Is it just my thread pitch gauge?

[Smorgasbord]

I have always taken for granted that the thread pitch was 0.8mm so when setting valve lash I have used the 1/8 turn method.
Where did I get the 0.8mm from? When actually measured the pitch is closer to 0.75mm per turn, provided my gauge is O.K.
That would translate to a 0.09 lash or so.
To get the 0.1mm lash I'd have to turn the screw back 50 degrees instead of 45 degrees.
But it could also be my thread pitch gauge.

But, honestly, how many have actually measured the pitch?

 

[JoeUSA]

The 04 parts Manual claims the nut is 0.75mm pitch.

Regards,

Joe

 

[Smorgasbord]

If that is true then all Husabergs set with the 1/8 turn method run with 0.09mm lash and the Katoom rfs use the 1/6 turn method wich translates not to a 0.12mm lash as they think but to 0.125mm.
The difference is 0.035mm! Why?

 

[JoeUSA]

I don't know anything about the KTM!

I have always set my 2000 501 intakes at 0.003-0.004" (tight 0.004") and exhausts at 0.004-0.005" (tight 0.005") except for a period of experimentation, and have never had problems. No tuliped valves or sunken seats, just a broken intake valve spring at 347.4 hours.

Regards,

Joe

 

[BundyBear]

You'd be doing well to pick the difference between 0.09375mm & 0.10mm with a feeler gauge anyway, especially down in the hole the valves are in!