How is the valve rocker clearance adjusted?
Can't see any way of doing it with rocker box tops off.
Do you simply adjust the tappets to 3 thou and hope the clearance is ok,or adjust the gap on the rocker arms to 10 and 12 thou from the tappets and live with whatever gap the tappets are?
Advice appreciated, Terry.
See service sheet 604.
Jim
Quote from: Jim S on 09 Oct, 2025, 18:37 See service sheet 604.
Jim
Wouldn't download on my phone.
It is quite old.My daughter has given me an I phone,but I don't know how to use it yet.
Ylou dont adjust valve clearance at the rockers. Take off the small plate at the bottom of the push rod tunnel. You adjust there.Very fiddly.You need the 3 thou clearance between the push rod and the cam follower.
When you measure the clearance, gently push the pushrod up so that there's no slack at the top end; just use a screwdriver to do this. If you don't you may get a tappety noise when running because the weight of the pushrod has given you a false reading. This tip is not in service sheet 604.
Get someone to help you print Service Sheet 604. BSA invested a lot of time ad effort in the Service sheets and we are very lucky to have them. My belief is that it was because they were also an arms contractor and were in the habit of producing proper technical manuals.
When setting tappets you should have the 3 thou and 4 and 5 open. 3 should slide nicely, 5 should not go in and if 4 goes but is stiff that's OK.
See this pic from the manual.