Why so many valve tools for motorcycle engines?

[Stephen Tashiro]

I don't know anything about motocycles or their engines. What I notice when searching the web for parts and tools for the valves of automobile engines is that it's far easier to find such equipment for motorcycle engines. Why is that? Is adjusting valves on motorcycle engines more critical than on automobile engines? Or is it part of the culture of motorcylists to tweak their engines and the valves just happen to be an easy thing to tweak?

[Brett Robson]

On MC's that I've owned in the past, the valve clearance had to be periodically checked and shims installed if the gap was too great.

I'm not sure if current MC engines still require this maintenance or if they've evolved into something more auto-like with fewer or no valve adjustments necessary.

[ray hampton]

It could be because motorcycles are easy to work on compare to cars shoebox motors

[Scott T Smith]

Almost all automotive engines use hydraulic lifters (tappets), which are self adjusting. Almost all motorcycle engines use mechanical tappets, which are not.

The reason why is performance and RPM. Hydraulic tappets typically "pump up" or float at around 6000 rpm. Most motorcycle engines rev beyond 8000 rpm, necessitating mechanical tappets.

Wear between the valve and the seat, on the end of the valve stem, on the cam lobes or tappets mandates periodic valve adjustment in order to maximize performance.

[Dennis Peacock]

There are many motorcycles that no longer require periodic checking / adjusting as they are hydraulic like in a car. However, this is on newer bikes only or specific ones for years back. I have a 2004 VTX1300 and it requires the valves to be checked / adjusted every 8K miles. It NOT that easy to do because so much stuff is in the way and it's tight quarters at best on two of the valves. The danger of dropping a tiny tool into the motor is very high if one isn't very careful.

Overall, it's not that bad, but you need to set aside about 3 hours to do it. All it takes is a .006" feeler gauge, a .012" feeler gauge, a 4mm wrench, and a 10mm wrench and your good to go.