Cylinder Head Tightening

Information relating to the Matchless G12 or AJS Model 31 650cc twin
Locked
Chessiegolf
Member
Posts: 54
Joined: Fri Dec 29, 2017 8:23 pm
Location: LINCOLNSHIRE UK

Cylinder Head Tightening

Post by Chessiegolf »

Can anyone advise please on what tool I need to reach the cylinder stud nuts.

I have recently got back my 1960 G12 and ridden it 100 miles following an engine overhaul - crank regrind, rebore etc. The heads were supposedly retightened after 50 miles but I've little confidence that was done as I'm pretty sure the tank was not removed to do the job.

The tank is now off but find although I can reach the inner studs using a 3/8" drive, 9/16" socket with an 3" extension, the same socket is too large for the outer holes. Is a special long reach socket required and where can I obtain one?

Also, what should the torque setting be, I can't find that information in the (buff coloured) workshop instruction manual I have.

As an aside, I see there has been a lot of discussion here on the correct head gaskets, mine came as part of a complete set from AMC Classic Spares so hopefully the head gaskets are not from the same (too thin) batch as the earlier Club supply. STL Eng, who did the regrind and rebore advised that the heads should be torqued immediately after the first run, after 50 miles, then 500 miles. I'm keen to not let the heads go any further before retightening but have hit what I'm sure is a minor snag. Any advice would be appreciated.

Thanks
User avatar
dave16mct
Member
Posts: 3234
Joined: Mon Jan 01, 1990 12:00 am
Location: LANCASHIRE UK

Re: Cylinder Head Tightening

Post by dave16mct »

You can get the 3/8 drive socket (1/4 whitworth/5/16 BSF) from our spares scheme. Torque to 22lbs ft.
Dave
Chessiegolf
Member
Posts: 54
Joined: Fri Dec 29, 2017 8:23 pm
Location: LINCOLNSHIRE UK

Re: Cylinder Head Tightening

Post by Chessiegolf »

Thanks for that Dave,

It hadn't occurred to me to look in the tools section of Jampot spares. I see it there now and its described as suitable for the twin head nuts.

Thanks also for the torque setting, much appreciated.
Locked