YZ450F 2011 stalling issues

I'm new to Thumper Talk and will apologize in advance if this question has been addressed already. If it has, I simply can't find it.

I'll start by saying that my bike is all stock. I have the GYTR Tuner only. Regardless of how the FI and IG settings are, my bike stalls occasionally when I roll up and stop WITH the clutch in. Anybody else have this problem and/or the solution?

Any advice would be greatly appreciated.

Check your idle speed.  Could be too low. 


If the idle is set too rich in a carbed engine, it will cause just what you describe because a rich idle causes the engine to drop back to idle speed faster than a leaner idle does, and it can drop so quickly that it actually dips below idle speed before it "catches itself" and then it stalls. 


With fuel injection, though, fuel is often cut off entirely in closed throttle coasting conditions until the engine speed gets to be below a set RPM, and unless you know how the fuel program is set up, it's a little hard to diagnose the problem.  The other thing is that the GYT-R tuner, handy as it is for the money, has no ability to trim the idle fuel mixture one way or the other.  Only the scan tool that Yamaha techs have at the dealerships can do that.  But, that still may be worth trying.  You might hop down to the YZ shop and have someone take a look at leaning it just a bit.

Thanks GrayRacer. I'll check out the idle speed first and go from there.

I thought I'd mention how this issue was fixed to help out anyone else who may be having this problem.

It turned out the idle was about 350 RPM's too slow. I plugged in the GYTR Tuner, started the bike, and turned the idle up to 2000 RPM's. No more stalling and it even starts easier.

Thanks again GrayRacer!

Edited by mclean211

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