I've a problem, wife bought a chinese scooter for the middle boy. it went slooooow 5mph up hills

i was asked to make it go faster

so i re jetted it with a larger jet
put on a free flow air filter
drilled out the washer in the rear of the exhaust.

on saturday it fired up well and ran like a dream. he was getting 20mph up hills

this morning it would start but as soon as you twist the throtle the engin caughs and dies

i've spent three hours taling it apart and putting things back but all that happens is it starts, it idles and when you twist the throttle it dies with a backfire through the carb.. there are odd occasions that it revs freely and cleanly but then as it goes to idle it just dies with its usual back fire.

we have not touched the timing or anything to do with the motor and i'm at a loss to understand why it's cutting out.

it ran perfectly on saturday.

Help i'm in the dog house again.

ditch

hi
have you tried the float height

blocked jets ?

thought about the jets as it will iddle using the idle jet. i will take it apart again and have a look.

the float could be sticking.

why would it backfire do you think? it's not a full back fire, but a cough and fuel vapour comes out of the air filter

ditch

De-restriction police operation?

Certainly sounds like blocked main jet/ water in float bowl?
Check the plug too for a carbon bridge

Well it's now 11.30pm just pissed the nebours off starting that little bu~~er up

took the carb to bits totally and cheched every thing, there did not seem to be any blockage but the needle did stick a bit so played with it for a while and it is now slick as anything. put it all back together.

now i've fired it up 4 times and rode it across the garden and it appears to work it's just not the time to rev it fully

i will get the lad up early, before i leave 6am and get him to take it for a set run.

many thanks lads, you confirmed what i has been suspecting and now it's alright.

need to go to bed and see if the wife is still giving me the cold shoulder

ditch

Just in case the problem comes back I'd be looking at fuel contamination - something like water in the fuel as this will slosh about giving an intermittent starvation.
Empty the tank - outdoors - and flush out with neat petrol but be aware fumes are highly volatile so be very careful.
Cheers, Pewe