Shocks and chainguard clearance

Information relating to the Matchless G15 or AJS Model 33 750cc twin. This also includes the G15 Mk II and the G15/45
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mdt-son
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Joined: Wed Feb 01, 2012 1:22 pm
Location: Vestland NORWAY

Shocks and chainguard clearance

Post by mdt-son »

Hi all,

I have searched in vain for information on clearance between lower shroud of shock and chainguard for late model bikes, 1964-69. Reason is I consider fitting Ikon shocks which have wider rear springs than Girlings (Ikon offer wide and a narrow series of shocks). A shrouded Girling shock is ø55mm in diameter at the lower end, a similar shrouded NJB shock is ø56 mm. I'd be grateful if someone could tell me the clearance between shroud and chainguard for a bike fitted with shrouded shocks.

Anyone here who has fitted Ikon shocks of any type?

- Knut
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Joker_Bones
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Location: DORSET UK

Re: Shocks and chainguard clearance

Post by Joker_Bones »

If this helps...
This is a '66 G15 with open coil shocks.
The coil is 51.6mm diameter.
With the chain guard central over the chain the gap where the peg is = 4.6mm.
But notice there is 2mm spacer between the bottom eye of the shock and the swinging arm.
IMG_20230517_194141.jpg
IMG_20230517_194352.jpg
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mdt-son
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Posts: 373
Joined: Wed Feb 01, 2012 1:22 pm
Location: Vestland NORWAY

Re: Shocks and chainguard clearance

Post by mdt-son »

Thank you so much, J-B. That's really helpful. You have given me the confidence the Ikon narrow series will provide sufficient clearance.
Nominal clearance is 1.9 mm only when using a 1.5mm spacer (coil is Ø56 mm) but lower spring seat is 34 mm higher up than spring seat at the corresponding Girling shock. We are almost into the radused part of the chainguard. I will post a mock-up picture later.

Your bike looks very nice!

- Knut
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