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How tight?


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SPENGILLY

 
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How tight?

Sun Mar 05, 2006 10:17 pm » Post: #1 » Download Post

How tight does the nut on the top of the steering head need to be? It's item #6 in the parts manual. What method do you guys use when you snug it up? I used a hammer & screwdriver to get it off.

What about the nut on the top of the triple? I don't see any torque specs.

Thanks.
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Dave Ett
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Re: How tight?

Mon Mar 06, 2006 8:05 am » Post: #2 » Download Post

SPENGILLY wrote:I used a hammer & screwdriver to get it off.


Shocked

That's because it's set by feel. You need to tighten it so that the head races are snug but not tight, and the bars will go lock to lock without sticking, but aren't flopping side to side and there's no play when you try to rock the forks forward and aft.
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Matt@TYGA
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Mon Mar 06, 2006 12:17 pm » Post: #3 » Download Post

What Dave meant to say, but I butted in first, was that after you've set the nut by feel you then tighten the nut up to 2.5 Kg.m as it says in the manual.

If I've just replaced the headstock bearings, here's my procedure:

Fit lower clamp to headstock and spin on the preload nut (the one you're talking about) finger tight.

Flip flop the clamp full lock left and right a couple of times just to check smoothness. Should be smooth.

Now, tighten up the nut while sort of flipping the clamp left and right until you just start to feel it tighten up, then give it a tiny little nip more and flip it lock to lock a couple of times. This helps to square up the bearings.

Loosen off and repeat the above three or four times to be sure the bearings are square.

loosen off for the last time and then tighten up to recommended torque, which is going to be a little tricky unless you've got the special tool.

2.5 kg.m is actually quite tight, but this also serves as a mechanical steering damper of sorts (I was told that by Honda men in Japan so blame them not me).

My bike is not done this tight, as when we were setting up race NSRs what we did was to do it up tight as possible by hand, then just nip it up a bit. That's what Dave was talking about with this "feel" thing. This gives a nice smooth, quick to react front end, but you'll have to pay more attention to the bearings as they'll possibly loosen up within not too long. Using taper roller bearings work better than the stock balls with the "gently nip it up" method.

This is how we set the GP bikes up in Japan, so fear not!

The lock nut should be gently nipped up to the preload nut and the lock washer tabs secured.

If in any doubt, follow Dave's method.

One if the reasons that the headstock bearings can feel loose within a short time after replacement is because they weren't fitted squarely. Following the method above should eliminate this possible problem.
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StephenRC45
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Mon Mar 06, 2006 6:18 pm » Post: #4 » Download Post

On a kinda interesting note, Honda had a recall on some of the 954 Fire blades, what it came down too was they had fitted ball head race bearings top and bottom.

They had so many complaints about head shaking they recalled them all and replaced the top race with taper rollers to act, as matt says, as a mechanical steering damper.

Worth remembering
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Dave Ett
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Tue Mar 07, 2006 7:53 am » Post: #5 » Download Post

Makes you wonder how someone like the Big H can let something like that slip through the net really.
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SPENGILLY

 
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Wed Mar 08, 2006 6:54 am » Post: #6 » Download Post

Matt@TYGA wrote:unless you've got the special tool.

What would that be? What tools do the rest of you guys use, not everybody has the tool collection Matt does. Smile
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gepe

 
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Sat Jan 25, 2014 3:41 pm » Post: #7 » Download Post

No special tool is required.

I used a C-spanner which has a hole at the end of the grip. I attached a digital fish scale to that hole with a cable, put the C-spanner on the adjuster nut and pulled on the scale with 16 kg as perpedicular as possible. As the hole to which the scale is attached is 15 cm away from the centre of the steering stem, I have effectively tightened the adjuster nut with ~ 2.5 kgm.
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