I have a 2003 LT80, 120 PSI compression, soaked carb and installed a new kit, new plug and coil. it starts and will idle all day but as soon as I start giving it throttle it bogs and dies. I raised the back end off of the ground and it accelerates and runs perfect. As soon as it's put back on the ground it stalls and dies when accelerating. I'm stumped... Thank you

 

See if the pipe is plugged.

 

Or your primary/secondary clutch is stuck in high gear...no load the motor can pull the higher gear...with load, not so much...

 

Ok, carb is clean but did you put the rubber thing back on the bottom of the jet area? That thing has been known to crush and block the jets. I leave that out.
or pipe....or clutch maint...

 

Thanks for the replies! I took the exhaust pipe off and flushed it with gasoline. I then tested it without the pipe and it did the same... Yes sir on the o ring under the main it was replaced with a new factory part and it's clear. When I lift it up at the back it starts slow then opens up like it should. I stop the wheels and the second on I can put the back wheels on the ground I give it gas and it bogs and dies. Is there another way to check the secondary clutch? Thanks again

 

I was referring to the rubber thing that connects the jet area to the bottom of the fuel bowl.
But, seeins you mention that o-ring You're sure it didn't squeeze shut when you tightened the main jet?
I think that's what you meant but I want to make sure.
Time for clutch maint.

 

No easy way to check clutch, but your symptoms suggest it's stuck in a high gear...think of a manual shift bike...in neutral you can rev to the moon, put the transmission into 6th and drop the clutch and guess what...it'll stall...


Checking the clutches requires removal of the clutch cover, which can be a pain if you don't have the foot peg mod. Once the cover is off you'll want an impact driver to remove both the primary & secondary. You'll need to remove the 3 screws on the primary to see inside (inside you'll look for hard caked grease and flat rollers). the secondary can be tested all together...just see if you can compress the sheaves and that they return to open without binding.

 

I will remove the plastic thingy thank you LT80, was wondering what the heck it was there for.. Looks like I will do the clutch maintenance is there any suggestions for a kit or parts needed?
Thanks again

 

You will have to get into the clutch's to see what parts are needed. I'd think rollers minimum.
I'm also thinking you will find the rollers/roller plate/variator destroyed from rock hard grease.

 

The clutches are the most overlooked maintenance item on these quads...