450es will not go fast, little drive power

[Dfactor 7]

I have a 2000 Honda 450es that was running well last year.  Was pushing snow, nothing too crazy for it, when I noticed it didn’t seem to move as fast.  When I returned home from the driveway I did I noticed I could not go beyond 9mph.  It shifts fine.  Tried without air filter, Cleaned carb, replaced carb, replaced spark plug, changed out gas, added inline filter just in case, new battery, changed rectifier, changed out angle sensor.   I even took off the exhaust n case a nice mouse family decided to try to live in it.  It starts up like normal, will occasionally give a sputter, but similar to how it’s always run for me. Any suggestions, let me know.  

[jeepwm69 7,611]

Have you tried adjusting your clutches?   Changed the oil recently, and if so, what kind of oil did you use?

[ATC4ever 1,079]

Is it revving out good? When were the valves last adjusted?

[_Wilson_™ 6,567]

Does it seem like its more the engine or the drive train ? 

 

[Dfactor 7]

@jeepwm69 I changed the oil last fall.  I don’t really use it much except to plow and to occasionally pull a cart on hunting land.  I used GN4 10w-40 SJ and changed the filter.  I have not adjusted the clutches.

 

@ATC4everit revs okay.  It does seems like it’s slow, like it’s not sparking fast enough.  After changing the plug, I will check it and it seems fouled pretty quickly.  That’s why I tried doing more electrical.  It seems like it’s not sparking enough maybe.  It will choked under heavy load, like if it was pulling something heavier.

 

@_Wilson_™

I feel likes it’s not sparking enough.  I do not have stuff to check compression, I imagine it has a decent amount because I can drive it down the road, shifting electronically just fine to 5th gear.

 

[shadetree 5,869]

2 hours ago, Dfactor said:

@jeepwm69 I changed the oil last fall.  I don’t really use it much except to plow and to occasionally pull a cart on hunting land.  I used GN4 10w-40 SJ and changed the filter.  I have not adjusted the clutches.

 

@ATC4everit revs okay.  It does seems like it’s slow, like it’s not sparking fast enough.  After changing the plug, I will check it and it seems fouled pretty quickly.  That’s why I tried doing more electrical.  It seems like it’s not sparking enough maybe.  It will choked under heavy load, like if it was pulling something heavier.

 

@_Wilson_™

I feel likes it’s not sparking enough.  I do not have stuff to check compression, I imagine it has a decent amount because I can drive it down the road, shifting electronically just fine to 5th gear.

 

have a look at the choke enrichment valve, and choke cable. the enrichment valve may be stuck in the carb, and not re-seating back down like it should.

[AKATV 822]

Just a thought-

I had a similar issue where mine would not rev up, and fall on face when you blipped the throttle

My rubber boot on carb slide was pinched under the top cover during reassembly

The carb is a CV carb and uses air pressure/vacuum to lift the slide

so make sure rubber boot is not pinched/torn under top carb cover

It helps to put a bit of white lithium grease around edge to help seal

You can also remove airbox and watch slide through carb boot to see what its doing

-AKATV