Burlen are re-making the flame trap/filter.
Couple of layers of gauze they tell me. I have an original on my 1940 enfield and the jetting didn't require altering (after all it's not a proper filter as such)
I use them to keep the rocks out and if you spray some chainoil on it it even filters some dust out of the air,btw the originals were of aluminium...chris
I think that the mesh interupts the flame front from a spitback through the carb,and dissipates the heat within the flame. I guess it is not totally foolproof, but should substantially reduce the risk of your carb/bike catching fire.
In old fashioned coal mines (and newer ones?) a Davey lamp was used that had a very fine metal mesh totally surrounding a flame, that prevented any fire damp (or methane gas) from igniting. Electrical equipment underground in mines had to be enclosed in a sealed container with any gaps being 8 thou or less, as this was taken as being too small for a flame front to pass through. Any ex miners out there in the forum might be able to better explain this than I can.
A flame trap isn't foolproof. (It only traps flames). Look up Davey safety lamp. The principle is fine cold mesh that a flame won't pass through.(usually brass). If it heats up it doesn't work. I know of about at least five bikes that have been seriously damaged by being lit up by a " flame back" My words because backfire is something else. engines that have a "dead" spark are more likely but a little spit back through the carb will do the trick.. Nev
