Sinnis apache 125 only dose 50mph

[Smudgershane]

Hi can anyone help.I have a Sinnis apache 125 and like an idiot i brought a car exhaust whissle thing and tried sticking it over my exhaust.It worked but my dad saw it and went mad as the exhaust gases were trying to get out only through a pin hole of the whissle.He took it off and also noticed my chain was all kinked up through lack of greese and back wheel could hardly turn and bike wouldn't go more than 50mph .Since then we have had new chain and sprockets,head skimmed and valve test,150cc barrel and piston upgrade ,new air filter and exhaust and its no different than before.My dads washed his hands with it now but thinks i might of burnt clutch out but it dont slip through gears,anyone have any ideas pls

[Kizmiaz]

Listen to your dad. It will unbuild itself with you on it.