2001 Sportsman 500HO question

[elf]

Got a question for any ATV mechanics out there. My sportsman 500 has starting issues. You hit the starter and sometimes it'll just barely move/engage /won't crank or turnover. You can do that repeatedly (3-5 times) and then all of a sudden it starts to crank and starts fine. I've replaced battery and starter and its the same. I've also noticed if I try to pull start it sometimes it about rips the handle out of my hand. So it seems like the compression is too high, maybe a valve not opening sometimes. Is there a decompression valve on these to allow them to turn over easier at start?
Once it cranks it'll always start and run fine. Not a huge deal but it's annoying.

Thanks for any ideas!

 

[srt20]

Needle and seat leaking? Filling the cylinder with fuel and making it hard to spin piston over?

 

[jonesin]

I am going to watch this thread, I have/had the EXACT same thing on my sportsman 500 but I replaced the battery a month ago and it starts everytime, for now....
I certainly know what you are talking about ripping your arm off! I was scared every time I had to do it!

 

[elf]

So I've done some more research on this and there is a decompression lever located under the valve cover. I haven't gone to the extent of tearing into it yet and don't know that I will but they are saying you can replace the spring on it. The other info I've learned is basically saying that sometimes when you shut them off the piston/crank are in the perfect spot (bad) to make this happen. If you notice it when you hit the electric start you should pull the recoil rope a bit until it turns easy (past the hard spot) and then hit the starter. Last night it started fine so I'll find out the next time I need to plow snow. As far as ripping the recoil rope out of your hand in the info I found online one guy had his wrist broken when it happened.

 

[jonesin]

As far as ripping the recoil rope out of your hand in the info I found online one guy had his wrist broken when it happened.[/QUOTE]

I
started to chuckle but it really isnt funny, I have literally had my wrist and arm hurt the next day too, it happens so fast...
I fought with a weak battery for a while because it would almost always start unless cold...

 

[jonesin]

did you ever do anything about this?
I think my crank went bad loosing the exhaust lobe, I am tearing it apart and wondered about the decompression valve you talked about...

 

[jonesin]

never mind, looked it up and it comes on the new cam
did you replace cam? wondering how hard it is? looks simple once you get plastic and stuff off

 

[elf]

I haven't done anything to repair the issue. Starts OK most of the time, if it won't turn over I just pull the rope about 1/2 way and hit the starter again and it seems to be fine. Sometimes I just keep hitting the starter for 1/2 second or so and after doing that a few times it'll fire.

Keep us updated on your repair, I'd be interested to know how complicated it is and if it solves the issue.

 

[jonesin]

I will do that
I took of the plastic and tank, pulled the valve cover and took the rockers off, the cam is DEFINATELY shot!
I ordered new cam, rockers, valves, springs, gaskets, thermostat all for $260, should be here sat or monday
I am looking for someone to grind the seats to match valves before putting it together, I might see if they will just put the whole head together and set clearence so I just bolt it on....
It was really easy to get to this point, hope it works...
I have 6100 miles on it with 4 years of broken speedo in there so it was prob time...

 

[jonesin]

elf,
you can get to the spring by pulling the 2 bolts on the water intake and then the 3 little bolts on the cover behind water line which is the cam cover
you will see the decompression valve and spring right there
the whole valve assembly comes out on a rod, the engine has to be at the right spot so it will slide out, I will have to double check which way the valve points when I get it back. (it wont slide back in unless this little ball bearing on the cam is rotated to the bottom so it drops out of the way.
you can see valve and spring on the attached cam pictures
the spring is really light weight and thin, it kinda spins and rotates
if yours is broke you can have my old one, its still intact

 

[elf]

I appreciate the offer! Sometime this summer maybe I'll try to tear it apart and look. Been starting OK lately.