Why Do Motorcycles Need Valve Adjustments? What is Wearing Out?

Valve adjustment is a crucial service for motorcycles as it prevents wear on the valve seat and face in the combustion chamber, and neglecting it leads to accelerated wear, compression loss, difficulty starting the bike, and eventually requiring a valve job due to extensive wear.

[PMitchell]

This is a much needed video, it is hard to help people wrap their minds around the idea that a clearance would tighten with wear. It seems a bit counterintuitive.

[Messier_M]

I’m currently researching how to do a valve adjustment on my Testastretta Evoluzione engine and found this video. Very great information, thank you for all the great content. 👍🏻

[Crowbar]

It's crazy how expensive it is to have a shop do valve adjustment. I've done it myself in less than an hour with just sockets, hex bits, feelers, and a screwdriver.

[FranBunnyFFXII]

My Harley doesn't need valve adjustments :D
With stock pushrods, my engine doesnt have any valve adjustment requirements. With adjustable pushrods(replacements for doing cam work) They only need to be checked and re adjusted like once every 20~30k miles but can mostly be left alone for 50K miles.

[PMitchell]

Honda's 80's and 90's air cooled inline 4's had hydraulic valve adjustment, it's a good option for anything that doesn't need to rev to the moon.

[luisnavarro]

I’m 20hrs on a 125cc Chinese bike and had to adjust the valves. I turn them out about 1/4 turn each . Until it bearly wiggles. The intake was backfiring and now is fixed

[twilli]

I think my bike needs adjustment. I bought a New fuel pump and carburator. Getting gas and firer but its hard to crank. It turns over but its sound like its trying to lockup. 1995 yamaha Virgo 250

[Dispariabooks]

What causes such a huge disparity between different brands and their service requirements? Triumphs usually go over 10, 000 miles before needing a valve job, but Royal Enfield usually say around 3, 000?

[Danegerous]

Around how much can we expect to pay for a valve adjustment?

[fallinginthedp]

It's cheap to avoid a valve check job. It's very expensive when your valve burns and your engine blows up.

[HighGrade_FireBlade]

Contrary to popular belief, you can’t hear when you need a valve adjustment. And if the human ear was even capable of discerning the difference between an in spec valve and an out of spec valve, 99% of the time valve lash tightens, so if it were possible for us to hear, we’d actually hear the valve train getting quieter, not louder.