Today while riding around my home my low mileage mint Rubicon ran perfect up until I had to cross a fallen tree that I got high-centered on that shook the Rubicon pretty hard as I freed it from the tree. After that it instantly began to misfire and as seen I the video below- it still runs great at speed but simply will not run at lower speeds. Knowsalot or hondamechanic your thoughts? Its acting like its lean, but once im up to speed runs just great. Super strange!

 

WAG?
Trash in the carb got dislodged during the shake and plugged something in the idle/low-speed circuit. Once over that RPM range, the engine gets enough fuel to run...though probably lean.

You can try draining the bowl and look for junk. One other cheap way to get trash out sometimes is to rev the engine and then block the air intake under the filter with something that won't get sucked in the engine ( like your hand ) until it dies. The extra vacuum load will sometimes pull junk out. If that don't work, time to clean the carb.

 

May have got something in the vent line hanging down from the carb its runs below the frame sometimes or could pinched line when got hung up...Just an ideal this will cause an lean mixture type running,also can make atv run out of fuel because not venting.....Snow could have got that vent line.....Nice Rubicon

 

You could be right Papa as it does act like its got a stuck float, and does run normal if let sit for a while- Im rather inexperienced in the CV carb world, its so strange that at the same exact throttle (1/4 throttle) will misfire when starting out but not once up to say, 10mph at the same RPM. Does thing carb still use the standard:
idle = pilot jet & pilot screw
1/16 throttle is pilot jet and starting in the needle?
1/16th on up to half needle jet?
1/2 to full throttle main jet?

 

Idle to 1/4 throttle slow jet,1/4 to 3/4 needle jet, 3/4 full main jet....Also you said misfires!!!!! does your rubicon have brake lights???I think so...you want to check to see if switch got stuck or frozen up during your snow ride or handlebar brake switches or lever or foot pedal stuck.....

 

Assuming the Rubi is a US model, it does have a front brake lever switch for the start in gear feature.

It's been over a decade now, so the memories are fuzzy, but i believe it does do something to limit throttle if you start in gear...but i don't know if that fits your symptoms. The switch is pretty easy to unplug if need be.

 

I am leaning heavily on the carb venting and will check that out on my next day off. As for the handle bar switch, yup- know all about that, it flat out stops the rubicon! here is a video from 2003 when I first discovered and fixed the stuck switch- here is a really old video taken with a Nokia 6620 back in 2003:

 

That's a 2001! It looks brand new. Was it sitting and forgotten in a crate somewhere?

 

Ok, snow is all gone- 2 vents on the top are clear and the bottom vent by the recoil housing is clear, runs the same as the first video- only starts acting up at lower RPM, runs clean and higher RPM- will misfire at any throttle passion if at a lower RPM including IDLE- float bowl cannot be staved for fuel as it will run great all day long if the RPM is kept up, so- im still scratching my head on this one! Maybe a sticking vacuum controlled slide? Im no expert in these CV carbs

 

You don't mention cleaning the carb out. As DGNAZ wrote, this is the most likely cause of problems.