cateye engine problem home made scooter please help need advice

hey guys how is everyone i hope this is the right part of the forum .
i have a homemade gas scooter that i whipped one day out of boardem
it has a early cateye pocket bike engine 49cc that i salvaged off hard rubbish years ago now this thing has been getting me around for the last 6 months after the coppers gave me a bright yellow canary on my old falcon and i cant aford to drive so ive been getting around on this it does or was doing 50kph an hour at full WOT wich was mesured with a gps (true no joke)
until i decided to take it for 1 hour long ride wich i held it at WOT the whole way now i am 4 strokeing at about 4 thou rpm where i was geting about 10+ out off it before, i have already replaced the fuel pump diaphram thinking it may have been streched but it made no difference my fuel econamy has gone out the window and i am spitting a fair bit of fuel out tha venturi on the carb i have compreshion checked the cylinder and i am only down by 5 psi after that long ride... is it posible i have worn the rings down? the only other thing i can think of is the coil winding may be breaking up i have already checked for cloged muffler, dead spark plug and compreshion seems fine if any one can give me some ideas on this thing it would be great thanks guys i have included some photos aswell its my 4th build so far and probably my best so far i recently bought a f80 enging kit off ebay and i recon this thing beats it by a mile for performance and quality
here are pics

here is a quick you tube vid off my scooter the build only took about 5 hours
and i am acualy realy blown out at how long this motor has lasted i only expectid it to last about 200k if i was lucky... but 6 months !!! its a great motor
CLIP0002.AVI - YouTube

yeh thanks mate your probably right ... it was a long ride on the dirt i shoul take a closer look .....in the motor and maybe get some crank bearings with the piston kit but i might try the carb kit first and then work from there ....... i just cant see how the botom ant top end can be screewd when ive only lost 5 psi out of the cly compreshion and looking through the exhaust port it looks preety resonable .... i will post my findings for everyone but is it posible the metering diaphram,float needle or spring in the carb can that where out after something like that a good hard long ride??? i would not have thought so!!! but its not driveing a brushcutter its driveing me 80kg with a 49cc motor at 50 kmh ....i supose you can get dud aftermarkit kits for walbro carbs !! but on a riggy didge pocket bike do they re-kit there carbs after each race????? due what i described above....... whould be interesting to know !