float height problem

driving the bike today (85 xj700N) i encountered a problem after driving the bike for about 10 mins it sounded like it dropped a cyclinder no.1 or 2 wasnt sure and it actually stalled this all happened about 5 houses from mine (luckily) so i pushed it home and checked and drained the float bowls.

all had fuel in them accept no.1 it was bone dry?? i recently put on a brand new petcock and fuel filter so i switched the tap to prime and waited a few then checked the level of the floats with clear hose (see pic 1) all where o.k even no.1 so i took it out again only ran it for about 5 mins then came back and checked the float levels again this time all where o.k accept no.1 the level was low (see pic 2) and iam assuming that if i would have driven it for 5 more mins it would have emptied and dropped a cyclinder again.

what could it be?? does the float height need adjusting ? is there another problem? if the float height need adjusting can someone explain how.

 

I would say you have a sticking float needle valve in #1. If it was me, I would pull the bowl off that carb and check/clean the needle valve. Blow some carb cleaner up through the passageway to make sure there isnt any crap in there causing it to stop flowing, put it back together and re-check. If it still does it, then time for a new needle valve.

Just my .02 worth..

 

says in manual float height 16.0 + - 1.0 mm (0.630+-0.039 in) this might as well be written in chinesse not understanding , float height 16 mm from where to where??????

 

Sticky valve my friend. Pull it and the seat and replace them.

 

I don't set mine that way but I believe it is from the bottom of the carb body to the top of the float with the bowl off and the float hanging down. Best way is the way your pics show. It is the only way to know where the fuel level actually is.