I have 2007 UC with 50k miles on the bike.

My problem is bike will not start sometimes when its really hot outside. Its seems to only do it when its when its over a 100 degrees. When the the motor is cold its fires right up. I can ride all over town, come home from work let it sit for about 5 minutes. Try to start it, motor turns over but will not fire up. Acts as if its not firing. I have not verified that. I hear fuel pump kick in when I turn switch on. Let it sit about 30 minutes. touch the switch , fires right up. Any suggestions?

 

Anybody? Any thoughts?

 

Texas, the one thing I would try in that situation is hold the throttle wide open when you crank it. If it then starts hot it was probably flooded. With FI that shouldn't happen. My UC is a year older than yours, I've never had a hot start problem.

 

Many have had this problem. There are a few posts if you search. I think the common wisdom is to engage the starter soon after you engage the run switch.

When my bike is hot I don't even wait for the fuel pump to complete its cycle. So far my bike has started easily but I haven't had a day over 95.

Edit: just saw that your bike is a 2007. If you don't have fuel injection the above may not be relevant. If you have a carb, it may be seeping after you shut it off and flooding the cylinders. The post above by Glasspilot is a good check. If you have a carb and it will start with the throttle opened, it's probably flooding.

 

Push the quick disconnect fuel fitting UP into the connector. It will start right up. Guaranteed.(or your money back!) It's vapor lock. Don't know how to fix it other than replace the fitting but i haven't gotten that far yet. I have the EXACT same problem with the exact same bike with 13K on it. Over 95 ambient temp cranks fine no start. leave it for 20 min, starts right up. push the connector up, starts right up. Sometimes you can hear actual vacuum. Tried loosening the gas cap, no go. Something is wrong with the fitting on the tank.

 

If there are still coils on these bikes, a bad coil wire in the winding will separate and it will lose spark. Cooling down lets the winding wire retouch and make a connection. Hot or cold. it should fire right up unless you're missing one key element to combustion.

 

It could be vapor hose with one way valve going to carbon canister plugged up which also common with these bikes.Which will send more fuel to flood the engine especially in heat due to increase pressure, you can locate it under the seat on the primary side right in front of the battery valve is tied with a zip tie to the frame.Disconnect it from top of the valve and try blowing in it see if air passes thru if not use some sort of light lubrication and jiggle it to loosen up.you shouldn't be able suck back the air cause it suppose lock up but should be able blow thru fairly easily.If that is the problem its fairly cheap to replace.My English is not that great hope you understand what I'm saying.

 

I had a bike prior to this one that the fuel in the bowl would evaporate when super hot and would crank till the bowl filled enough for the engine to fire, damnest thing. In fact my wifes Vstar does that too! Dont miss carbed bikes at all.

 

It's a 2007 Ultra. Delphi fuel injection.

 

Vapor lock as said earlier. I usually pull the connector off and then put it back on and the problem goes away.