doppler s7r parts and tweaking advice,

i have a nrg power lc with a doppler s7r kit polini team 3 exhaust 21mm carb and pm pro street reeds,(polini 9 variator soon) ive been loosing power and currently put it down to wrong jetting, being a 100 jet when cbs witton think a 105 to 110 would be apropriate, but wanted to know where i could get replacement piston rings if i wanted which i cant find or if the athena rings would fit as athena make the bore, i plan on stripping the bore tomorrow to see if the rings were failing as the bike has power for about one lap then slows down, or to see if any scoring has occured, any thoughts?

 

Check your plug to see if its running rich or lean pal or just take a pic and upload it

 

it is hard getting parts for that 70s i was gunna buy one but couldnt find any spare parts incase it blows even asked pedparts and adrenaline pedstop but they cant find anythin

 

yeah its the plugs mate cheers for that i had the problem before but when i checked them they wee a healthy brown? and i got a br9es in there can you get tens?
and thankfully theres no score marks on it atall but i would still like new rings for the future .... pissed.
btw is ur nrg 172 reg as 172? ive been thinking about doing it to my power ....