Technical Reason Our Valves Are Noisy When Adjusted Right

[IanDMacDonald]

So, the Katana forum is a bunch of cheeky guys (beyond annoying), and the valves being noisy/quiet was brought-up. Guys on their forum claimed when the valves are adjusted, engine should be quiet:

"When properly adjusted, you won't hear the valve lash because of the slight reduction due to heat. As time goes on you will start to hear the lash as it INCREASES. Many have called it a sewing machine noise. You will still hear the valve trane but, not the lash."

I remember reading a few posts (cannot remember the author, Bonz?, Moto?) that described why the bikes sounded like sewing machines when the clearances were correct, and quiet when too tight. Can anyone find that thread?

[natemoen]

Don't know how the katana valve train works but with our the clearances get smaller as the valves wear. That is opposite of most all other valve trains which get wider as the valves wear.

[IanDMacDonald]

Thanks Nate. Somebody here broke it down, and I want to bring that to the other forum.

[TomB]

The drag bike I spanner on is the same as the Katana engine, it has mini rockers/followers with one lobe per two valves, the wear on these is much more than seat wear meaning the valve clearances get bigger.

On the XS motors, as Nate says, the clearances get smaller because seat wear is more than cam lobe/shim wear.

The two types of valve set-ups and therefore wear and clearances are different.