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1967 a65 oil pump worm gear nut
#808934 05/14/20 5:53 pm
Joined: May 2014
Posts: 37
qbeanie Offline OP
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I am having an issue removing the nut. The transmission is in gear which i thought should prevent the crank from turning when turning on the nut. Did i miss something? Also my whitworth tools are loose on the nut so I'm using a crescent wrench. Yes the thread is left hand. Thx!

Last edited by qbeanie; 05/14/20 5:55 pm.
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Re: 1967 a65 oil pump worm gear nut
qbeanie #808940 05/14/20 6:51 pm
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If I remember correctly, the torque specs on this nut are misquoted in the manual and are way too high (like 60 instead of 20 ft/lbs or something). It may be that the last time it was installed, the wrong value was used.

If you lock the back wheel with the bike in gear, that should keep the motor from turning but there is a lot of movement between the crank nut, through the transmission, and throughout the rear chain. It's best to lock the primary side, or at the pistons (if the top end is off).

Re: 1967 a65 oil pump worm gear nut
qbeanie #808941 05/14/20 7:21 pm
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Thanks. Your correct that the torque value is lower as it broke free without me knowing. Gear is off!

Re: 1967 a65 oil pump worm gear nut
qbeanie #808944 05/14/20 7:38 pm
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As mentioned this is a left-hand thread BSA part no 67-0643, apparently 9/16"-20 CEI.

I would try and find a close-fitting socket to undo it, ideally use a battery-operated impact wrench or try to lock the engine using one of the methods suggested above.


1968 A65 Firebird
1967 B44 Shooting Star
1972 Norton Commando
Re: 1967 a65 oil pump worm gear nut
qbeanie #808950 05/14/20 10:17 pm
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Hi,
The nut hex size is oddball to say the least, 25/32in AF
a rough dodge is to use a 20mm single hexagon socket

John

Re: 1967 a65 oil pump worm gear nut
chaterlea25 #808992 05/15/20 7:25 am
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Originally Posted by chaterlea25
Hi,
The nut hex size is oddball to say the least, 25/32in AF
a rough dodge is to use a 20mm single hexagon socket

John

+1


Now let’s all have a beer beerchug

68’ A65 Lightning “clubman”
71’ A65 823 Thunderbolt (undergoing restoration)
67’ D10 sportsman (undergoing restoration)
68’ D14 trials (undergoing transformation)


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