Okay, here goes. Maybe someone out there can help me with this one. I went out with my 450R today and did some riding. First time out with the Yoshimura exhaust. The day went great, until just before I was going to put it onto the truck. Just pulled off the track, and it stalled on me as I downshifted. Thought nothing of it, and restarted it. Ran fine, until I tried to just touch the thumb throttle, then stalled. Checked gas, plenty in tank. Was quite a distance from the truck, so I tried some more. Noticed that it will not stall if I slowly bring the revs up just a bit, then give it anything from about 3/4 throttle to WOT. Limped it back to the truck in 1st gear, but it was not running right at all. Breaking up and popping and stuff. When it shuts off, it's almost like it's running out of fuel. But it's not. Took the carb off, checked the bowl, and the main and pilot jets, and cleaned them all while I was in there. Does not make it any better. Tried taking the fuel cap off to eliminate vapor lock, but still stalls. Tried tank petcock at all positions and problem still remains. A member of the track I was riding at asked if it has a Throttle Position Sensor, said maybe that is it. I don't know if it has the control to do this or not.
Here's what I have done to it.
Yoshimura Stainless Exhaust Full System
Uni Filter with lid off
DynoJet jetting kit with their needle installed and 175 main jet (per DynoJet instructions with exhaust and no lid), Air/Fuel screw 2-1/2 turns out.
Note, it ran fine all day long and idles okay
Stalling problem just occurs off idle.
Spark plug was black/dry carbon on it, but that could be from the poor running condition.
Anyone out there have a shop manual that may troubleshoot this?
Here's what I have done to it.
Yoshimura Stainless Exhaust Full System
Uni Filter with lid off
DynoJet jetting kit with their needle installed and 175 main jet (per DynoJet instructions with exhaust and no lid), Air/Fuel screw 2-1/2 turns out.
Note, it ran fine all day long and idles okay
Stalling problem just occurs off idle.
Spark plug was black/dry carbon on it, but that could be from the poor running condition.
Anyone out there have a shop manual that may troubleshoot this?