piaggio zip 50 2t not starting help!!!

hi i have a 2004 piaggio zip 2t one time i was riding and the exhaust started popping then it bogged and stopped and ever since then it hasnt ran properly, every now and again it will start run for a few seconds then die, wether i rev it or not, i have checked air filter cleaned carb, its getting spark and fuel so idk what it could be i have also tried dropping the jet back down because i recently went up 4 jet sizes, HELP!!!

 

You may want to run a compression test ( no not sticking your finger into the sparkplug hole ) if your low on compression that could be a tell tail sign the piston rings have failed or the piston/barrel are in a bad way.

popping could also be a sign of bad timing ie to far advanced or retarded so you may need to pull of the right had air fan case and check the T marking in the magneto lines up with the marking on the engine case when the piston is nearly top dead center.

see that little black box bolted just above the spining magneto thats called a pickup , on your magneto you will see a little raised pad, grab your credit card and turn the magneto until that little raised pad is right under that pickup sensor, now slide your credit card into the gap between the pickup and the raised bump, it should just about slip in. ( if it does thats all fine the gapping is around the sweet spot).

can you also enlighten us to why you went four sizes up on the main jet please ( to much fuel can also damage a motor )

 

thanks very much mate and i went up four because i had a sports exhaust and removed the air restrictor and it was running a bit lean for quite a while and my friend had a spare jet which was 4 sizes bigger so i thought id just experiment

 

also ill let you know how i get on

 

if you were running lean for quite some time, there is the possibility the top end has gone buddy, so 100% compression test.

as a rule of thumb you upjet by 10% - 15% max , you start high and work down slowly in jet sizes one at a time to find the best one that gives good preformance and still keeps you a little on the rich side.

your not racing so you should always air on having that fuel mix a little rich to keep you in the safe

 

its got like 3 bar compression? seems low, and also i checked fuel was flowing through pipe right because its almost like the carb float bowl cant fill up to meet the demand of the jets because sometimes it starts runs a bit rough the will just bog out?

 

that compression is very low for a 50cc it should be up in the 100psi range.

i would remove the exhaust and grab a good torch remove the sparkplug to. remove the variator case and have a helpful hand rotate the vairator ( front plate) round so you can see the piston travel past the exhaust port up and down check to see if the rings are intact and the piston skirts are not really black. when the piston is at its lowest point shine torch so you can see the cylinder wall it should be nice and shiney no dull area or any scratches / big gouges .

if your able to remove the head and cylinder to inspect them and to check you have not thrown a ring or two or the rings have failed.

your engine is an airpump if its gotta leak its not going to work or run very rough at that. DO NOT try and start scooter if you have low compression theres a chance you could do more damage cranking it over if the rings/piston have failed.

But to me with only 3bar reading on the cylinder compression test your top end has gone and maybe needs replacing.