Gas gas ec 300 2014 problem

[GasGasRider_]

Hi, i have this problem and i do t know what can be i think i somthink about eletric but i dont know. There is new ignition coil and spark plug
https://youtu.be/DVs6sJXzH4w

[Moto7man]

It?s probably an air leak. You need to do a leak down test. Could be leaking at one of the crank seals,intake,head. Not electrical.

[GasGasRider_]

I will see , but this is doing only when the bike is cold and then bike work normaly

[Moto7man]

Originally Posted by GasGasRider_

I will see , but this is doing only when the bike is cold and then bike work normaly

There still is an air leak. When your engine warms up the air leak may stop because the engine components expand.This means that you still need to find the leak and fix it. This could be because of old crank seals are failing because after you start the engine the crank seals or head gasket/base gaskets expand enough to seal.At cold start up, your engine is running lean because of the air leak and you may have a piston seizure.

[Doc Brown]

Could also be an earth problem. Check the main power cables from and to the battery and the starter relay.

[5valve]

Also sparkplug cable could be dropping sparks to the frame instead to the plug. Found that on mine incidentaly during night riding and seeing small flashes under tank...similar behaviour.