HI, I am new here and a new ATV owner of 2 days. To skip the sob story jump to the 2nd paragraph.... I just purchased a 50 acre farm and frankly have no cash. But I needed a way to get around the place, check on animals and fix fences. Without the capital to buy a truck, I decided an ATV would be the way to go. I found one on Craigslist that seem perfect, a 2000 xplorer 400cc 4x4. Spoke with guy on the phone a few times and seemed legit. He brought the ATV around on Wednesday evening and I test rode it for 10 minutes it seemed great. I paid him and he drove off - no sooner had he got to the end of my road - but the ATV lost all power. Full throttle and it barely went forward. I called him, he picked up and did not know what could be causing the issue, said he had not seen this before. He promised to come back this weekend but has not answered his phone Since!!

So, to the issue (which is why you all are here anyway, not hear me crying). The ATV (Can I call it a bike?) starts up just fine, hardly any choke. It idles just fine. After a good 10 minute warm up, it runs great for 10 minutes, then slowly looses all power. It feel like its running on 1/8 throttle - and the revs wont climb, even though the throttle is wide open. If I try ride again after 4 hours, it will run well for maybe 5 minutes, but then it back to bad-*** looking stroller. If left overnight, it will operate well for 20 minutes, then slowly loose power as it heats up. There is a small puddle of gas under (what I assume to be the carb drain Pipe) the engine in the morning.

Any ideas what could be causing this?

Bret

 

Before you do anything else do a compression check when the engine is cold. If it's less than 120psi,then probably when it warms up the cylinder expands and rings loose contact with the cylinder walls and looses power. If so then time for a new bore and over size piston and rings. Plus leaking gas is usually because of a worn needle valve(needle and seat) in the carb.