I am new to the forum and I need some help. I have a Sportsman 450 that is struggling to go up inclines. It does this in high or low gear, 2wd or 4wd. I have seen previous posts about this but no real solutions. My daughter is itching to go out on the trail and I really need to fix the problem. So far this is what I have done:
new primary clutch
new drive belt
carb has been off and cleaned
had plug wire and cut off a 1/2 inch from each end
drained the gas and check and removed the reserve/on/off valve to make sure the screens clean.

the atv runs fine on flat ground. The local guy who works on these things is so far behind in work I won’t see it this summer and there is no dealers close buy. I am told that the fuel pump should not need to be rebuilt and the fuel filter should be fine because it does run fine on flat ground. This problem has been getting progressively worse.

i was told that it could be a possible clutching problem or a bad ground somewhere

Sorry for the long post, but need to fix so I can take my 16yr old out on the trail. Thanks

 

ill give it a shot but need more info.
So explain what it does going up hill.
Do the RPM's stay up as it is slowing down or does it bog down and loose rpm's and speed?

 

the motor bogs down and loses rpm’s and speed and has a hard time making it up hill. The motor will spit and spudder.

 

Sounds like a fuel problem to me but im no expert
The fuel filter could be letting enough fuel through to run fine on flat ground but up hill your using more throttle and the fuel demand goes up and the fuel filter is not letting enough through
The fuel pump could also be going out and not supplying enough fuel for the added demand of going up hill.
I would start with the filter first as its cheap and easy. .
You might also check the line going from the crank case to the pump and make sure it is open and no holes as this will cause the pump to not work properly.
Once you know both of them are good i would look at the fuel pump.

 

Thanks, I am waiting on a fuel pump kit at the moment just to rule that out as well. I pulled the filter off as well and it seems to have no back up just by blowing air through it. I did pull the spark plug cap off the plug and noticed what oil around the top of the plug and in the cap. I was wondering if it is seeping down from the coil which indicates a bad coil. Thanks again I appreciate any info you can give me.

 

Most likely a leaking valve cover gasket or engine blow by tube or the part the tube hooks to and i can not remember the name of the piece the tube hooks to on the valve cover!

 

I thought the same thing at first but the base of the spark plug where it not covered by the plug cap is clean. All the oil build up is inside the cap in between the cap and where it snaps on to the top of the plug. So for what it costs I bought an aftermarket coil, wire, and plug just to rule that out anyways. Any thoughts on a bad ECU unit?

 

Not really familiar with your machine so i don't know the coil arrangement but i suppose it could be breaking down under a load but i doubt it.
I do know when we have problems we tend to over think things and i sure am guilty of that!! to the tune of $650.
I thought i had a bad trans. Replaced and nope not the problem($400). Thought it must be the rear diff($250). Nope was not that. Turns out it was the driven clutch lest i hope so.
Inner sheave bushings are bad in fact so bad the clutch is unusable so had to buy another one. Another $100 and the rebuild kit for it was $75.Waiting for it all to arrive here today and it should fix it finally!
Point is i should have taken it apart first and found out what was actually bad before just ordering parts. Had i taken it apart and found the problem i could have saved lots of time and money.
But dam i still swear it felt exactly like a bad bearing and gears

 

That’s the next step is to rebuild the clutch. Good luck with yours. I hope it works out for ya.