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Discussion Starter #1
In my lurking days, before finally finding my Bonnie and joining the Rat, I read somewhere about resetting the forks/yolks if the front end felt a little harsh. It went something along the lines of loosten all the clamps, pump the forks up and down, then reclamp in a particular order. Bu99ered if I can find it now though. Do any of you have details please?
 

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Discussion Starter #4
What weight oil is in your forks?
Hi Bob,

I used Motorex 7.5W. Research suggests that with my 200lb/6ft onboard this should be a little too soft but whilst a lot better than before, the front end still feels hard and a little harsh over bumps. I wonder if by changing the oil for a lighter weight than standard, I am making up for another issue.

I definitely read a post (somewhere) that detailed a process to resettle the forks by unclamping the yolks, pumping the forks a few times and tightening the yolks back up.

Cheers,
Ian
 

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Hi Bob,

I used Motorex 7.5W. Research suggests that with my 200lb/6ft onboard this should be a little too soft but whilst a lot better than before, the front end still feels hard and a little harsh over bumps. I wonder if by changing the oil for a lighter weight than standard, I am making up for another issue.

I definitely read a post (somewhere) that detailed a process to resettle the forks by unclamping the yolks, pumping the forks a few times and tightening the yolks back up.

Cheers,
Ian
I think I may have posted something on here but it was relating to the lower forks and wheel spindle, I was told after tightening the spindle you should bounce the folks up and down without using the front brake to let the Forks self align as one side is normally free to move on the spindle, then tighten up the fork pinch bolts afterwards.
I'm not aware of anything similar with the yokes as that would only be rotational misalignment and the two halves of the fork are normally free to rotate against each other anyway.
You have nothing to lose by just slackening the pinch bolts, no need to loosen the spindle, then maybe pull gently back and forth on the bottom of that fork leg, there should be some slight movement, then bounce forks up and down without pressing the brake and tighten the pinch bolts. If you don't have the correct torque wrench be careful when tightening as it's easy to to strip the threads or damage the bottom of the forks.
 

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Roll the front tire up against a wall. Loosen cap nuts and pinch bolts. Astride the bike, forcefully apply upper body weight in line with the forks. I usually don't get much movement of the tubes in the yokes, but it may equalize the length to the axle. With a single disc applied this may apply the force unevenly. Bob
 

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Discussion Starter #7
Thanks Chaps,
Just to check; is that axel and both top/bottom clamps? Is there no risk, when I pump down my weight on the bars, of the forks pushing way up through the lot as the yolks slide down them? ?
I guess in my case I should also slackened off the fork brace too.
Cheers,
Ian
 

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Discussion Starter #9
Thanks Chaps!

Ok, I found the article and it echoes your advice. I admit this was an RTFM moment as it was not in a previous post as I re-found it in the manual:

FORK ACTION STIFF
Likely cause: Fork legs twisted in yolks or forks bent.

1. Slacken off wheel spindle clamps, top and bottom yolk clamps, fork top nuts (may require handlebars to be moved) and fork brace (if fitted).

2. Pump forks up and down several times.

3. Retighten from the bottom up (axel clamps, brace, bottom yolk, top yolk then top nuts) to the correct torque.

4. Check to see if forks are parallel. If not, either the forks or yolks are bent (the latter not uncommon on single front disc bikes)

I have a couple of questions please:

1. Why do the top nuts need loosening? They only retain the spring and act solely upon the fork tops. They should not impede and fork movement.

2. Once all clamps on the forks are loose and I climb aboard to start pumping up and down on the handlebars, what is to stop the bike / yolks sliding down and me getting some stantion dentistry?

Cheers
Ian
 

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Hi Ian,
If you are worried that the fork will jamb when the slider is pushed up the sanction, it seems of very little value to attempt to set the fork alignment up while the slider is forced to the tip of the stanchion by the spring. It is much better to lock everything into position while the slider is pushed all of the way up the stanchion, however this is almost impossible to do with the forks fully assembled as trying to overcome the spring pressure is difficult.
I have had good success with this method.
Slacken all clamps and nuts so they are just in contact, except the top clamps.
Place a jack under the front of the engine and support the bike.
Remove the top nuts and springs, and fork oil if you are changing it.
Lower the bike gently with the jack so that the sliders are fully pushed up the stanchions.
Check the yokes (triple trees) are in line, and then tighten the bolts and clamps, starting at the wheel spindle and working upwards.
Raise the bike up with the jack, so the forks are fully extended.
Lift the wheel/fork assembly, and drop it down several times, any tightness or binding can easily be felt as you have no spring pressure to overcome.
If you are happy replace the springs, fork oil and top nuts.

If you had been suffering from a harsh fork, the best thing to do is match the spring rate to the weight on the front wheel when you are riding, this is the fundamental base line of Suspension tuning. The problem we have with our old Meriden Triumphs is you cannot get a spring that is not the standard rate anywhere, therefore when tuning the suspension you are handicapped from the start.

There are a couple of things you can do, oil viscosity, time after time in different threads forum members keep telling us that they have the best results with sae 7.5 oil and Bell Ray is the most popular brand. I would not dismiss this information, it comes from too many respected sources.
Differences in Oil level can have a surprising effect on fork action as it changes the amount of air above the oil that acts like a second progressive spring when the forks are compressed. For a softer fork less oil, for a harder fork more oil, small changes make quite a difference.
Overfilling first and then removing the oil in 10ml steps through the drains is easier than underfilling and trying to top up.
Start at about 230ml (hard ride) then ride, remove 10ml, ride-keep repeating this until you are happy (happier)with your fork action.
If you cannot find a setting you are content with, change the oil for one with a different viscosity and start the process again.
It is better to use the same stretch of road for comparison every time.

Regards
Peg.
 

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Discussion Starter #11
Thanks so much Peg, I really appreciate your replies. I will give this a go at the weekend and report back (as long as it stops raining by then....)
 
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