125-200cc pre mix problem

Gasoline starts to break down after only 2 months,,at 6-8 months its wasted and smells like varnish and if it sits in a carb your guarantee'd to be cleaning it because of the build up it leaves behind..

It may start to break down the minute it's processed into gas, but it stays perfectly usable for a long, long time.
We have long winters, and I never take any precautions in any of my 2 strokes, or summer/race cars. Never have.
Even my generators and and yard tools sit for 8 months of the year with the same gas and always start right up.

I would suspect his problem is due more to evaporation.

I just took the carb off again and there was a little puddle of pre mix on the lip of the inlet rubber and some more in the air box as well

an old fashioned fix was to gas wash it, as in raw gas
two ways the harder but more efficient is to remove the engine and pour a litlle gass in the intake and cycle it, then lean it forward and cycle it to push it out the exhaust
put some gas in cycle it and lay it on it's side with the sparkplug out, cycle it again to push out the gas
or thirdly buy a box of plugs and start it when it quits replace the plug and go again, it will take care of itself sooner than later

You must be one lucky dude or your gas has a different process north of here,,my godfather and brother in law have been with Chevron a total of 6 generations...

Yes,,premo as a kid my dads wash tank was filled with gas at home and at his shop,,gas was the best cleaner for anything engine related,but times have changed,,i tell you Berrymans cause you can't blow your surroundings up,, cleaning with gas is best but you have to be careful where you use it,,not in your home shop without proper ventilation..

I meant inside the cylinder, last time I used gas as a cleaning agent was 74 or 75
inside it breaks the oil down quickly and cheaply

So I cleaned the carb out then put it back together and and then back on the bike and it started first kick and run for a couple of seconds than stopped and would not start again and when I remove the carb I keep finding a puddle of fuel on the inlet manifold rubber which should surely be passing through the reeds instead of gathering there.

you will always find a little gas in the intake, how much are we talking about?
when you say it started, do you mean idled or you had throttle control, such as in you could rev it at will, roughly how many seconds???

Hi the bike will start and idle for a couple of seconds then die on the first kick with a new plug but when put another new plug in and try starting it it won,t start at all. I,m stumped It's got a clean air filter a good spark and fresh fuel

right after it stops, put a plug in the plug wire and see if it still has spark
3 things needed for combustion compression, ignition (spark), fuel
if you have a wet plug right after it stops and puddling it might be ignition, if it's dry you are not getting fuel

Might sound stupid but does your Speedo show any ECU errors?

also i made the mistake of putting too much airfilter oil on my bike....and it was not getting enough air.

arb
I took off the carb, reeds, exhaust and spark plug out and tipped the bike upside down and loads of rank green fuel poured out so I also flushed it out again with neat fuel. I put everything back together expecting it to start only to be disappointed it fired a couple of times but it only seems to fire right at the bottom of the kick. I need to get it going so I can sell it and get a wr 125 and don't really want to pay the local mechanic £90 an hour to fix it.

if green came out you just need to put clean gas in it kick it with the plug out flip it over and repeat till the green is gone