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Jubilee piston clearance

Submitted by dan_field on Tue, 08/04/2014
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Light Twins

Can anyone tell me what the recommended clearance is for a Jubilee piston, mine is waiting for a rebore.

I should add that they are heptolite pistons and came with no instuctions.

Thanks

Dan

Submitted by patrick_mullen on Tue, 08/04/2014

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Hi Dan,

I don't know the correct clearance. I have had three different Jubilee engines rebored - all years ago-and each time I just supplied barrels and pistons to the engineering shop and left it to their superior knowledge. Any experienced machinist knows to allow more clearance on old aircooled British bikes,

So far I have had no problems with this.

Patrick

Submitted by dan_field on Thu, 10/04/2014

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My engineer is going to do what he normally does but I said I'd check what was specified knowing that the jubilee piston is prone to cracking,

Dan

Submitted by patrick_mullen on Fri, 11/04/2014

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Hi Dan,

Hi Dan,

When you get your engine up and running give good attention to the ignition timing. I was always told that over advanced ignition timing can be fatal to the Jubilee engine. In one respect at least the original points system is better than going electronic as you can time each cylinder independently.

Patrick.

 


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