Dt125r

[r_colclough]

Hi iv just bought a 2001 dt125r was running mint but didnt realise the cap had come of coolant bottle so it overheated i let it cool down managed to ride it home with more water in but its like after 5-10 mins riding it bogs out but when cold starts first kick, i tried to bodge the cap but blew it straight of sum 1 said to take the full coolent bottle of and plug it but dont no if thats a bad idea any tips or help would be appreciated thanks

[Calum]

Either fault thermostat or head gasket by the sounds of hit.

if you've overheated the engine then it's going to want a light skim on the head and cylinder, then a new head gasket.

[declan]

@r_colclough well it's best just being careful as @Calum says check the barrel replace piston while your there head gasket etc I had the same issue with a brand new top end I cable tied the cap on and rode it for over a year of riding I recently removed the cable tie and it no longer does it

[SpookDog]

Mine pops off if I look at it. The bottles not likely to be the problem. Keep an eye on your temp gauge. Catch it before it over heats. Otherwise you’re gonna score the piston and barrel, and yeah, skinny alloy heads warp for a pastime.
How many miles of good riding did you get before problems?
Also, have you checked your 2 stroke oil?
Not sure if bogging down is a partial seizure? Sure hope not...