Banshee with Dellorto PHBG 19mm race carb setup tips ?

[Crash Dummy]

G'day guys. I've got a problem and am looking for some advice before I go any further.
I've just installed a Dellorto 19mm PHBG race carb on my banshee and am having some problems getting it to do much at all.
Just some basic specs on the engine first. An ordinary Banshee 50cc polini rep with squish set at .51mm and ports cleaned up and crankcase matched to one another. Polini reeds and reed block modified to suit and an reed toppers opened up to 23mm (11.5mm each reed). Nothing too special.
The carby fitted to the bike currently has a 60 idle jet, 96 main, W9 needle on the 2nd clip from the bottom (2nd highest posistion possible)
(stock settings for the carby are as above except for the needle posistion which was 2nd from the top (3rd highest posistion) (leaner) and a 75 main jet.
What i'm experiencing is a nice idle but when I go to give it some and get to 1/4 throttle and beyond it'll just die out like it's getting no fuel.
Where to from here ? My tuning options are very limited as the nearest legal place I can do it is Indy. 150KM away.
Any help you guys can provide would be awesome and I'd really appreciate it.
*edit*
Further detail
The idle mix screw is set at 1.8 turns out.
*extra note*
I've ruled out the air filter choking the engine by removing it and giving it some stick. There was no change.
*extra extra note*
I've put the C clip for the needle on the lowest slot now to raise the needle as high as possible. That seemingly hasn't changed anything.

[Hoover]

i had the same problem with my 18mm dell.. and i was advised that it could have a 4 stroke emulsion tube in it....

[RONIN]

Hi Crashdummy Pm sent that mite help you

[Crash Dummy]

I'm just continuing my troubleshooting now.
I'm going to remove the carby overflow catch bottle and tubes and see if it suddenly starts working.

*edit*

Well that didn't help.

[Crash Dummy]

I've rerun my fuel line so it's a full down hill run. I had a small uphill section before by mistake because my line was too long. But that didn't fix the problem
Stripped the carby and cleaned it out completly.
I've now got a 99 main in it
I mean right now if it's been idling for a little bit the thing launches with no mercy, wheelie launch and power for about 3 metres before going BRRRrrrrrrrr and dying.
I'm about to try it again.
My nahbours and family hate me now i think. :oops:

[Crash Dummy]

Well that didn't work either.
I tried having a quick play with the idle air mix screw and screwed it in to richen the mixture and that just made it a whole lot worse. It ended up with no power at all. Screwed it back out and launched okayish before having a cough and dying again.
I'm thinking the idle jet is too big.

[mac90]

first thing first ya will have to work out if its leaning out or flooding & stalling out from 2 much fuel ? (drowning the spark)

another thing to try would be to throw the filter on & choke it a touch, see if it makes any difference

it could be somthing to do with air velocity going past the venturi & large droplets forming or the oppisite & not getting enough flow to draw the fuel up the main jet ?

was it fine before with the reed setup & different carb ?
try the old carb again & make sure its running good & to confirm its the carb or you will end up chasing your tail all day long

[Crash Dummy]

Yeah thats my next plan of attack Mac.
I'll reinstall the stock carby and see how that goes. Maybe I do have another problem. How would I know though The spark plug looks good though but it's hardly an indicator of what's happening in the engine given how little heat I can get into it.
I haven't changed anything on the engine since I last took it out. It felt okay last time I rode it except for feeling a bit weak as if it needed a touch more fuel when the stock carby was installed.

[mac90]

if you remove the plug & pull the engine over right after the stall out you will see excessive fuel spray & vapor blow out of the top end if its stalling from 2 much fuel

& the plug will be mostly dry if its a lean stall

or you can go to the trouble of removing the reed & seeing how wet or dry the crankcase is while doing the carby change
also 2 strokes are a bugger to restart once flooded because of the extra fuel can pool in the crankcase

[beans]

Hey crash.I had simler problem once.Turn fuel on and start bike.Turn engine off and also fuel.Then carfully remove carby and holding level ,remove the bowl and check the fuel level.You might find its way to low.You will have to bend where the needle is to raise the float.Just a thought.Mines was the opposite.To high and runing rich all the time
Cheers
beans