For those of us that have found a bike sitting for a while, a easy way to clean out the fuel system is to visit you local airport.
What you want to do is to buy 5gal of low lead or 100octane gas for your "lawn mower" or "generator" that has sat for while (no road tax). See the AV gas will NEVER varnish and will actually dissolve any gum or gunk in the lines and carb bowl. Plus at 100octane, it will give you bike a boost!!

Try this for fun, take a coffee cup of 93 and one of the 100 octane gas and toss them on the driveway, the 100 will be gone is under 5 seconds and the car gas will take minutes to evaporate.

 

OK, tried it but my bike worked the same. Maybe if I throw it in a different spot on the driveway?

 

I could not see wasting good gas so I out it in the tank and went for a ride... No really I bought top grade gas at Shell instead of cheap grade Kroger gas, once the bike warmed up it ran so much better. Every cold startup is the same cough and lurch, till it gets warmed up. My choke will not stay put, So I have to keep a hand on it till it starts. I need new plugs also. I also have two covers for my stock air filter one is the typical solid closed ham can and the other looks identical but is open on the bottom. I may switch to the other cover that is fully closed.