1 1/4 in front fork plastic bush

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1 1/4 in front fork plastic bush

Postby Andy51 » Tue Feb 06, 2018 9:52 pm

Hi All, I have just stripped a pair of '55 on 1 1/4 in forks and the upper plastic bush in the slider was made of white plastic (nylon?) - all those I have seen before on 1 1/8 forks were made of black Bakelite-type material. Were some made of nylon or is this something a PO made? Andy

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Re: 1 1/4 in front fork plastic bush

Postby clive » Tue Feb 06, 2018 10:02 pm

I've only seen black bakelite type material or a sort of bronze metal.
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Re: 1 1/4 in front fork plastic bush

Postby LynP » Wed Feb 07, 2018 7:19 pm

I have seen some 1 1/8" white nylon ones, they might even still be in a box a the back of my garage. They must have been made as an after market replacement years ago.

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Re: 1 1/4 in front fork plastic bush

Postby G15 Roy » Wed Feb 07, 2018 7:57 pm

LynP wrote:I have seen some 1 1/8" white nylon ones, they might even still be in a box a the back of my garage. They must have been made as an after market replacement years ago.


I have seen the same with a Russells lable on, strange what some old dealers stocked and would now say new old stock.
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Re: 1 1/4 in front fork plastic bush

Postby MikeM. » Wed Feb 07, 2018 10:24 pm

One of the problems with nylon is that it expands when it becomes damp or in a moist atmosphere.

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Re: 1 1/4 in front fork plastic bush

Postby vincentvv » Thu Feb 08, 2018 7:09 pm

Indeed Mike, My g80cs from 53 had the white nylons in when I bought it and the front fork was completley stuck. Aparently water drips down your front fork inside the oil seal and so on to your nylon bushes. I used another sort of material wich does not expand when damp... This is the dutch datasheet of the material I used for my bushes: https://eriks.nl/datasheets/815/nl/down ... 00,-groen/

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Vincent!
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Re: 1 1/4 in front fork plastic bush

Postby 56G80S » Fri Feb 09, 2018 9:01 pm

A bit late but mine originally (!) and when I refurbished several years ago were fitted with the "black" (although mine were a bit brownish).

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Re: 1 1/4 in front fork plastic bush

Postby Steve S » Sat Feb 10, 2018 10:39 am

When I stripped my lightweight 1 1/8 in ones they had seized in the white nylon bushes. Club spares supplied black plastic replacements. I have since heard that nylon contracts over time!

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Re: 1 1/4 in front fork plastic bush

Postby MikeM. » Sat Feb 10, 2018 9:39 pm

Nylon expands when it becomes moisturised as it absorbs the moisture. I used to run an injection moulding department in a switch manufacturing company and the parts were made to tight limits, we had problems when using old stock parts that had “grown” and had to dry they out to return them to their original sizes. These problems occurred when the company went over to automatic assembly as the parts wouldn’t fit in the machines. No problems on hand assembly though.

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Re: 1 1/4 in front fork plastic bush

Postby Andy51 » Sat Feb 10, 2018 10:31 pm

Many thanks to all who provided advice. I will replace the nylon bushes with Spares Scheme black plastic or knock up a pair of phosphor bronze ones on the Myford if I can get suitable material at a reasonable price. Cheers, Andy

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