hi. im new to these forums and also new to the polaris atv...i have a 2004.5 sportsman 500 ho,when i got the bike it had been out of polaris shop for 2 days from getting motor rebuilt (top end) after about 10 hours of ride time it started making noise and timing chain broke.ive got top end apart and timing chain out of it but was wondering if they sold new chain with master link or do i have to split the case to install new chain? any help would be appreciated....thanks

 

Welcome to the forum! Chain is one piece,NO master links! You have to pull the flywheel and stator plate to gain access to the lower cam chain sprocket. Line the small notch on the lower sprocket with the line on the case(don't move this) slip the chain down through the head and cylinder and align the chain on the lower sprocket. Also you have to remove the tensioner. Cam index pin centers in top center of the head and sprocket slips on,then the rocker arm supports.See if the shop will repair it first!! Plus have them check for any bent valves since the chain broke! A manual is recommended if you do it yourself! If they rebuilt it they should have to stand behind their work!!OPT

 

thanks for your help. the warranty had just run out when it broke...just my luck! i can handle the job just didnt know if it was one piece or not, remembering the old hondas some had master link in timing chain. i already have head and cylinder off just wanted to make sure i had to go deeper in to motor before i started just tearing into it as im waiting on the ordered parts to come in.thanks again......i like this forum stuff that was a quick response!

 

A timing chain breaking on a 500 is a very unusual thing. Check everything over really close because you may have some other problem that caused the chain to break.

 

Also you are almost sure to have bent valves.

 

yea ive checked everything but found everything else is good,the chain is so wore out you can bend it aginst itself(sideways)and it will almost touch itself on the ends. i dont know why they didnt replace it when motor was rebuilt...valves are good ..did a solvent check on them and theres no evidence on valves or piston where they have hit.valves were closed when i pulled head off. thanks for yalls help

 

That thing must have a lot of miles on it or the former owner did not know what an oil change was. These timing chains last almost forever if you run a good quality oil and change it when you should.

 

it was ran real hard,it came with a box of old parts and new parts....3 old cylinders.