I have a 03 kfx80 that will only start when its up on the rear wheels.
Once started I can put front wheels on ground and it will idle and drive perfect.
I have no idea what to do
I have cleaned the carb atleast a dozen times
I installed new petcock
cleaned air filter
fresh gas
new battery
150 psi compression
I can not figure out what to do since it runs great and idles fine just cant get it to start normal.
Im willing to try anything

 

I'm trying to think of why.
I feel it must be dumping fuel out of the carb when standing up. This would be like choking it.
Have you tried to hand choke it? (2 fingers in front of the carb)
It has to be something with fuel delivery..or it would seem.

 

I have tried hand choking and it does starts usually rite away.
Also if you are sitting on quad and shake it pretty hard it will also start most of the time.
I agree it seems like its not getting fuel, but the float bowl always has gas when you drain it.
Maybe I can find someone local and try a different carb?

 

update- just pulled carb off again and used toothpaste to polish the float needle and seat.
Pulled reeds out again also cleaned.
Installed new fuel line from petcock to carb
put everything back together prime the carb and hand choke the intake get it started put intake back on carb while running. take it for a 5 minute cruise around yard. The quad is running great, shut it off and try to pull start and YES IT STARTS..
I let the bike settle for 2 hours and try to pull start and to my SURPRISE it turns over firt try. shut off and try again samething starts.
Not sure what changed but Im glad it is now working.
Thanks lt80 for your suggestions

 

Toothpaste on the needle and seat?........I bet the exhaust is minty fresh..lol
I usually use a fine steel wool to polish parts, not quite as messy.

 

toothpaste is a cheap polish, its the baking soda that helps to polish things.

 

Q:: That machine smells good! Is that Klotz your running?

A::: No..Colgate

 

update so its been about a week since i last tried to start the quad.
YUP you guessed it doesnt start unless I stand it on the rear wheels
I ordered a carb rebuild kit and Im hoping this will fix the issue

 

I think you need a carb.
You may want to look up into the main jet. I've had the o-ring that's under the main jet smoosh and close it off.
You're not using the black rubber deal that goes below the jets are you? I throw those away. They can smoosh and cause problems.

 

update installed carb rebuild kit did not help
I was not able to get the throttle screw out (idle adjustment)
Is there any trick to getting it out?