Backside Method Question (valve lash)
 

I'm checking my valve lash via the "backside method" for the first time and would like some advice from those who use it.

The procedure is .0025" GO and .003" NO GO . . . well, my first two sets measure out at .003" GO and .004" NO GO (might be .0035 but I don't have this feeler) . . . so at the most, they are .001" too loose . . . based upon my past experience with Ducatis (both air and water cooled) this would be well within the factory range to leave alone (make no adjustment) which I am inclined to do here (if they were too tight I would probably adjust) . . . what do you think about this? In my experience, valve lash usually decreases with time as the valve face wears into the seat (thus decreasing the distance between the stem and adjuster) so I think these would be fine to leave alone. Other opinions?

You are correct that they are safe. If they are noisy you can get them a little quieter by tightening the up to spec.

-Andy

I just do it the way the factory recommends....Once the crank is in the right position, it just takes a few minutes to loosen the lock-nut, back off the adjuster and slide the feeler gauge in. I've done m/c's on a regular basis since about 1966, so lots of practice for me.

Why would you make adjustments if they were not necessary? Not trying to be a smartass, just curious . . .

I think because it's easy and perhaps he's a little bit of a perfectionist and wants it to be as close to specs as possible. Yes, your measurements are safe (be sure to check all the valves and not just two...) but some just like to know they're bang on. Plus, it may be a bit quieter.

Well, good question: As you know, it's kinda a tight fit to get a feeler gauge in there and most I have done have always been on the tight side.....So, instead of fighting 2 or 3 sizes to see what the spec is, it's quicker to back off the adjust screw and know it's done right.....Just my preference....