[tonyf]

hello, new to this so not sure if this is posted in right place or not? my appologies if it is not.

my atv - 1999 kvf400

my prob, i bought this as a non runner, the engine wants to turn over using both battery and pull cord but doesnt fire up? all i get when i give a bit of throttle is a backfire blowing the carb off the rubber mount from the inlet side of the cylinder.

what i have checked?

Petrol is getting to carb ok, i have drained fuel out of carb.
I am assuming sparkplug must be ok due to backfire?
I have opened top rocker plate cover and checked the rockers are moving at the top end they seem to have movement so are not jammed?
havent checked the exhaust valves thou?
When the carb is off the rubber mount i have placed my hand over the rubber inlet and there is suction when it is turned over.

Question for the guys that know more than me,(which isnt hard) is this likely to be a broken valve? or a timing issue? or something totally different?

If it is a timing issue can i check the valve settings and what should they be?

I am still trying to source a service manual but for this model (looks like i need two a base manual and supplement) no online downloads are avail and i need to make a trip to the dealer, sux really some one needs to make a digital copy of these.

Thanks for your help
Tony