Mudguard bridge piece

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
Big Pete
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Mudguard bridge piece

Post by Big Pete »

Hi im running a 21" off road front wheel with alloy mudguard
. Is it neccessary to run a mudguard brdge piece between the fork legs to act like a brace? Im already using front and rear stays. If so are they anything that can be bought or easily enough made?
Thanks Peter
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cbranni
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Re: Mudguard bridge piece

Post by cbranni »

Club spares list them but it is showing low stock, AMC Classics have stocked them in the past, you may have to fettle to suit.
Part No 014737

Colin
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clanger9
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Re: Mudguard bridge piece

Post by clanger9 »

Yes, you should make a bridge piece - otherwise the front end will feel very floppy.
1989 Moto Morini Dart 350
1993 Ducati 750SS
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clive
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Re: Mudguard bridge piece

Post by clive »

I would certainly want the bridge piece. It braces the sllders and helps make sure they remain correctly spaced. The front and rear stays will only brace the mudguard. The correct brace for an alloy guard has a u shape with holes for the slider bolts, to brace the sliders, and a top piece which rivets to the brace and supports the alloy mudguard.
clive
if it ain't broke don't fix
Mick D
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Re: Mudguard bridge piece

Post by Mick D »

Hi

In my opinion the bridge retains the mudguard in rotation, without it the mudguard could rotate forwards or backwards, and for that reason it should be installed.

It will also provide some torsional rigidity for the sliders, (over and above that from the front wheel spindle).

I don't think it provides much else in terms of rigidity to the fork assembly.

Regards Mick
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clanger9
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Re: Mudguard bridge piece

Post by clanger9 »

You'd be surprised at the difference a strong bridge piece makes to the handling (especially under braking).
It helps reduce the tendency of the forks to "twist" under load, so the bike feels much more stable.

Here's the (very substantial) bridge I fitted to my Lightweight:
IMG_0683.jpg
IMG_1320.jpg
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1989 Moto Morini Dart 350
1993 Ducati 750SS
Big Pete
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Re: Mudguard bridge piece

Post by Big Pete »

Thanks lads great advice as usual.
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ajscomboman
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Re: Mudguard bridge piece

Post by ajscomboman »

Without a bridge fitted you'll experience what is known as fork walk! This is when under braking the forks twist from left to right, especially more so as there is only a drum on the one side. The fitting of a fork brace reduces the effect dramatically. As an experiment try this, wedge the front wheel in between your legs and move the bars left to right and see how much twist you get without a stiff brace. Try the same again with a brace fitted and you'll find the twisting reduces significantly.
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thornebt
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Re: Mudguard bridge piece

Post by thornebt »

Clanger won't have any problems with that mudguard bridge. Lovely job. Did you make it yourself? Cheers. Bruce.
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clanger9
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Re: Mudguard bridge piece

Post by clanger9 »

Thanks! Yes, I made it by bending a suitable piece of steel using a scaffold pole (!) The bend came out lovely - classic bit of metal-bashing. :)
It does steer surprisingly well, so I like to think the brace is helping somehow...
1989 Moto Morini Dart 350
1993 Ducati 750SS
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