2018 KX450F mapping/running hot

omalley
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omalley
Greetings,
I have an ‘18 KX450F with 6.1 hours. Since day one, it started hard hot (even in neutral), likes to cough and die in tight turns, and runs hot. Really hot. Yesterday in 90-ish temps on a tighter track, I heard pinging off idle under load. I’m running 91 octane pump and the only mod is a PC T-6 with the restrictor tube/screen removed from the end cap. Otherwise stock.
Bike runs great otherwise. I’ve heard these are mapped lean.
Has anyone else run into these issues with this bike? My 09, 11, and 13 KXs ran hot, but always started easily and never ran quite this hot.

Should I be sending my ECU to someone to be remapped? Run higher octane (was thinking of VP T4)?
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kb228
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kb228 7/23/2018 11:18am
7/23/2018 11:18am
I cant help you, but im dealing with similar stuff on my 09. Hard to start hot, runs lean as hell and died on me last weekend when it was 93 out. Mine was mapped by tokyo mods and it doesnt make a difference if i swap a stock ecu for the mapped one.
Paw Paw 271
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Paw Paw 271 7/23/2018 11:49am
7/23/2018 11:49am
Try adjusting the TPS to be a bit richer. Most likely set at about .5 v from factory. You may want to try about .62 volts to make it a bit richer.

Paw Paw
omalley
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omalley 7/23/2018 11:54am
7/23/2018 11:54am
Paw Paw 271 wrote:
Try adjusting the TPS to be a bit richer. Most likely set at about .5 v from factory. You may want to try about .62 volts...
Try adjusting the TPS to be a bit richer. Most likely set at about .5 v from factory. You may want to try about .62 volts to make it a bit richer.

Paw Paw
How is this accomplished? Sorry, my mechanical skills are above average, electrical/EFI not so much...
Paw Paw 271
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Paw Paw 271 7/23/2018 1:18pm
7/23/2018 1:18pm Edited Date/Time 7/23/2018 2:24pm
The TPS is a sensor on the side of the EFI throttle body that adjust the fuel delivery based on your throttle position. It tells the ECM how mush fuel to deliver based on that position. Adjusting it changes that fuel delivery amount from idle to full throttle. The voltage to the TPS is about 5 volts and the TPS alters that to a range of about .5 volts to a full 5 volts and that goes to the ECM. Each additional .1 volt adds fuel to the engine via the injector. It is adjustable, but you must have the proper plug in electrical tools to do so. A good shop can do this for you.

Paw Paw

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omalley
Profile picture for user omalley
Posts
1528
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Snohomish, WA US
omalley 7/23/2018 2:54pm
7/23/2018 2:54pm
Paw Paw 271 wrote:
The TPS is a sensor on the side of the EFI throttle body that adjust the fuel delivery based on your throttle position. It tells the...
The TPS is a sensor on the side of the EFI throttle body that adjust the fuel delivery based on your throttle position. It tells the ECM how mush fuel to deliver based on that position. Adjusting it changes that fuel delivery amount from idle to full throttle. The voltage to the TPS is about 5 volts and the TPS alters that to a range of about .5 volts to a full 5 volts and that goes to the ECM. Each additional .1 volt adds fuel to the engine via the injector. It is adjustable, but you must have the proper plug in electrical tools to do so. A good shop can do this for you.

Paw Paw
Great explanation, thanks. Seems to run well higher up so fixing the bottom might be the ticket.

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