Ok guys I need help again. So my 2008 1200 sportster won't start. If I take the air filter off and spray some starter fluid in it will eventually start and seems to run fine. After it runs for a while, I turn it off and it won't start back up, just cranks. I hear the fuel pump when I turn the bike on, but the fact that putting the starter fluid in it will start and run. Could it be corrosion on the relays or something else. The bike has 9200 miles on it. Any ideas

 

Do you have any stored codes?
https://www.hdforums.com/forum/sport...des-dtc-s.html

What happens if you open the throttle a LITTLE bit while it cranks?

My stock tune was very rich at startup, if it didn't fire right away it would act like it was flooded. Opening the throttle would help.
It was more pronounced in cooler weather. What do the plugs look like after it cranks but doesn't start? Dry or Wet?

It could be your IAC (Idle Air Controller) is not opening enough. They can get dirty from the oil mist that is fed into the intake from the cylinder heads.

You have two relays, one for the fuel pump, fuel injectors and coil (ignition).
The other is for the Starter.
If you hear the fuel pump and it cranks your relays are working.
They could be intermittent.

 

I haven't checked plugs yet, but opening the throttle doesn't help. Where exactly is the idle air controller? I would like to check that to see if it is dirty. I will check the plugs.

 

The IAC can be seen looking into the throttle body. It opens to allow air past the butterfly to control the idle speed.

It is generally opened more during cranking since the startup mixture is so rich.