2010 rmz 450 runs pops, sputters and stalls once warm

I have a 2010 rmz 450, with 35 hours on it. I run sunoco 110 leaded fuel.

The other day I hit the track and bike was running fine, did almost 2 short laps and bike started popping and just stalled with in 3rd gear.  Put it in neutral, kicked a couple times and it fired back up, it would pop and sputter once over a 1/4 throttle and then stall again.  pushed back to the house and let it sit a little. 

 

Kicked over and started right up, but once warm again it started acting up again.

 

Lastnight, I cleaned the sensor in the airbox, checked for lose or worn wires. all look ok.

Started up, when the bike is still cool it revs out just fine, once warm it starts acting up again.  I pulled the Powercommander off and dumped the fuel out, and will test with just 93 pump gas tonight.

 

I don't have the power connector to start metering all my sensors yet, but will probably have to get one now.

 

Any advice is greatly appreciated.

Likely too much resistance in a sensor or wire. Most electrical issues get worse as the bike gets hotter.

mine did the same once. after a lot of trouble shooting, it turned out to be one of the two wires to the fuel pump that was broken under the insulator, so it could not be seen. once found, i was able to solder it back together.

Update: tested with 93 and no power commander, and it still ran good until it got warm.

Since that test I have pulled every connection apart and toned out to the ecm connector. Everything seemed ok wiring wise. I tested any sensors I could without having the12 volt kit. Pulled spark plug, it looked about normal. pulled the fuel pump and tested the wiring and also the pump with a 9 volt battery, and seemed to be fine. Pulled the flywheel cover and checked for any metal or plastic filings. All in all my bike looks like is should run good. Buttoned up all my electricals and used dielectric grease on my connections. Ran it for a slow run up the drive and once again, spit and sputtered once it got heated up. up till that point felt normal.

pull codes from the ecu see if it gives you anything.

Going to head to cernics soon to see if any codes come up.

Well tonight my friend brought his 2013 rmz over and we swapped tanks and pumps, no change. He talked me into swapping spark plugs after that, and that was it!!!!! My plug looked good, but must have a bad electrode up through the ceramic.

All in all, wasn't a bad thing, I know my electricals are good and clean and everything else tests good. So hooked my power commander back up and call cernics tomorrow to get a spark plug.-_-:)

Good deal... at least it was an easy fix and didn't cost you much.

 

Best part is that all your connections are clean and have fresh grease to fend off water/ moisture from ruining them.

Woah woah woah you can run leaded fuel with FI on dirt bikes? Fuel doesn't come in contact with any sensors?

Yep... why not? I've been running Cam 2 110(Sunoco 110 with a different label, so it can be sold at non Sunoco stations) since day one and no issues to speak of. No catalytic converter, no issues. 

Well tonight my friend brought his 2013 rmz over and we swapped tanks and pumps, no change. He talked me into swapping spark plugs after that, and that was it!!!!! My plug looked good, but must have a bad electrode up through the ceramic.

All in all, wasn't a bad thing, I know my electricals are good and clean and everything else tests good. So hooked my power commander back up and call cernics tomorrow to get a spark plug. -_-:)

BTW, did you ever do a plug chop on your old plug to find out what the ceramic insulator looked like? Just kinda curious what the issue with the plug was.

Woah woah woah you can run leaded fuel with FI on dirt bikes? Fuel doesn't come in contact with any sensors?

Most of the VP fuels people are running in bikes are leaded as well...

 

I didn't do a plug chop, if I get some time this weekend I will.  I did make it to the track yesterday, and the bike ran just fine.

Isn't there an O2 sensor that lead will kill? Or at least shorten the life? I read that the sensors weren't even the big issue with leaded fuel in these bikes.. That it ruins the coating on the valves. Idk exactly why it would screw with the valves. Hopefully I get this 08 rmz today. I would like to continue to run 110 but maybe ill have to save it for the other machines

Lead was used to lube valves long before they were as hard is they are now. It won't ruin anything given the strength of the modern materials used. I have never had a sensor issue either.

Edited by BDubb106

There isn't any sensors that would really even be in contact with the lead anyway, unless you added an exhaust temp as sensor. I'm planning on keeping this bike for a while and wanted the extra lubrication from the leaded fuel, more than the performance boost.

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