I bought a 01 scrambler 500 (4storke)about a year ago - always noticed a little miss at high rpm. Got worse in the last 2 weeks - found the cam was shot. Replaced the cam checked the valves and timing twice.
Next came a bad idle problem found when i cleaned the carb messed up the settings got that fixed. After all this i drove it fine for about an hour went and parked it and noticed the smoke. White smoke at/around idle speed if you rev it up goes away let off starts to smoke. I had compression of 180 BEFORE i changed the cam. I now have 150 with the new cam.
add oil goes up too 180 again. Now i never tested compression after i changed cam till i had the smoke problem. Never took the head off it was running great. The fan was turning on and off, so never showed it over heated. What are some recommendations because i cant keep sinking money in it. But i do like the machine. I have not read any problems relating to this anywhere i have seen countless cam changes and never heard of a head gasket blowing.
To throw the idea out there could i have my carb set wrong getting the smoke there is no water in the oil nor can i see it in the cylinder when i take the plug out. And it is VERY hard to start since the smoking - at first once i had gas fired right up and idled now takes 5-10 min

 

First off you shouldn't be able to get compression readings like that if the cam detent is working properly. 65 to 90 psi on average is what the a manual says on compression. Most I've gotten on a good running machine is 100 psi.Smoking could be piston/ring related,valve guide seal leakage,etc. Normal carb pilot screw adjustment is 2 1/2 turns. If you don't have a service manual here's a pdf link to a cheap 5 buck manual that will help you on repairs and service.This 2002 manual is basically the same as you model.2002 Polaris Scrambler 500 Service Manual PDF Download

 

Thanks for the response, but why would it run "better" before i changed the cam.
And the cam is bad for sure it was almost round on the exhaust lobe. But prior to this i had no smoke, started up good ect.
But i will look into it for sure
and how would i check the cam detent

 

On the end of the cam is the detent lever and spring.You should be able to flip the lever and the spring should make it return.Smoking is something probably other than cam related. In the manual link I gave you there are several things to check. It can help better than me on eliminating problems. Here's one pic from the manual on cam timing for instance.