I have the 3DS tenere version. Hear stories that they are very weak on the mixture because of design especially for Switserland (altitude and emissions) and therefore bead starters.
Is it a good idea to enrich a bit, and if so, how.
Also, there is a strange apparatus under the tank, I suppose has something to do with emissions because it has two rubber hoses to the carburettor. Is it a carbon filter for the float chamber aeration? Can I do without?

Auke

yes, the switzerland version of tenere 3AJ has different valve size. the german 3AJ has the sizes 46/160/118 (idle/primary/secondary). but take care, maybe the air-valves are also different, this i don't know. refer also to this: http://www.xt600.de/xt_technisches/%...r/vergaser.htm
(okay, it's in german language, but at least you might learn something from the photos)

what you call a 'strange apparatus' is simply a valve which opens above 1000 m above sea level and gives additional air into the carburettor to prevent enriching of mixture due to low densitiy of air in higher altitudes. it is not recommended to dismount it.
bye
klaus@xt600.de