Just checking but you do know that a brake lever must be pressed in in order for the electric starter to engage ? Many forget at times . I have heard of Roketas having issues with the fuel cap . If you web search YYQT21A ( my 2T Jonway is also one ) there is a recall on those Jonways with bad fuel and vacuum lines . If you ordered online you may want to go to any auto part store and buy 3/16 ( I think ) fuel line to replace your fuel and vacuum hoses along with fuel filter too . I am lucky my dealer does tweaks like this before selling them after tired of having simple issues if sold stock out of the crate .
Make sure the sparkplug cap is tight on the plug as mine has came off 3 times and I have read where several also have had it happen but it is simple to push it on via the access panel in the front body section between the seat and floorboard . If you have a Torch brand of plug go get a NGK ( THE ONLY BRAND to use ) that many auto part stores carry in case there is no scooter shop in town . I opt for the NGK iridiums after learning about them 25 years ago from a trail riding buddy . They do not make it run faster , but easier starts , does run better , and less likely to get fouled out from oil build up . I use BRP8HIX like many use instead of the 7 model as it is a cooler heat range than the 7 . Make sure to check the intake tube from the airbox to the carb that is does not have any leaks .
When my 2T was 2 months old it has started up with giving only a 1/32nd of a twist of the throttle and sometimes a couple of gentle wang wangs in winter and the enricher would have it idle up for a bit until it warmed up . One night I rode deep into the country and bought gas a shady place instead of a trusted source . It ran perfect all the way home . The next morning it turned over and hit a bit at first but no start even after a few tries . I doubled checked that the fuel tank was full and the oil tank as it has a sensor that may prevent starting or running if the oil level is too low to prevent dry damage . I called my dealer since it was warrantied for advice . They told me another client had the same thing happen to a great running scoot and baffled them as it had spark , compression and fuel but no start . They drained the fuel tank and carb bowl , filled it up with nonethanol ( highly suggested ) and tada it was good again . I bought a manual siphon pump from Harbor Freight and pumped the gas in a spare gas jug as well as used the drain hose on the bowl so it did not get on the ground . Filled it up with nonethanol premium gas and tada mine was running like it had been . Here is a directory of nonethanol gas stations that may be in your area
http://pure-gas.org/ . Always use premium as I had to sign a paper during the PDI to only use premium as it only holds 4 liters so 20 cent extra is no biggy .
Make sure to only use brand name 2T that says safe for injector like Maxxima synthetic blend which I use . NEVER use weedeater junk , wait until you use up the first quart ( was around 600 miles for me ) then you can go with a full synthetic like Bel Ray or Motul 710 . I tried Lucas 2T oil and it sucks . It separated in the carb as when I drained it to remove the bowl to upjet some was clear and some blue ( Lucas usesa blue dye ) .
Mine cam with a 19mm TK carb with a 40 IJ and a 68 MJ . I went with a 75MJ as with a 2T you always want to be a hair rich to avoid a soft seize . Later on I installed a 47mm or 70cc BBK and I always had to give it a sip of throttle or it would want to stall install of idle for a duration . I replaced the 40IJ with a 45IJ and now it starts with no need to give it any throttle and idles great with no stalling