@Trumpetsplus said in Looking for Besson Meha piston (Kanstul):
I am still interested in knowing the dimensions.
My tech tells me (my translation: "Your horn has probably had an accident and someone replaced valves 1 and 2. I feel there is too much play in 1 & 2, at 0,05 mm compared to only 0,02 on number 3"
Actually only valve 1 sticks, number 2 seems to work fine.
There is corroborating evidence that there was an accident: when I got the horn off eBay, the bottom valve caps were replaced with heavy caps. But what's more, the threads on the valve casings were dented to the point where one of the caps wouldn't reliably come on and off. I got that fixed by a different local tech, but I only asked him to fix the threads as I hadn't really noticed the sticking yet, then.
Myself I have no idea why the dimension are different. It's certainly possible they were replaced, but I suppose another explanations might be that the casings were damaged and someone did a poor job of straightening them, perhaps including excessive honing/lapping?
Would you happen to know how much play there normally should be in a Kanstul piston?
Would re-plating and re-fitting the pistons be a surefire way to fix this, you think?