Posts
247
Joined
1/23/2018
Location
CA
NextGen
9/5/2018 5:45am
9/5/2018 5:45am
Edited Date/Time
11/21/2020 12:06am
I was wondering if it was normal that my 2019 yz250f back fires if you go from wide open throttle to engine braking and that it back fires same thing jumping. currently running the hard hitting map(Yamaha provides this tune stock) that is in the app also have the TP map load on map 2 they both make the bike back fire bike has 7hrs on it and as soon as I broke the motor in and went out for my first hard ride it started this back fire situation
also if I run t4 or renegade mx4 bike begins to back fire more under heavy riding
also if I run t4 or renegade mx4 bike begins to back fire more under heavy riding
Paw Paw
The Shop
You will to make or purchase a wiring harness for this adjustment. ( and no, this adjustment is not in the owners manual)
Paw Paw
Paw Paw
For my bike i made a “T” shaped harness that i could plug in between the harness for the TPS. Kawasaki had detailed schematics on where to put each wire. Then i used my multimeter to read and set the voltage. I would think you can do this on your bike. Might just take some guess and check work to get the voltage reading if Yamaha doesnt have schematics in the service manual.
What was the outcome of this?
Thanks!
Then check your WOT TPS reading. In theory it should be 5 volts at WOT, but most will not get that high right from the dealer. Then check the voltage change from closed to WOT and make sure the change is smooth through the stroke. If reading wanders or jerks as the throttle is opened the TPS is faulty.
Remember that the TPS tells the computer how to adjust the fuel delivery either more or less fuel based on the throttle opening. A pop in the exhaust on deceleration indicates a lean. The TPS adjustment can help solve this.
Paw Paw
Paw Paw
Fwiw the voltage doesn’t change when I open and close the throttle.
Pit Row
Paw Paw
And then at wide open throttle:
Looks as though the voltage drops, is this something with the newer models? Would I then what the voltage to drop a bit lower to make it richer?
Paw Paw
From there you can read the tps input. Mine was .48v, shifted it to .58 then it moved to .60 when tightening.
I expect it to be a bit too rich but I’d like to see if it removes the popping on decel then maybe adjust it back until it begins to pop again, then I’ll know where the happy place is.
Thanks for your help PawPaw
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