I'm loosing my numeracy mind on valve clearances!!

[McCabe-Thiele (Ted)]

Failing to Plan is Planning to Fail - so whislt I'm messing with my front wheel in the daytime - my mind started to wander into valve clearances come bedtime.

I've looked in the manual - it gives Inlet & Exhuast for a 400 engine as 0.05mm or 0.002 ". I haven't spotted the words Hot or Cold engine anywhere.

My feeler gauges - I have imperial & metric are probably 50 & 30 years old respectively - I can't read any numbers due to deterioration over the decades except on the never used thick ones - note to self buy replacements.

I thought okay I understand 0.002" it's two thousandths of an inch in words - I'm used to bigger gaps like 12 thousandths on a car. So 0.002" is the thickness of some medium grade paper.

Stupidly I then said to myself naaah it's got to be 20 thou surely - then I looked at the decimal and though no 20 thou is actualy 2 hundreths of an inch.

At 0.002" I'm amazed you can hear a tappet rattle at all - its close to naff all as gaps go.

Does this look suitable or will it be too wide ?

https://www.ebay.co.uk/itm/114686642402?hash=item1ab3db48e2:g:UH8AAOSwUylgKybE


 

[smoothoperator]

I'm pretty sure valve clearance applies to cold engine Ted. My old feeler gauges have fortunately kept their markings. I used the method of tightening the adjusters with the 3 thou gauge in, then when you remove the feeler gauge it is actually closest to 2 thou. I've done this on cars and bikes before and found that they tend to get too small a gap when tightened using the actual gap gauge, if this makes sense. Either way I wouldn't buy just a single gauge as you get a better measure of the gap by trying 1 thou up and 1 thou down to "feel" the gap. It does feel weird setting such a small gap.

[Bryanj]

The pitch of the thread on the adjuster is 1mm so 1 full turn is 40 thou 1/8 of a turn is 4 thou

[Oddjob]

To confirm Ted, it's 2 thou cold.

[McCabe-Thiele (Ted)]

Thanks for that Steve, Ken & Bryan.

[royhall]

Ted get yourself some 2 thou shim steel online. You can then cut and bend a piece to suit. Makes the job way easier and you get enough on the length to make about 6.