Hi Pepe,

what did you change between the first test when the bike didn't go over 120km/h and the second test when it wouldn't run? Engines are pretty simple in that they need air, fuel and spark to work. if they get that then they "work". Yes there can be all sorts of complications but you must have had most of them sort of sorted for the bike to run before so either it is something that you changed or something that is "loose" (like an electrical connection).

So you need to check that the engine can still get air (filters are not blocked - a lot of air must still get into the engine), fuel (there is fuel in the carbs and coming out of the tank), and spark (the spark plug sparks when it is properly earthed). Just remember that a spark plug sets fire to the fuel so if you are checking the spark by eye (outside the motor) that you don't have any fuel vapour nearby (no wet fuel on the engine and in a well ventilated space). Also remember to not touch the spark plug itself (to avoid electrocution).

If this is sounding too confusing I can only recommend that you find a knowledgeable mechanic to help. It sounds like you have a simple problem and they are easy to check for when the bike is there in front of you.

I can only recommend the same specially since this is going on since october 2013!

Other things to check would be if all pulley marks line up with the marks on the engine, the voltage at the coils and carb syncronisation.

Hi Bluey,

interesting reading this thread, but carburettor is same in english as spanish but egg is huevo

nice reading tech spanish

Pepe, Espero que usted tenga problemas pronto ordenados