[Antho Po]

Hi guys,

I am coming to ask you for advice because my quad has some trouble starting, it takes a long time to start and when I am in a low engine speed it tends to have a lot of flame return or even it graze a little ...

I changed: the spark plug, oil, air filter, gasoline, I adjusted the valve clearance, I checked the distribution and everything is OK!
I also tested the TDC sensor, the results with the accelerator closed I have 0.62v and throttle fully open I have 3.22v.

Saturday I take him to a professional but I'm afraid he will not find the fault ...
So I turn to the forum to find out if someone has already had the problem?
It is a 2008 KFX450R with an original ecu.

Thank you for your help

 

[Dust Devil]

Hi guys,

I am coming to ask you for advice because my quad has some trouble starting, it takes a long time to start and when I am in a low engine speed it tends to have a lot of flame return or even it graze a little ...

I changed: the spark plug, oil, air filter, gasoline, I adjusted the valve clearance, I checked the distribution and everything is OK!
I also tested the TDC sensor, the results with the accelerator closed I have 0.62v and throttle fully open I have 3.22v.

Saturday I take him to a professional but I'm afraid he will not find the fault ...
So I turn to the forum to find out if someone has already had the problem?
It is a 2008 KFX450R with an original ecu.

Thank you for your help

Welcome to the Forum...

Make sure your battery is fully charged 12.8v standard, before any testing

Your 3.22v @ WOT is out of range...3.7v is the lowest acceptable

Double check your TPS again..
Output Voltage at Sensor
Standard: DC 0.58 ∼ 0.62 V (at idle throttle opening)
DC 3.7 ∼ 4.1 V (at full throttle opening)

Also check your TPS Input voltage, see picture

 

[GotDatGas19]

i had a similar issue and it was shim under tappet was sideways. don’t know how but it happened . that being messed up caused my tps to go. repaired and replaced and was a raped ape.