This is one for Higgy or Gerhard I'm afraid. Most of us have done the Mikuni conversion and no longer have the weber!
I don't have a hose attached to my vapor line.
I don't run a return line either for that matter. Just one line from tank to fuel pump to carb. Goes like stink no problems with it.
I did have some issues with fuel delivery at one point. Turned out to be a dirty and clogged up petcock. Looking inside the fuel tank it looked clean around the base of the petcock but when I took it out I found it to be clogged up with fine rust dust. Cleaned it and the tank too and no dramas since. Change the fuel filter at every service as well.

Cheers

Ok thanks j.

Hi all, well story so far, I've pulled carb and cleaned it all, ran new fuel lines ( no restrictions or kinks) actually ran for a whole 35 Kim's yesterday at average of 100 kph, before it started to misfire and then just dies, pull over let it sit for 20 seconds then away it goes again. But wouldn't rev over 3500 rpm. So today I blocked off return line to tank and ran straight from pump to carby and bugger me it ran for 60 kms without a prob then all of a sudden just dies again, bu this time when i let it sit for 20 seconds it ran perfect at any revs then stops again repeat steps again then reved out fine to get me home.so maybe thinking fuel pump not so good anymore, this bike sat for 4 years only started weekly so possibly pump just doesn't have enough pressure anymore, going to get a new electric pump and try it over next week or so and see how it goes next weekend. Anyone have any thought more than welcome to put their 2 cents in.
Cheers Greg.

you mentioned the breather hose before. Is that completely free ? In the past some members had problems with clogged breather hoses. Underpressure would build up in the tank and the engine would start to have dropouts. If you ride next time and the bike starts to act as you describe try to open the gascap and see if it makes any difference.

G.

http://www.ebay.com.au/itm/271597204960

G'day G, yeah I've blown thru breather pipe and seems clear plenty of air coming from tank.

G'day lane, yeah I'm going to wack on a low flow facet pump.not sure wether to go the 1.5-4 psi or 4-8 psi.

only California spec bikes had a canister the rest had just vent tube(s) which anchored at the front of the swingarm

Thanks higgy

G'day all, well story so far, today I've ridden 90 kms and only 1 back fire no breaking down and just stopping, yesterday only got 15- 20 ks but I tried to start bike after it just stopped no good, opened fuel tank cap let pressure out bang started up straight away and rode like a Trooper.i did two things today 1 st was reverse the fuel tank cap around I thought maybe it was causing vapour lock, 2 nd was take plug off ignition barrel and found wire number 4 think it was its was at least red,had gotten hot and there was corrosion on terminal and inside femal terminal so cleaned up, also I guess there should be a cap on back off wiring which there wasn't so I made my own and now it's water proof. Oh and new fuel pump went 3-4-5 psi solid state pump and I couldn't believe it it fitted perfectly no extra brackets or re drilling. Ill take her for another run tomorrow and see how she goes.

Still going good Greg?

3 things I had to do to my 906 which would randomly shutoff when I first got it

1 the wiring upgrade, I also installed a relay for the headlights to help with the ignition switch melting.

2 repaired the ignition switch and its connections. I found the connector to be backing off and the bike would just die. Would crank but no spark


3 replaced the ignition wires to the plugs


rode the 906 for 2 years after this minor weekend's worth of work without incident

Good result today, cleaned all terminals again, taped up exposed wires at back of switch plug ( yes will be done properly I won't leave tape there ) also taped plug to ignition switch and did 90 ks without a problem. So maybe all these issues were bad condition and when hit certain rev's it was enough to create the breaking down then the loss of power. Also while I had things apart I ran some convoluted tubing from under grab handle for centre stand to a t- piece which points directly at didiplex then one also to reg rectifier, just for a bit of fresh cool air. I notice on one run how hot it was under seat especially. Was a cool ish morning here so ill to out again this arvo in hotter weather to re test..