My PRO Is Surging Especially Under Load - Help!

[rugbynitro]

12 PRO 163 stock with 2300 miles. Surges on start up and especially under load and then clears up when riding on the trail or going down hill. When I say surging, I mean it rides fine and then falls on it's face and then powers up again all by itself pretty consistently in a very short span of time.

I have cleaned the power valves but the surging is getting worse.

I need some ideas guys, really appreciate it.

 

[Skeld]

At a certain RPM? Mine is terrible this way between 4700 and 5400 or so. Especially after I first start it, it gets better after it has been run for a bit. Warm start even.

 

[Murph]

Fuel filter ever been changed?

Pick up screens in the tank clogged?

Fuel pump pressure ok?

Fuel rail holding pressure?

That would be my checklist....

 

[gman086]

At a certain RPM? Mine is terrible this way between 4700 and 5400 or so. Especially after I first start it, it gets better after it has been run for a bit. Warm start even.

Same here. It's the temp sensor in the pipe. After a while it gets so coated from oil charring on it that it gets insulated so your ECM doesn't recognize true pipe temp until the motor heat soaks so the motor cuts out in the mids but only during the first 10-20 miles or so. Remove it and clean with fine sandpaper = problem solved. Rugby - after 2300 miles yours is sure to need a cleaning. Also a quart of toluene has worked wonders for cleaning the fuel system/injectors for me. A must do for the first ride of every season if you ask me. If your sled is cutting out completely then I'd look for shorting wires; there's been a few threads about this in the forum.

Have FUN!

G MAN