It's not getting a spark.Although saying that i only come to this conclusion after trying one lead and plug lying against the cylinder head to look for a spark,there wasn't one.But then i thought for the hell of it i would test all the leads with the spark plug stuck in them lying against the engine,only two of the leads gave a spark??and this didn't mean two of the leads were faulty either as i swapped the leads over to the cylinder i was getting a spark and it was fine!So this meant two of the leads weren't getting a spark from the top of the cap?Im renewing the cap,leads and rotor arm.