I recently bought a 1986 BMW K75C and I just replaced the spark plugs, coolant, oil, recharged the battery, and put gas in it. The problem is, that it will now not start. It started right up prior to all of this maintenance work. I tried opening the choke, pulling the clutch lever, etc. It whines like its trying to start, but will never catch. I can hear the fuel being shot into the engine. The spark plugs are the correct ones, with the cap on the end, and gapped correctly. Also, when I twist the throttle, when it's trying to start, it makes a sucking/popping sound, almost like when you twist the cork off of a bottle of wine. The sucking sound is coming from the intake. I tested the spark plugs, and they spark, and all of the electronics work. AAANNNYYYYY HELP AT ALL WILL BE GREATLY APPRECIATED!!!!!!!!! Thank you.