My plolaris predator 500 won't start on the life of me, I had it running good out with my buddy came back and won't start today i went through the whole thing, tons of spark, cleaned out carb getting gas, we also tried starter fluid and there was nothing, timming chain is very tight and vavles seem fine. and has compression. HELP ASAP.

 

What clearance do you have on the intake and exhaust valves and what do you read on compression?

 

ill look but i drove it all day perfect day before than next day started a little rough than ran inside for a min came back out and wont start...

 

Has to have spark,fuel,air supply,compression and you say you have two of these. Don't discount some trash in the carb,but if it won't start with starter fluid which is way lighter than gas,then I'd recheck the valve clearance and compression. Plus another check is to do a leak down test if you have access to the gauges.

 

Ill test it when i can but what is a good compression rate test and the thing ran perfect the other day **** loads of power would pop wheelies and it sat inside over night and thats when it started to be dumb.

 

Compression should be between 80-95 psi on average because of the decompression device on the cams. Valve clearance shows to be .006 on the intake valves and .010 on the exhaust valves. If tight or loose different shims have to be installed under the buckets. If you don't have this manual,it's worth the 5 bucks!2004 Polaris Predator 500 Service Manual PDF Download

 

Alright ill let you know what i read, this all happened over night too btw. and how i test for leakage?

 

You can get 4 stroke leak down testers cheap at Harbor Freight,Northern Tools,ebay,etc. Handy tool to have if you plan to work on engines. Can easily diagnose engine conditions that compression tests alone can't do. Video is on a simple lawn mower engine,but the procedure is the same for cycles and atv engines .

 

So i got 60 psi on the reader i held the throttle wide open and cranked it over 4-6 times and it stopped a little over 60 each time. but never smokes or anything it does gurgle and bit and pop in the exhaust, and u put ur hand on the back of the carb it sucks ur hand in, maybe intake vavles are out of spec or something?

 

Recheck the valve clearance. Specs show .006 for intake,.010 for exhaust valve clearance. If too tight(especially on the softer intake valves)this could be your problem. You have some wiggle room,so if it shows at least a snug .005 on intake and close to spec on exhaust valve clearance, ans still won't srta,might be time for the leak down test as I mentioned earlier. Main problem I had with the Predator was tight valves. Had plenty of them come into the shop not running because of this,but may not be your problem.