2002 sportsman 700

[Tom Walters]

Working on 2002 700 sportsman in shop. Engine has no power. Pops and backfires at 1/2 throttle and above. Carb is clean. Good fuel flow. Checked stator output with DVA. 19v on charge coil. 6v on pulser. Would like to know if this is cdi related.

[Frank Angerano]

Handlebars. The throttle have wires going into it? If so open it up and you will find the rev limiter.  Try to separate the wires and see  if that clears things up.  Sometimes on the polaris bikes the rev limiter starts acting up.  

 

 

[Tom Walters]

don't think rev limiter is in handlebars. That would be throttle safety switch. I umpluged black wire to handlebars eliminating all switches up there

[Frank Angerano]

Double check that its not a separate set of wires in the handle bar. As well as trace them to be sure they are disconnected.  Or do what I did. Reconnect  everything and then open the top cover on the throttle and run the bike. While is backfiring etc separate the contacts on the throttle control and see if it clears. Only reason I’m pushing this theory is it happened to my bike and solved the problem.

 

[Tom Walters]

Switch is not problem. What do you know about cdi box with built in coils?

[Frank Angerano]

Could be the cdi but not my first choice.  I would do some testing first. Maybe test some devices like the  pick up coil for starters. Also the stator coil maybe do an ohms test as well look at the secondary ignition coil.  Sometimes the spark breaks down after the engine is hot or in your case maybe it’s happening right away.  There is a tool to see if  the spark is breaking down while the bikes running. 

Its a useful tool. 

 

I know we are talking about electrical items are you sure it’s not a foiled plug or a fuel rich condition happening ? Or timing ? 

Lisle 20610 Inline Spark Tester https://www.amazon.com/dp/B0002STSC6/ref=cm_sw_r_cp_api_i_ebj1CbF42SW39

[Tom Walters]

Have that spark tester. New plugs, old ones looked ok. Made no difference. Gave you cranking voltages of charge and pickup coils in first post. Went thru carb with fine tooth comb. Polaris updated that ign system in 2004 or 05. Timing is on speck. Had flywheel off to check for damage, (loose magnets, Burnt coils) looks good. At a loss

[Frank Angerano]

I read that you gave  the cranking voltages on the first post.

NOT cranking voltages.Ohms reading on the coils like a said in my last post. This will at least put the coils in spec.  This should also be done on the rectifier/regulator. 

I remember a similar topic on this and it turned out to be a pick up coil that was the problem. Is was a hair to far from the flywheel and on higher rpms is started to act up causing this problem. It was in the Polaris forum. I would not be surprised if it’s the same thing.    

It was a while ago but should still be in the topics section of that forum.  

Maybe @Ajmboy or @Admin can help us dig it up?

I believe it was the gap between the pick up coil and flywheel. There is a spec limit on that.  

[JacobSlabach]

sounds to me like a badly adjusted carb.  does it get better or worse as the motor gets warmer?

[Tom Walters]

no change as motor warms up. What would I look for if cam or lifters were bad. Going to try different carb but think I am spinning my wheels.  

[Frank Angerano]

Did you check the gap on the pick up coil ?

Your going to feel like your spinning your wheels and it gets frustrating. Keep calm and it will get sorted out. Some problems are more in-depth then others.  Process of elimination.  

[Tom Walters]

Sometimes get puff of smoke out of carb when clicking starter. Some times eng kicks back when trying to start. timing is about 9 degrees at idle. Book says 8

[Tom Walters]

coil gap is in spec.

[Frank Angerano]

Have you checked timing ? 

[Tom Walters]

yes. previous post.

[Frank Angerano]

You may have to take a look at your valves and rocker arms etc. It’s possible somethings going on in there.  The back fire and puff of smoke out of the carb all though sounds like a timing thing but I guess it can’t hurt to have a look at the top end to make sure it’s all proper and valves are opening and closing the right way. 

[Locke DoBay]

I had the exact same problem with mine. I replace the cdi and changed it over from DC to ac using a conversion kit I got from a shop in Canada but still had the same problem. A friend came over one day and we got to talking about it and he was like can I take a look, sure why not. He took the carb out and drilled out the brass plug for a needed that was underneath of it. Made an adjustment to it and put back in. It ran like it was new. No problems since, 70 mph, and felt like it even had a little more get up and go from a dead stop. Hope this helps, I could have saved a lot of money and time if he would have stopped over for a beer sooner lol.

[Frank Angerano]

Most people don’t know that the screw even exists. And then try to tell someone to drill out the carburetor??? Lol we have had this discussion before and there’s so many more times this will probably come up again.  It’s like finding a hidden door! 

[Locke DoBay]

I never knew about it. And sure will never forget about it now. He said it had something to do with CA laws. I guess just in case it ever found its way out there but I don't know for sure. 

[Frank Angerano]

I’m sure it has to do with some dumb law but hey at least they make it so you can drill it out.  Good luck brother and ride safe.