the stater needs to be rewound
1250 CC's.
I would first unhook the kill switch to make sure it is not shorted out. Next I would look at the stator.
NGK CR8EK or NGK CR8EiX (Iridium)
No.
First disconnect your kill switch, if that is not it, check your plug cap, then if that is not it go on to your stator.
The vin number listed above is for a 2001 KTM 50SXR.
4
50:1
Again it depends on which model you are asking about. A 520 SX (4-speed) will top out at around 70 mph depending on the gearing. The six speed 520 EXC will run 100 mph. It's not that the 520 SX is slow its just geared for the track and there's no motocross track that you would you run 80-100 at.
My manuel recommends 40 to 1on my 2001 ktm sx I've never had any problems with it..
KTM recommends Motorex Top Speed 4T 15W50 oil 0.7 L