Category Archives: ATV Repair and Maintenance

96 xpress 300 repeat top end failure

Hello and thank you in advance for any help,this is a great forum with an incredible amount of knowledge. I recently rebuilt the top end of my 96 polairs xpress 300 due to low compression. I sent the cylinder to summit offroad in florida where it was bored .040 over and fitted with a new namura piston and rings. I assembled the engine and disabled oil pump and ran a mixture of 32.1 during break in as instructed by machine shop. The bike ran great but after only about 4-5 hrs of use it died and wouldn’t restart. After performing some basic checks I checked compression and only have 90 psi. Any ideas as to what could have caused such premature failure. I performed the break in procedure as recommended by machine shop as well. Only thing I haven’t checked yet is the crankcase seal, however if the crankcase seal blew out wouldn’t that cause much lower compression than 90 psi?? Again thanks for any help!

2001 Sportsman 500 HO bogs and backfires

Hello, I’m have a hard time solving a power loss problem with my ATV. It starts and idles fine but when you give it gas it bogs and backfires. The more gas you give it the worse it gets. I have replaced the spark plug, fuel pump, carb., gas line filter, air filter, coil wire and plug cap. I have checked the pickup coil and stator to the requirements listed in my repair manual (checked within listed range). None of the above have helped the problem. The ATV was running fine when all at once while I was riding it started to bog and backfire. Could anyone give me some advice as to what I might try.

Thanks
RLS

2001 Sportsman 500 HO bogs and backfires

Hello, I’m have a hard time solving a power loss problem with my ATV. It starts and idles fine but when you give it gas it bogs and backfires. The more gas you give it the worse it gets. I have replaced the spark plug, fuel pump, carb., gas line filter, air filter, coil wire and plug cap. I have checked the pickup coil and stator to the requirements listed in my repair manual (checked within listed range). None of the above have helped the problem. The ATV was running fine when all at once while I was riding it started to bog and backfire. Could anyone give me some advice as to what I might try.

Thanks
RLS

Battery question

Just a quick question.
I have a 2006 Sportsman 500HO EFI.
I went to start it the other day and I needed to jump it with a battery pack.
After it started, I disconnected the battery pack negative lead and the engine died. With the motor running and battery connected, I get 14.5 volts.
Shouldn’t it continue to run even with the battery disconnected?
:thanks: