Mixture screw leaking

[Kentish]

Some of you may remember my last thread about a petrol smell. Well today I found that it was still there so I decided to put my finger under each mixture screw hole. I found that cylinder 2 was weepin petrol. This was also the cylinder that was low on vacuum when I balanced my carbs. The thread seems fine as the screw turns in and out easy. Has anyone else had this problem? Could it just be an o-ring? I can't understand why it would leek though.

[Mark YPVS]

sounds like two probs to me, the float needle may be worn or stuck so the carb is over filling and the O ring on the mixture screw is letting by, however the fuel should come out the float bowl overflow first not the screw, the carbs may be a bit blocked? so you may need to strip, clean and replace seals, O rings, float needles etc.
Mark

[Kentish]

Well I done the basics first. I removed the mixture screw and made sue the o-ring was seated correctly. I then turnt the fuel tap off. I then emptied the float bowl and then returned the mixture screw. I then turned the fuel back on started it and let it run for ages. Guess what? No more weeping fuel from the screw!!

You only tear the carbs apart as a last resort mark!! Basics first and if all else fails then so be it..

[Mark YPVS]

as I said you may need to strip the carbs, still dosnt explain why petrol would come out of a mixture screw it should come out over the bottom of the float bowl, glad its sorted 

[Kentish]

as I said you may need to strip the carbs, still dosnt explain why petrol would come out of a mixture screw it should come out over the bottom of the float bowl, glad its sorted 

Yeah I know, Well I have found in the past if some dirt gets wedged in the float valve it can cause it to stick open. Sometimes doing what I did can clear it...Flushing new petrol though it....But then an o-ring thats not been seated on the screw properly could cause it..Oh I dunno....

[Mark YPVS]

ha ha I know what you mean mate, the mix screws look a right pain to adjust ?? might just give mine to PDQ to sort  :lol :lol
Mark

[Kentish]

The left two are easy.. the far right one is easy...the right hand middle one is easier if you remove the starter motor (Only two 8mm bolts)

I use a little screwdriver bit,you know the type that go into the end of screwdriver shaped ratchet? I just get it into position on the screw then remove it and mark it with a little line of say red electrical tape then you know how many turns you have done. Little hands help 

[Mark YPVS]

that's a good tip, will give that a go when I strip it down this summer ( if we get a summer)  :'(

[Kentish]

So I rode the bike today and its still leeking!!! but fear not!!

I then thought to myself it can't be the o-ring on the mixture screw as its new and I replaced it. So On checking the carb rubbers I notice that one of the clamps needed about 10 turns to tightend it!! that was the problem all along fuel was running down and falling in that area under the screw!!!