This started at the end of last year and I thought it was just an issue with the cold. (Living in North Dakota) The bike starts up great and runs/sounds good until it warms up and then the idle gets lower and lower until it stalls out. It spits a little fuel out the exhaust so I don't think there is any issue with it getting fuel.

I'm thinking it is an ignition coil issue so I pulled them off and tested resistance between the coils. The manual says it's suppose to be between 2.5 and 3.1 ohms but both of the coils registered at 3.7 - 3.8. I didn't think this what a huge difference so I put the bike back together and warmed it up until it stalled out and quick took it apart to check the coils and they were both around 3.9 - 4.0 ohms. So I'm still thinking it could be the coils but not sure if ~1 ohm is enough to make them fail, wanted another opinion I guess. The spark plugs are kinda black so I know it's running rich and they were wet with fuel when I pulled them after warming it up. That's another reason I think it's ignition and not fuel related.

Last fall I had to jump it with a car battery and my friend hooked up the terminal backwards on the car so they were backwards on the bike.. So I'm wondering if that has something to do with frying something... just not sure what?

Kinda long... sorry... any opinions/help would be appreciated.

 

I don't think your problem is electrical but fuel/carburetion related. If you get spark, it shouldn't change with engine temp. Your engine will want a leaner A/F mixture as the head warms up and may stall if you give it an overly rich mixture. If you're running that rich, it will have trouble keeping idle. Spiting fuel out the rear is not good!

I'd pull the carbs, clean them, blow apart all the passageways, inspect the floats and check and adjust your pilot screws. I think 2.5 turns out from seated is stock for a 49 state f2, 2.75 for a CA model. I wouldn't be surprised if those were significantly too rich. Also, make sure all the jets are fully seated. That should solve most of your problems.

Out of curiosity, did you leave it sitting without running it or draining the bowls for more than a week or 2? That can clog passageways and give you carb problems.

 

It started last fall and I was probably riding it at least twice a week, the temperature was probably in the upper 30's or 40's at this time so I wasn't riding everyday, but then I went to start it and the battery wasn't strong enough to get it to turn over (crappy wall mart battery that came with it) so it had to get jumped. That is when the problem started happening. I got a new battery this spring so that is no longer an issue.

I was having carb issues last year even after my friend and I cleaned them, so my friend took it to his uncles garage and got a really good clean job and new gaskets where they needed it. After that the bike ran great.

 

Your issue is definitely a rich mixture. However, the stock fuel settings are as follows:

49-state: 2 1/8 turns out
CA: 2 3/8 turns out

According to Haynes manual.

You may not need to clean your carbs if the bike responds well off idle and idles well. Try adjusting your fuel screws first.

 

Why would it run great for a couple of months after getting the carbs clean and then all of a sudden be too rich?

When I say it "spits" fuel out of the exhaust it doesn't actually spray out the back, you can just see it start to run out on the bottom lip of the muffler. It doesn't do this until it starts to stall out and you keep it running by keeping the RPMs above 2000 rpms.

The reason I think it's an ignition coil issue is that I've read from multiple sources that the coils start to really show their problems once they warm up. So I was wondering if the resistance between the primary coils, 3.8 ohms, was too far off of the specs of being between 2.5 and 3.1. After I started the bike and it stalled out the resistance was up to 4.0 - 4.1~, so they are getting worse the warmer they get.

I suppose I should say the bike has a slip-on, jet kit, and K&N air filter.

 

Temperature can affect fuel mixture settings, for one. Warmer weather calls for leaner mixture, and vice versa. It could also be a combination of a slightly plugged idle circuit and warming weather to help create a problem of a bad idle when the bike is fully warm.

 

and yes 1 ohm in an ignition circuit is enough to cause problems in almost any vehicle

 

I took the carbs off and looked at the jets and they weren't bad but I cleaned them up some anyways. All the air/fuel screws were 2 1/8" out... So I ordered some ignition coils, they should be here later this week and I'll update you guys with what happens.

 

let me know if this solves the problem because i think im having the same problem

 

The new coils didn't fix the problem. I notice my R/R was very hot after it was stalling out, could that be an issue? I'm sure it gets warm since it's electronics at work but it seemed to be warmed then it should have been...