neos goes slower

hello , my dad has a yamaha neos and it used to hit around 80 kmh on flat , and now its only doing about 55-60 kmh , any ideas why or what could be wrong? ive cleaned the air filter and carb... thanks

 

Spark plug okay? Changed 2t oil for diff brand recently?

does it feel like its pulling okay? i have a runner that used to die a death when full throttling letting go and putting it back on, inspected the rollers to find they were all worn and just look tired replaced them and now problem sorted !

 

it pulls okay , but then feels like something s stopping it going faster making it like cut back :/

 

changed the rollers , not them...

 

belt look okay whilst you was in their? does it make any noises that it shouldnt?

 

ye i changed it for the one on my jog r which was new when i got my new kevlar belt and no it dont make no sounds but when i start it and rev it and then let the rever off it still ticks over really high like im holding it down still , but if i turn it off and start it agen it doesnt :/

 

still no idea what it is

 

checked for leaks and stuff around the carb? gaskets etc...sounds carb related posibly

 

okok ill check as soon as possible thanks.