[Thoven4]

I took my 06 500 foreman for a ride last winter, i had just fixed a smoking issue from dirty filter. Started perfect, ran good for 10 min, headed to the Bush and I noticed I was loosing power so I gave it more throttle and it eventually quit running. After a few min of trying to get it running I got the loader, tried starting it again in the spring with no luck, it Backfired eventually. Now I’m looking for advice on where to start looking (high km quad)

 

[Holistic]

First, i'd not totally rule out a plugged carb. Did it sit for awhile before you fixed the smoking issue? i would assume it sat for abit and the gas got stale and ended up plugging your carb jets. 2nd, Check your valve clearance, If its high km, and they hadn't been adjusted from the factory, that could also be an issue.

 

[Thoven4]

I’ll look into the plugged carb, but I dumped the gas before I fixed the smoking issue, it only sat for a week before it quit running
I was thinking timing chain problem

 

[Holistic]

I’ll look into the plugged carb, but I dumped the gas before I fixed the smoking issue, it only sat for a week before it quit running
I was thinking timing chain problem

Timing chain is a really good possibility. What's odd is that you said it started fine, but loses power when you give it gas. I'd be surprised it started at all with timing chain possibly being advanced or retarded by a couple teeth. But, i wouldn't rule anything out. It doesn't take much to plug a carb.

 

[Thoven4]

My theory is it jumped a tooth, but I’ll check the timing

 

[Holistic]

Sounds good man, hopefully you get it sorted out! best of luck!