Wasn't running right wouldn't idle now no start

[lhunter888755]

I have a lexmoto titan 125 efi fuel injected was running fine until it lost power and wouldn't go above 20 rollers changed as they had flat sports and wouldn't idle now at all when stopped just cut out and needed full throttle to force start up now won't start at all any ideas would be greatly appreciated spark plug been replaced

[GrumpyUnk]

Find the 'no start' checklist on site, and follow the steps it indicates.

Losing power can be caused by overheating, lack of proper fuel supply, a clogged air filter, or lack of lubricant among all the other things. Check fuel, air, oil, and finally spark.
An air filter used on an injected engine generally will slowly lose power as it gets clogged. The O2 sensor will slowly choke off the fuel supply to match however much air can get through the filte until it cannot get enough to run. People wonder why their car starts to slow down... but the sometimes have not maintained their air filter.
tom