So after putting my '08 Fat Bob back together this past weekend with all my new powder and new shocks I went to start her up and it didn't sound right. So I plugged the battery tender back in and waited an hour till it showed full charge. Pushed it back out of the garage and tried again. this time it sounded like it was trying harder to start but i got a loud pop from the exhaust a bang from somewhere by my right knee and a lil puff of smoke from the air cleaner. I did it one more time and same thing. It definitely doesn't sound good, so I decided not to keep trying in case i was doing more damage. My mechanical knowledge is somewhat limited. I installed my own pipes/air cleaner back when I first got the bike and took apart a bunch of stuff for powder coat, but I don't know how to troubleshoot a problem like this. The only I can hope is that is has something to do with the fact that at the end of the riding season last year i left her with a full tank of gas and never added any fuel stabilizer. ANy help would be greatly appreciated.

 

You may have found your own answer. Drain that filthy stuff that passes for gasoline in the US during the winter and stick some new in. Also charge the battery overnight. Some WD40 on the plug-caps, leads and coil might help too.

 

A month is too long with this new gas with all the additives that don't help in storage.
I at least start the bike through the winter every couple weeks and let it run a bit.
Condesation in the tank hurts even more.
This was the first year I used stabilizer and I try to ride year round but not this year.
Keep the battery tender on all the time. Your battery will last longer.
Clean your plugs too.

 

could be bad gas, but i've not had a problem like this with gas i left in the tank without stabilizer... i always add a little sea foam to the tank before i start it up the first time for the season. what did you have powdered? this may give us more insight as to what you disassembled and where you were last wrenching on the bike...

 

an improperly installed breather tube in air cleaner may be the problem.pull air cleaner and see if it runs

 

The only part I had coated that could effect the engine is the air cleaner cover, but even that I only removed the cover and put it right back on I didn't removed the guts. Gonna try draining the gas and pulling and cleaning the plugs and see if that works. Oh I also had the tank console coated but don't think that would have anything to do with it?

 

I don't have an answer, but I don't think it's "bad gas".

 

Did you pull the plug wires off the coil? They may be plugged in backwards.

 

I don't know if this will help but mine did the same thing. After sitting all winter it didn't sound right and didn't want to start right away. Backfire, puff of smoke from air cleaner, stall. I let it idle for about 10 minutes then got on and rode it. Ran fine, still sounded strange for a while but after about an hour of riding, back to normal. No performance issues when riding even when it didn't sound right. I think it was the gas. I did add stabalizer.

 

That happened to me with my Sporty one year also.

Did you fog the motor in any way before storage? If you did, that fogging agent can cause the bike to run rough for a little while too, but after it burns out, it should be fine - if that's the case.