KDX 220r jumpy with low ceiling

[TXKDXHTR]

Hey all -

new to the group as i finally got my hands on a KDX. its a bone stock 2004 220r with a non-oem carb (unfortunately). a couple problems i need some wisdom on:

1. bike starts just fine, revs just fine, idles well, gets through the gears fine, but when i get on the gas there is a jump/burst of power then nothing. i know these bikes are mostly low end but there is absolutely no middle or top - even in high gears. were talking top speed in the 20's. i am in the process of draining fuel because i think she is running rich (white smoke on start) - but is there anything else to try? my initial thought is carb jetting and air/idle screws but wanted to check here first.

2. the headlight is dull and dims/lights when riding in response to revs. is there any fix to this or battery i can run inline with the harness to better regulate?

Thanks in advance - glad to be the websites newest member.

[SS109]

1. Yes, go through the carb. What carb do you have? Being non-OEM I'm leaning strongly to this being your issue.

2. This is normal for the KDX as it runs on AC voltage and doesn't put out more than 35 watts at max. Best thing you can do is upgrade the stator.

[TXKDXHTR]

definitely thinking carb is step 1- i appreciate it.

Do you think swapping for a LED headlight would help with the dimming?

[SS109]

Do you think swapping for a LED headlight would help with the dimming?

Only if the LED light says it can be run off of AC voltage and draws less wattage than the stock 25 watt bulb.

[Chuck78]

LED will require an inline rectifier, or else a floated ground off the lighting stator + a regulator rectifier. A battery is DC voltage, never AC voltage, so a regulator rectifier and floated ground off the stator are absolutely required then.

[Chuck78]

white smoke on startup has nothing to do with the state of tune of the carb, more to do with oil separating and laying in the bottom of the fuel tank as well as an engine that is not at operating temperature yet.

your carb is absolutely starving for fuel based on your symptoms, although it also could be too rich at low throttle openings. Float height is most likely the first major issue to resolve. It runs low on fuel in the fuel bowl very quickly, that's why you have a burst of power and then nothing, falling on it's face.

[Chuck78]

#1 solution would always be to put on a proper carb, stock or aftermarket genuine Keihin PWK35 Air Striker, Lectron Billetron Pro Series, etc. Even a standard 34mm Lectron or a 1st generation non-Pro Lectron Billetron will be excellent when tuned properly per strict adherence to Lectron's setup instructions.