I recently bought a Polaris xplorer 500 AWD from my friends dad. It needed a little tlc so I got it for a good price. Did a carb clean, new plug, new prop shaft u joints, ect. It's main issue was that it wasn't turning over. I know I had power going to the stRter because I used jump cables and hooked them directly to the starter and the starter would struggle to turn over the engine. Maybe one compression stroke every ten seconds. I replaced the starter and starter clutch. Still having the same issues. My next guess Is the auto-decompression inside the cam shaft. I wanted to see if there was something I was missing before I replaced the cam shaft

 

Yes the cam is the logical place to look. If the exhaust lobe wears down some would run at an idle and pop back if you give it throttle. If the compression release device is messed up that can cause problems also. Remove the thermostat housing to get to the cam cover plate. ith pressure off the ball bearing on the exhaust lobe the lever should be able to flip over and spring back. Make sure the spring hasn't slipped or broken.http://forums.atvconnection.com/pola...d-cam-pic.html

 

I was also wondering that if my timing was slightly off if that would give me issues. I checked my timing by taking the bolt off of the flywheel cover and turning it over with the pull start so the timing marks were showing. I then took off the cam shaft cover and there was a line on the cam shaft gear that was parallel ( vertical ) to the cylinder and piston. I assume this means that my timing is correct

 

Should look like this at tdc.

 

Looked inside the decompression cover next to the thermostat housing today and the lever moves and springs back but is very very weak. It takes very little force to move the pin back and when I release it, the pin springs back. Is there suppose to be more tension on the pin or is it suppose to be that loose?

 

Spring won't have a great deal of force on it. Centrifugal force from the engine spinning over holds the decompression device open and when the engine starts,the spring helps bring it back to the stop pin and keeps it there.

 

Should I still replace the cam shaft since the auto decompression seems functional or should I look somewhere else?

 

Turn the cam to where the bearing hole is exposed and see if the bearing pushes up correctly when you hold the detent lever open. If there is any wear or damage on the bearing holder or the rocker arm it might be time to replace the cam along with the rocker arm. Before you do just check out other items such as having a new battery first,check that the the starter and bendix are in good working order and cables are tight. Simple things like this may be the main problem,not the cam.

 

Ok so here's my story:

3 months ago, I had replaced Cam and Rocker Arms due to bogging throttle at half to full throttle. . New cam and rocker arms fixed that bogging issue. Please note that I didn't keep the cam and the rocker arm DID have groove where compression release ball wore it down. Please don't judge me but this was right at the beginning of Texas deer season. I didn't have time to continue troubleshooting.

Upon putting the new cam and rocker arms in and setting valves clearance, throttle was fixed BUT immediately new issue was that when you try to rope start it OR use the starter AND the next stroke was the compression stroke, it is HAAARD to get past that stroke.. BUT once past that initial compression stroke, rope start or starter was EASY PEASY!!!!...

I DO believe that little spring is installed correctly for that detent shaft but I'm going to tear everything down again and regain access to the valves and detent and spring and cam and reverify the spring installation just for grins.

My first initial through is that something is slightly off with timing where that compression ball isn't hitting the rocker at the right time to release that pressure .. I THINK.. that is just my initial thought.. I know Old Polaris Tech helped me the past with few other issues with some other 4 wheelers but this one is mine and I'm trying to get this fixed now. SO, I have saved the image that Old Polaris Tech posted about the timing alignment, that will be VERY HELPFUL to check but right now my main question is about the compression release ball on the cam. IF everything is supposedly in line with timing, shouldn't that compression release ball hit the rocker the right time to release pressure to allow for easy start?

I don't see any reference to where that compression ball is in relation to the alignment of the timing. That is were my disconnect is at the moment.

Again, thanks in advance for any and all information and guidance..

 

I forgot to add that I replaced the starter (with DB electric) as it finally died (OEM) probably from the compression it would try to push past. Also that I ensured all connections are good and tight. Battery is not new but still holds 100% of the charge so that shouldn't be an issue...