Please forgive the length of this as I want to provide as much detail as possible.

I bought a non-running 2001 sportsman 90 that was just low on compression (supposedly).

I ordered the top end kit (piston, rings, cylinder ect) as I have for several other little bikes. During the teardown I noticed the fan/flywheel had strange play in it. Turns out the rivots holding the flywheel together were loose letting the inner and outer flywheel rotate about 5-10 degrees. I bought a used flywheel and stator off Ebay (from a 2002 model) and installed with the new top end kit.

The bike starts and idles perfectly on the first kick. When it is stone cold it will run with power for about 50' then bogs out and stalls at anything other than idle. It just dies out at any push of the throttle.

I did a lot of searches and here is what I have tried so far.

- Cleaned the carb (multiple times) all jets are clean and the bowl fills as it should.
-inspected the reeds. all 4 are there and seem springy
- Cleaned the stator with electrical contact cleaner spray.
- sanded the stator outer flats with emery cloth
- tried the cone filter that came with the kit , no change
- tried the factory air filter, no change
- tried the cone filter with shop rag wrapped around it, no change
- unhooked the throttle switch , It did not run much with it disconnected so I feel it is ok.
-unhooked the electric choke , No change with this either way.
- made sure the spark plug gap is correct
- unhooked the exhaust from the head - loud but still no change.

I have not ohm the stator or run a compression test, but I suspect both are ok. I will check both tonight just to be sure. I have read the electric chokes are crappy on these bikes. Is there any way to trouble shoot this? The carb does seem to fit tighly into the intake so I think that is ok.

It has a battery in it but not sure of condition as the electric start does not work with the switch. I can make the starter work with my jump box. I suspect the relay. Not sure this has anything to do with it but trying to tell all I know.

I am fully open to advise here as I am trying to avoid just throwing parts at it.

Thank you
Tim

 

What is the factory setting for the clip on the main needle for the carb? I have not looked at that yet.

 

Compression by the manual should have at least 115 psi. Stator Black wire to White/Red should be around 450 ohms.Black wire to Black/Red should read around 850 ohms.This last connection seems to be the one I've had the most problems with on the little ones.Could be that the used stator is weak. Yes the relay can be a fault,but check out the starter lock out switch in the brake lever that triggers the relay. If the relay just clicks,then possibly the relay is bad,if it doesn't then possible the little plastic plunger in the switch is bad. And yes electric chokes don't work! Easier just to block off the air intake with your thumb to crank one when cold or refit with a manual choke kit(if you can still find them) or even aftermarket carbs on ebay have the manual choke models.
http://www.ebay.com/itm/Carburetor-Polaris-Sportsman-90-90cc-Manual-Choke-Carb-2001-2006-/181544610735?hash=item2a44e6ebaf&vxp=mtr Try the needle clip on the middle(3rd notch) and see what it does. From there you can try leaning or richen up the needle posititon.

 

Thank you. I will try the Ohm readings tonight and see what happens. Will also test compression. I'm trying not to get crazy buying parts yet, but everytime I start it after trying something, my 7&9 year olds run and grab their helmets hoping it is fixed. Also if I buy that carb, do I just not hook anything to the choke and use the thumb cover trick to start it?

 

Oem cable and choke lever would still have to bought to use it from places like Cycle Parts Ware House.Item 13 on the choke lever. Dirt Cheap Yamaha, Polaris, Suzuki & Kawasaki OEM Parts & Accessories – Cycle Parts Warehouse but the choke nozzle,spring and plunger come with the carb. You could still just block off the air intake with your thumb to start. I've even had to do that on some manual choke models,because the engine vacuum is so low to start pulling fuel without a little help. Once the 4 strokes came out,choke starting wasn't a problem.

 

Okay the black and red wire puts out 764 ohms the white and red wire puts out 108.

That means I need a stator correct? Where do you recommend I buy one?

 

At +/- 20% allowed, the black and red(main stator) is pushing minimum,the red/white at 108 is way weak. This is the trigger coil. Sounds like you need a new stator. You can take a chance on the 25 buck one from ebay like a lot of people have done.http://www.ebay.com/itm/Stator-FITS-POLARIS-ATV-SPORTSMAN-90-2001-2002-2003-2004-2005-2006-Magneto-/290792502604?hash=item43b495754c&vxp=mtr or Ricky Stator has a good reputation,but higher at $125. Ricky Stator - Products

 

I really appreciate your help. Thank you.

 

USPS apparantly lost my stator. It says it was delivered Saturday at 11:58 AM. I checked 15 minutes later and it was not there. Had to order a second one and file a claim with the post office as this does not appear to be the sellers fault.

To be contunued......

 

My stator showed up today. That didn't fix it. I just ordered a new manual choke carb. Fingers crossed.