Low speed slapper

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Rob Frankhamr
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Re: Low speed slapper

Postby Rob Frankhamr » Fri Jun 22, 2018 9:45 am

Thanks for all the replies chaps. The spanner I use isn’t an issue for me size-wise. My onboard toolkit is just a bunch of stuff wrapped in an old t-shirt which lives in the under seat box, no lid. Besides, I can’t imagine ever needing to adjust steering bearings at the roadside so the spanner can stay at home. If memory serves, I used a bloody great socket that cost me more than any socket should when I had the yolk off previously. I seem to remember it fitted both the fork top nuts and the big yolk one. I’ve had the bars off frequently, with no fairing it’s fiddly but not a big job.

Thanks for the nod about my ‘81 bike not needing the c spanner - that explains a lot about why I couldn’t see how or where I’d use one CH was using. Side note: have you seen him recently? He doesn’t look well at all, physically or mentally. Making some odd videos. A few of us owe him a lot. I wish him well.

Therefore (I flatly refuse to start a sentence with ‘so’), plan of action is:

Handlebars out of the way
Remove clamp bolts and tap screwdriver wedges in to hold them open
Remove centre bolt
Try to find where I can use to tap the ... whatever it’s called ... round a bit until the wheel moves side to side smoothly but not back and forth
Everything back together
Then bleed the brakes and clean out the fuel tap filters, just because they’re more jobs that need doing.

Ah well, there’s worse things we could spend our time doing eh.

Jon


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Once you've got the bearings set seemingly satisfactorily, make sure you gently move the steering from side to side several times looking out for tight spots. If there's one, there will normally be two or three.

This is the phenomenon known as brinelling although technically that description only applies if it's caused by overtightening of the head bearings. There are two other causes.

The first is corrosion... on early models, this was made worse by the lack of a ground wire to the forks, which meant that all circuits attached to the steering head grounded through the bearing but it can happen on any machine if the bearings aren't kept greased.

The other is (yes, you guessed), riding the bike with loose head bearings.

In any case, it will happen eventually to all bearings that spend most of their lives in one position like head bearings (the swing arm bearings also suffer from this).

No matter what the cause, I'm afraid the only remedy is to replace the bearings.

Rob
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Jockboxer
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Re: Low speed slapper

Postby Jockboxer » Fri Jun 22, 2018 12:37 pm

I am struggling with why CH thinks the fork tube clamps need to be loosened?
Because as you tighten the adjuster you are very slightly reducing the distance between the top and bottom yoke.....pulling the lower yoke up as you turn the adjuster to remove the excessive clearance.....and given that the fork legs are fixed rigidly to the top yoke, the lower clamps need to be released.

The amount of movement is likely to be tiny but I guess it would introduce significant tension if those clamps were not released.

Mick.
Ah! Thank you master! It all makes sense now! Every day is indeed, a schoolday!

Jon K
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Re: Low speed slapper

Postby Jon K » Sat Jun 23, 2018 9:05 pm

Just a quick update...

Turned out the centre nut was little more than finger tight; must have worked loose somehow, or maybe I just didn’t tighten it properly previously. The bearing did need some tightening too, I’m guessing that too had worked itself loose because the centre nut was.

Anyway, all sorted now so thanks. The forum scores again, like Germany just did in the last few seconds.

I wanted to follow advice and drop the forks to clean and re-grease the bearing but it seemed too complicated - I’ll try to get to that when I’m more in the mood.

Cheers,

Jon.


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Bike - 1981 R100 /7T
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Roy Gavin
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Re: Low speed slapper

Postby Roy Gavin » Mon Jun 25, 2018 5:33 am

The center nut on my G/S slackened off even when the torque was correct - on mine it was a sign that the top plate is stressed out, flexing excessive, approaching fatigue failure and due to be replaced
Yours sounds like it is the same.

Jon K
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Re: Low speed slapper

Postby Jon K » Mon Jun 25, 2018 8:27 am

Thanks Roy. Is ‘top plate’ another name for the top yoke?

How did you find out that was the cause on yours? Did it break?

One thing that surprised me: when I had the centre nut off I looked down the hole and I could see daylight - looking at the exploded drawing in Haynes, I can’t see how that’s possible.

Jon


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Bike - 1981 R100 /7T
Location - Essex, England
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Rob Frankhamr
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Re: Low speed slapper

Postby Rob Frankhamr » Mon Jun 25, 2018 4:24 pm


One thing that surprised me: when I had the centre nut off I looked down the hole and I could see daylight - looking at the exploded drawing in Haynes, I can’t see how that’s possible.

Jon

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The steering stem is hollow and passes right through the bottom yoke so there is a hole right through.

On a R100/7, there should be a steering damper fitted as standard. This has a long rod that passes right through the steering head from top to bottom. At the top there is an adjusting knob. At the bottom, there is a rack and pinion arramgement to adjust the throw of the hydraulic damper. With this in place, you can't see through the hole. Newer models don't have the damper so you can see right through.

It sounds as though someone has removed the damper completely from your machine.

Rob
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Roy Gavin
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Re: Low speed slapper

Postby Roy Gavin » Tue Jun 26, 2018 12:16 am

Jon, what alerted me to the fork problem, apart from the nut slackening off was that I could see the forks flexing when I was moving the bike around the carport.
A SJBMW top yoke and tubular lower from Flatracer , careful set up and they are more rigid than the 41mm items on my Funduro.
Not a bad result as the G/S forks are unbushed and the old girl just clocked 450,000 km.

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Phil_J
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Re: Low speed slapper

Postby Phil_J » Tue Jun 26, 2018 8:49 pm

I when though the same with my 82 RS the michelin were worn but appeared to still have plenty of life left but a new set of tyres and wobble when

Phil
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