high lift cam in a quadzilla 300 XLC

[goody111]

I have had a high lift cam fitted to my quadzilla 300 XLC (SMC engine) It has had all neccessary modifications e.g bigger jet in carb, performance exhaust and air filter but it won't run. Can anybody give me any reason as why this is so? I've been told that the cam timing and valve clearances do not have to be altered. How about spark plugs, should these be different as when I turn the engine over it still sparks?
Please help.... DESPERATE!!!

[Tony99]

you have to make sure that the high lift cam can rotate freely, as it may be to large. i also had a simular prob when fitting a high lift cam, all i did was increase the size of the holes where the high lift cam sits. you could file them out or take it to a garage.