Greetings,
I tried to reply about an hour ago but my previous draft got lost
Your post lists two faults;
fuel starvation - by this I presume stoppage of petrol getting to the carburettor;switch petrol to on - run the engine until it stops - quickly disconnect the petrol feed pipe at the carb end and check for petrol flow - no flow disconnect the other end from the tap - if flow then pipe faulty if no flow move tap position to check for flow - petrol flows tap needs dismantling - no flow remove filler cap - petrol flows then filler cap vent not working still no flow remove tap from the tank for inspection of filter and internal passages.
I fitted a replacement tap to my Alp 4.0 with a reserve position, the original just has a stupid warning light which you probably would not see even if it was working - mine had been cut out
petrol overflowingthis might be dirt between the flow valve needle and seat; worn float valve; punctured float or incorrect float height
if you have to remove the carb make sure that you thoroughly clean all of the cables and frame of collected dirt first
prepare a clean uncluttered work surface with supply of clean containers - egg boxes/ corrugated paper/plastic microwave takeaway meal type trays; photograph each stage of the dismantling; use only sharp good fitting screwdrivers
take your time and inspect each parts as you remove it such as noting small 'o' ring in diaphragm chamber
inspect the float for petrol gaining access inside the body e.g. punctured
inspect needle valve seat and viton tip for dirt or wear
inspect free movement and float height when inverted under its own weight
The best ultrasonic bath I have used is made by ASNU (
http://www.asnu.com) and sold by ProBike but it is expensive, cheaper alternative is that which is sometimes sold by Aldi.
As to cleaning fluid basically an ultrasonic cleaner is best using simple warm soapy water mixture, you could spray every item with carb/brake cleaner as you strip the parts and after cleaning in the soapy solution. The ultra sound causes cavitation and the bubbles and sound waves do the cleaning without physical damage such as scratching.
Proprietary brake/carb cleaner I use is Jaguar BC41 spray (wear eye protection) but others will do, cleaning fluid can be bought from;
Maplin;
http://www.maplin.co.uk/p/jpl-seaclean- ... e-1l-a75lgMistral;
http://mistralie.co.uk/collections/ultr ... hine-partsProBike;
http://probike.co.ukIf in doubt fit a replacement needle valve whilst the carb is in pieces.
Spray lots of aerosol lube on the inlet stub and air filter connector before refitting the carb, whilst you are at clean the air filter; box and drain tube. I fitted an inline petrol filter into the petrol supply line and fitted extra length breather pipe to loop under the petrol tank out of harms way and water ingress. Lock wire the drain screw so that you do not need to over tighten it and replace screw head bolts with cap screws.
Always run the carb dry after use. Do not store the bike with a full petrol tank, top up the tank with fresh petrol before restarting or going out for the day. Yamaha Marine used to sell a 'fuel stabiliser' but not sure if it is still available.
If you need more info check out previous posts or just ask.
TTFN
Hugh.