Can't run after warm up

[nzemke]

So when you first turn her over she runs great. no hang, no pops, no stuttering, she just works and works really well.

Once it warms up..about 7 to 8 minutes into riding she starts chugging and cutting out then she starts to back fire and won't go above 2k and then finally sputters out and dies...then it takes an hour to cool down then it fires up again like nothing happened.

I am so confused by this...any suggestions for where to look? I already changed the needle valves so that it would run leaner because it seemed to have to much gas...I also went through and fixed one of my float levels that was causing a little extra gas to run over. Any suggestions at all would be greatly appreciated?

[3Phase]

The time to sit/cool off seems a little long but with the running time it could be a plugged fuel filler cap vent.

The next time it happens, open the cap and listen for a hissing sound as air rushes into the tank.

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[FANNING507]

I've had similar problems before. My coils were the source of the problem once, they worked fine while cool, then intermittently when warmed up. The second was the old fuse block, looked fine, but when warmed up conductivity was retarded. The multi-meter is the only way to check both. Some very good threads on checking those out. The pick up wire could also be a common problem with your year of ride. Lots of threads on that one. Hope this helps.

[TopCatGr58]

Hey there,

As has been alluded to, sounds ELECTRICAL more than fuel related.

Get your multimeter out and handy, start the bike, run it till it misbehaves.

Your bike has the Ballast Resistor....which controls the voltage to the spark plug coils, and it gets hot during use. IF it's cracked, it can cause a loss of power thru it which causes a loss of power to the coils. It's under the left side of the gas tank, top of engine....has a 2 wire plug going to it. Unplug it and check IT for resistance...should be only ~1.5 ohms, but will be a little higher due to heat, but if it's much higher or even OPEN....showing unable to measure resistance....but NOT 0.0 ohms....then you will have probably found the culprit.

Next, you can then make a jumper and plug the HARNESS end wires together, and see if the bike will start/run. IF so...again this helps confirm that the ballast resistor is faulty. But don't run the bike very long this way, otherwise you can burn up both your coils and your ignition box(TCI).

HOWEVER, if the ballast resistor measures normal ohms, and jumping the connector doesn't start the bike, then you will need to advance to the actual spark plug coils. Again use the Ohmeter and test the primary resistance, again should be about 1.5 ohms. Also check the secondary resistance.....with OEM plug caps will be around 25K ohms...remove the caps and should be around 15 kohms +/-10%. Values way beyond these could indicate damaged coils. Would be good to have done these measurements BEFORE starting the bike as well so you'll have COLD values for comparison.

T.C.

[3Phase]

... As has been alluded to, sounds ELECTRICAL more than fuel related.

Yebbut I always do the electrical stuff, I'm hoping it's a simple problem that can be checked by riding, then turning a key and doesn't involve meters or wires.

.

[ViperRon]

It is either 1 of 2 conditions causing the condition either not getting electrical spark or not getting 3enough gas. The typical reason for not getting gas is Vapor lock usually the tank vent but it could be a hose with a kink or routing of hoses where an air bubble forms it could be you having the float levels way too low but usually it will not run even cold with this.

With electrical it can be anything in the path. The way to troubleshoot is identify which cylinders have a problem. Most of the electrical path is divided into 2 paths for the firing. It may even be something simple like the battery if the water is low or its old it could heat up but you should notice poor starting. Check your voltage.

Other things can also cause the issue like bad wire to ignition fuse could warm up and every vibration cause an issue. The kill switch could have rust and moisture in it and intermittent but you must do as Topcat suggested take a meter and track it down.

Now be careful on these bikes some times you have multiple issues and you pull a wire or take something loose and that problem goes away or possibly another one happens. Do one thing at a time!

[nzemke]

Well I think I figured it out. So start I hate to admit it but I dropped her the other day...I have a pesky issue where the front brake seizes up randomly after sitting for a little bit. Some times after riding for a little while then letting it sit it goes from soft to stiff. well it happened to be one of those times...and I thought I had put the kick stand back out all the way...and when I finished bleeding the brakes,(is it sad that I carry a 8mm wrench when I ride?) I stood up and I must have rocked it just a little to much and the kickstand popped up...and the bike fell down it didn't do much damage except busting off the ball on the grip for the shifter, and putting a 3 inch across dent in my gas tank

I digress....now as I have been trying to figure this stupid thing out it dawned on me that if I wanted to check the exhaust all I needed to do was shoot some starter fluid on it and I would know pretty quick if I have issues...and sadly I do...I tried to tighten them down but alas I believe that I must have damaged the ring on the exhaust when she hit the ground. I'll find out in another week and a half if that is the fix!

[mack]

Easy things

I always check the easy stuff before I get too involved. It could be electrical, but the as 3 phase said, it could also be the gas cap vent is plugged. It's the easiest thing to rule out so why not check it first.
I always double up on the exhaust gaskets. Torque down range is reduced so the chances of snapping off a stud while trying to seal off a leak is eliminated.