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Discussion Starter #1
I recently purchased a a kfx 450 and in desperate need of some help... basically the bike starts and runs fine but bogs beyond half throttle, I've replaced the FUEL PUMP AND TPS, tps is set correctly, voltage is correct but still bogging.... NED HELP PLEASE.
 

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I recently purchased a a kfx 450 and in desperate need of some help... basically the bike starts and runs fine but bogs beyond half throttle, I've replaced the FUEL PUMP AND TPS, tps is set correctly, voltage is correct but still bogging.... NED HELP PLEASE.
Does it have any mods? Fuel controller?
 

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Checked tps several times, it sits at a steady .64 and 3.79 wide open
0.64v is the problem out of range, 0.62v is the most for a stock ECU...The Procom ECU you can set higher...

TPS range is 0.58~0.62v if beyond will throw you into limp mode & lock your advance timing...!!!!

service manual...
If the main throttle sensor system fails..... """""(the
signal is out of the usable range""""",..... wiring short
or open), the ECU locks ignition timing into the
ignition timing at closed throttle position and
sets the DFI in the D-J method.
Also, the main throttle sensor system and
inlet air pressure sensor fails, the ECU locks
ignition timing into the ignition timing at closed
throttle position and sets the DFI in the α-N
method.
 

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Discussion Starter #8
0.64v is the problem out of range, 0.62v is the most for a stock ECU...The Procom ECU you can set higher...

TPS range is 0.58~0.62v if beyond will throw you into limp mode & lock your advance timing...!!!!

service manual...
If the main throttle sensor system fails..... """""(the
signal is out of the usable range""""",..... wiring short
or open), the ECU locks ignition timing into the
ignition timing at closed throttle position and
sets the DFI in the D-J method.
Also, the main throttle sensor system and
inlet air pressure sensor fails, the ECU locks
ignition timing into the ignition timing at closed
throttle position and sets the DFI in the α-N
method.
Ok thanks, I'm going to adjust the tps and let u know it go
 

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Discussion Starter #9
Well I readjusted the tps to .58 and it did the same thing, then adjust it to .62 with a slight better pick up but still bog at half to full throttle. Could it be anything else? The plug is new, tps is new, fuel pump is new, fuel is clean, the injector was spraying good the last time I tested it, However I'm not sure about the (MAP PRESSURE SENSOR). i assume it's working properly.
 

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I have no clue other than a guess that I would look into the spark plug wire and ignition coil. I'm interested in what you find though.
 

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Did you try cleaning the throttle body, maybe it sat for a while without being started. Just something else I'd look into.
 

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Discussion Starter #12
I have no clue other than a guess that I would look into the spark plug wire and ignition coil. I'm interested in what you find though.
Those are on my list to change as well because I'm not sure what's causing the problem but I'll definitely give u an update when I get it fixed... thanks for the help with the tps tho.
 

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Discussion Starter #13
Did you try cleaning the throttle body, maybe it sat for a while without being started. Just something else I'd look into.
I took the throttle body off yesterday and check it all the way through...it's working good
 

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I took the throttle body off yesterday and check it all the way through...it's working good
Make sure the battery is fully charged...12.8 v standard...

You might want to check the valve clearance...

Valve Clearance: between cam and valve lifter
Standard:
Exhaust 0.17 ∼ 0.22 mm (0.0067 ∼ 0.0087 in.)
Inlet 0.10 ∼ 0.15 mm (0.0039 ∼ 0.0059 in.)
If the valve clearance is not within the specified range,
adjust it.
 
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