and inspected the races as well. There are slight wear marks on the races but nothing huge and the bearings seem fine - nice and tight. There is absolutely no movement of the races in the sockets.

I used heaps of moly grease when I put them back in. Torqued the steering head up nice and tight until it was just binding, then backed it off until it moved freely.

I tested the steering head by yanking it back and forwards - no click, nice and smooth - it felt good. Put the front wheel back on, rebuilt the brakes, took the bike off the stand, pumped the brakes until they came on, all good.

I took it for a ride down the road - the steering's great - nice and smooth, no binding in the middle, no roughness from side to sie - it feels lovely.

The only trouble is - there's that bloody "click" when I put the brakes on.

It feels like its coming from the top of the steering head, and all I can think of is that the the stem that comes up from the bottom triple clamp (the one the top triple bolts on to) is not a totally tight fit inside the top taper roller bearing, and that it's moving slightly when I put the brakes on.

I've checked the brakes and they look good - I don't think the pads are moving but I guess its possible. The thing is, it feels like its in the top of the head.

The steering is fine - not too tight- it doesn't feel like you have a pillion on the back leaning from side to side when you ride. It's not binding on movement from centre, just smooth all the way through the turn, and its not loose - I can take my hands off the handlebars at 100 and it tracks straight and true.

Any ideas?

[riffer]

I might also add that I replaced the wheel bearings in June, and also that I have check to see there's no wear in the axle spacer or axle road, and that I put heaps of moly grease in the axle before reassembling it today too.

[scumdog]

Can you 'feel' the movement? can you cause the click by locking on the front brake and trying to move the bike backwards and forwards? and then try it with the brakes off but the wheel blocked front and rear so it can't move?
It might give us an idea if you try the above and let us know.
At the moment I am guessing the plastic metal might not be holdong up to the task of locating the bearing(s). :argh:

[Stevo]

Not sure if I would be so keen myself in using quick metal in something as important as the steering column. My thought was the wheel bearings until you said they were new.

Along the lines of what SD said, Try hopping off the bike and pushing forward then give a decent yank on the anchors. You may need to be quite violent when doing this to simulate the similar forces to do it at road speed. But at least you should be able to see and hear better than having the motor running and doing road speed with the helmet on

[FROSTY]

Bro I gotta ask a stupid question- Are you sure it aint the brake light switch going click as it turns the brake lights on ? Its in that general area and the yamaha ones do make a click as they come on.

[TwoSeven]

Ride the bike forward at about 5km/hr and snap the brake lever in real fast - but not hard so the forks dive.

If you get a click then I'd suggest you are missing either the backing plate from the pads or the shudder plate from the end of the pads.

My pads are an extra mm thicker than they should be so I had to remove the plates. I get the click if I am not smooth on the brakes.

[Motu]

It'll be the steering head - my XT is the same,I can feel no play when it's in the air,it's adjusted correctly and is not tight and has no play (I've had the Fork legs out and done it ok?) I can put my left fingers under the top yoke and feel play when I brake - but it only happens when I am riding around town...in my normal riding I don't notice it at all...and therefore I don't give a toss.

[riffer]

Hmmm.

In response to the previous questions:

1. The Click happens when I go forward and brake. Also when I go over a bump accelerating hard.

2. It's not the brake light switch - too "deep" a sound. Almost a clunk rather than a click.

3. Brakes don't have backing plates.

4. I have tried pushing the steering races around and they appear to be in firm.

Possible conclusions:

a. Steering race at top could be ovalised. Even though it doesn't move in the socket, there's play I can't detect which shows up during braking.

b. The quickmetal could be moving a touch during breaking, causing the bearing to move a bit.

c. The steering head stem could be a touch smaller than the bearing, causing it to move back and forth when the load comes on during braking.

d. The bearings, although pretty new, could be shagged.

e. There could be something up with the brakes, although I doubt it.

[kerryg]

Hmmm.

In response to the previous questions:

1. The Click happens when I go forward and brake. Also when I go over a bump accelerating hard.

2. It's not the brake light switch - too "deep" a sound. Almost a clunk rather than a click.

3. Brakes don't have backing plates.

4. I have tried pushing the steering races around and they appear to be in firm.

Possible conclusions:

a. Steering race at top could be ovalised. Even though it doesn't move in the socket, there's play I can't detect which shows up during braking.

b. The quickmetal could be moving a touch during breaking, causing the bearing to move a bit.

c. The steering head stem could be a touch smaller than the bearing, causing it to move back and forth when the load comes on during braking.

d. The bearings, although pretty new, could be shagged.

e. There could be something up with the brakes, although I doubt it.


You said the sound appears to be coming from the steering head area so probably this is a is a red herring but on the two FZR Yamahas I've recently owned BOTH of them made a clunking noise from the rotors when you first grab the brakes (its because there's a bit of slack in the rivets that fix the rotor to the carrier). It sounds and feels like slack steering head bearings.

[F5 Dave]

Yeah I was going to suggest the rotors & or pads moving. The other thing I was going to suggest is the put your hand on the top clamp & frame as Motu suggests.

With the accident damage it brings another point & quick metal just isn’t going to cut it as it is too 'plastic'. It will deform under load, it is only aluminium fortified epoxy.

Probably better to braze some metal in there (sorry brain fade there, are we talking ally frame? -countrymember) or weld as best can & carefully grind it so the bearings are a tight fit. Additionally the shaft to bearing inner might be a loose fit.

One dreadful night before a trail ride I fitted some new bearings for my KDX only to realise that the bearing was the wrong size for the shaft (but correct for the frame). Out with the shimming metal I luckily had & we got to ride the next day. Err & I might have left it that way :o after checking it a couple of times, no problem.

[riffer]

Okay, I think we have success!

Had a bit of a talk with Frosty about it the other night and I reckon I've sussed the problem.

The steering head works like this: Bottom triple clamp has a taper roller bearing which fits into a race at the bottom of the (alloy) frame. At the top there is another race into which a taper roller bearing fits upside down from the bottom one. On top of that is a metal cap, and then two nuts which you adjust with a C-spanner (special Yamaha part, $120).

So I followed the manual when I put it together and torqued the top C-spanner nut down to 40 ft-lbs. And then I put the other C-spanner nut on top of it and undid the bottom one to 8ft-lbs. The linking washer goes on top of that, and then the triple clamp.

And here's where I've gone wrong. I did not torque the top C-spanner nut down on top of the bottom C-spanner nut. The top C-spanner nut is supposed to be a lock nut to stop the bottom one from moving. So what's happening is that the steering starts out nice and tight but after a few corners its working its way loose.

Pretty bloody obvious now that I think of it, but not at the time, and to be honest, I'm pretty embarrased I didn't think of it earlier.

So, its sorted now and I can go for the warrant without worrying.

That's a good idea about the welding though Dave. My bikes got the first iteration of the Deltabox Alloy frame, and the race sockets are soft, like all the Deltabox frames. I may look into this as it sounds like a good idea for the long term. I will have to see how the quickmetal holds up in the long run.

Cheers for all the ideas people. It's so good to have my bike going better now...

[FROSTY]

And the bill for my consultation fee is in the mail?? :blah: :moon: