M8 stalls at 4000 RPM

[jbell2355]

I have a 2011 M8 with no mods and 2500 miles. Yesterday, I rode for about 3 hours during which time it ran fine. Suddenly it bogged down and died. Started first pull, but then would bog when RPMs got up to 4000. Every time it died it started on first pull. I was able to nurse it back home pumping the throttle the whole way trying not to go over 4000 RPM.

I let it sit for an hour, determined a possible diagnosis of a Throttle Safety Sensor and unplugged the sensor. Sled ran fine for 15-20 minutes and then the original problem resumed.

There are no error codes on the display and no other symptoms I can identify. Given that it ran fine for a short while after cooling down, I'm thinking it may be a coolant temp sensor, but I'm wondering if anyone more knowledgeable has any ideas.

Thanks.

First post, btw.

 

[diggerdown]

Get it acting up and unplg the coolant temp sensor, that will tell you right away if that is causing the problem. I doubt that is it but that would eliminate one possiblity. Next you need to find out if it is shutting the spark or fuel off. You can just take one of the wires off a plug and hook another spark plug on the wire and hook a jumper cable to the plug and engine. Hold it with a pair of rubber handle pliers to be on the safe side. Makes it easy to see if it keeps sparking.

 

[jbell2355]

Thanks for the ideas...I'll give that a try.

 

[concretebob]

If your sled is EFI make sure and check the smart valves in the tank.
Bad gas can plug them up.

 

[jbell2355]

Turns out it was a bad stator. Couldn't figure it out myself so I had to bring it in. $800 for a new stator, $600 for one that was taken off a brand new sled. Ick.

 

[WyoBoy1000]

If it is cutting out at 4000 there is only one thing that will cut power at 4000rpm. Its the TSS, throttle safety switch in the throttle block. if your throttle is to tight it will cause this to happen or if the switch is bad.
If the switch is not pressed in the ecu will kill the motor at 4000rpm, its a safety in case the throttle sticks