Head gaskets

Information relating to the Matchless G12 or AJS Model 31 650cc twin
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dave16mct
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Joined: Mon Jan 01, 1990 12:00 am
Location: LANCASHIRE UK

Re: Head gaskets

Post by dave16mct »

A few weeks ago forum member CAB mentioned he had some solid copper head gaskets made at Ferriday Engineering. www.ferriday.co.uk

They will make them any thickness and have his design already (1961 G12CSR). Should be identical to yours.
Dave.
MalcW
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Re: Head gaskets

Post by MalcW »

dave16mct wrote:No but some members put a smear of Wellseal around the oilholes, not too close. I've never done that but you do need to follow a rigid torqueing down proceedure with these. That is a) initial torque down. b) with rocker caps removed run for a few minutes to check oil delivery to rockers. Leave to cool overnight. c) re-torque and go for a short run say 20 miles.Leave to cool overnight. d) Re-torque and run for say 500 miles and re-torque again.
Dave.
OK, that's all done, up to the 20 mile stage. After running for a few minutes, then leaving overnight, all of the bolts took around 1/3 - 1/2 a turn to reach the required torque, but after the 20 mile run hardly any movement was required. Unfortunately, with the height of the cylinders and head on the 650, I have to remove the tank to get the torque wrench and socket in. To get to the rear tank bolt I have to remove the seat, and the rear bolts on that, or rather the nuts and washers, aren't the easiest to get to, though I'm getting quicker with practise. And thinking about it, slackening off a stud and nuts that are integral to holding the frame together, whilst not difficult, just doesn't feel right - or is it just me?

The bike sounded good though.
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robcurrie
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Re: Head gaskets

Post by robcurrie »

I made up a special spanner for the head nuts using a tube spanner. The length worked out perfectly so that I can get to all nuts with the torque wrench without removing the tank. The one end fits the head nuts, the other end I hammered into a hexagon and has a nut pressed in, the outer hex is dressed to fit - in my case - a 17mm 1/2" drive socket.

Rob C
MalcW
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Re: Head gaskets

Post by MalcW »

Hi Rob

Thanks, that's a good idea; I'll see if I can make something up. I currently use a box spanner with one end on the cylinder nut, and a 1/2" drive socket on the other, but the combination is just slightly too long to get under the tank, even if you put the box spanner in place first and then try and get the socket over it.

Malc
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