HELP, We're stumped

[bdolinski]

When in doubt go for a new set of eyes. The bad news. (I'm going to try to keep it short) Out riding and let my 2003 700 SKS buck, brought it up to a good clip but it didn't want to take right off, she hung around 70. It seemed like it was a clutch issue so I let off and then stabbed the throttle again and it took off. Played for a short bit, dove off into the snow to cool her down and then came back out on the trail. Stabbed it again but couldn't come close to the speed I was just at. I was forced to finish the trip to get it back out to the road, by the time I got there it wouldn't go more than 28 MPH and it wasn't missing as much as it was limiting. Here's what we've tried.

Carbs, clean nothing missing
Changed plugs, cardboard brown in color, same issue with new plugs.
Black wire unplugged to remove all the switches from the troubleshoot, same issues.
Brand new temp sensor, same issue
ECU from two different sleds, same issue
CDI (coil and wires) from a running sled, same issue.
Service manual, Checked the ohms per the service manual for the coil, stator, and all electrical.... Nothing tested bad.
Tested the Throttle position sensor, tested good with the polaris 9v tester.
Exhaust valves removed, looked good on both.
Timing check, 10 degrees roughly at idol, bouncing all over at wot as the sled seems to be limiting all the time when you give her.
Took out the bore snake camera, top of piston and cylinders look good, skirts look good, rings and all that look good. Pulled carbs again, reeds look good, scoped lower end and everything looks good.
Both primary and secondary clutches just came back from SLP this year and have been great, the mechanic helping me thinks hands down electrical.

My friend is a Polaris mechanic helping me. He's going to call tech this morning to see if they have anything to help. I'm going to the Forum for a fresh set of eyes.

Thanks for any help in advance.

 

[MARV1]

Exhaust outlet on can, check for dents/ restricted outlet... Baffles loose in can?

 

[Jay]

You should have more than 10 degrees @ idle, and if the timing is all over at higher rpm I'd pull the flywheel and see if the key is intact or if somehow the flywheel is slipping.

 

[Goinboardin]

Timing should be ~29* BTDC at 3250RPM with the TPS unplugged.
But if the controller is seeing DET or getting a bad temp reading it will pull timing.

You sure that new temp sensor was good? When things get weird like this you have to assume nothing, and measure everything.

 

[sno*jet]

When in doubt go for a new set of eyes. The bad news. (I'm going to try to keep it short) Out riding and let my 2003 700 SKS buck, brought it up to a good clip but it didn't want to take right off, she hung around 70. It seemed like it was a clutch issue so I let off and then stabbed the throttle again and it took off.

gets up to 70, then goes faster after you blip the throttle? maybe the secondary is a little bound up. is it aligned properly?

 

[bdolinski]

Another 2 hours spent yesterday.... This thing is a real pain in the.... wallet! I did pull the flywheel again, the key is intact. We tried a second temp sensor from another working sled, this is the 3rd sensor we've tried now. I'm going after the timing today. We rechecked fuel and even made sure the crank wasn't bent by indexing the cylinders.... I believe I'm going to take off early from work to head to the shop, crazy how these things can consume someone! I believe I have access to both a primary and secondary clutch that I'm going to put on to rule out the clutches.

 

[550iq]

With the other stuff looking ok, my thoughts were dirty, wore out clutches.
An ill mannered drive system can make all kinds grief. Looks like you are narrowing it down. Happy trouble shooting. 550iq

 

[winter4ever]

My brother had an 06 600 that always ran good, then one day it just started to run like garbage. We basically did everything you just mentioned, fought it for a year. it ended up being a twisted crank, Im not sure how you check for it, but your polaris mechanic should be able to check i guess?

 

[Jay]

Mainshaft or jackshaft bearings? You didn't suck a rock or something up in the track? Melted sliders?

 

[bdolinski]

I dropped in a new stator and we're back at square one! The stator didn't fix it either. I need to find another sled to swap parts with to trouble shoot this issue I believe. Frustrating for sure. We used a dial indicator and degree wheel to make sure the crank wasn't twisted. We checked the piston was at the tdc or bottom (can't remember right now) lined up with 0 on the flywheel marking. rotated the crank around until we were at the same piston location on the 2nd piston and checked the degrees off, 120 I do believe. UFFFF-DA! even went after random stuff, unplugged the dash wires, head light switch, hand and thumb warmers, different key switch, and the list goes on.

 

[old fat guy]

180 is half a rev

 

[Jay]

What old fat guy said, if you've got 120 degrees between tdc on two cylinders you just found your problem.

 

[Betterview]

What old fat guy said, if you've got 120 degrees between tdc on two cylinders you just found your problem.

I believe if this is a three cylinder that should leave the proper spacing at 120 if they are evenly spaced. If it is a twin then you have found some thing.

 

[Cardiac Kid]

Check the det senser also I have had these go bad.

 

[Cardiac Kid]

Oh and Check the springs in both clutches just because they just got done my SLP doesn't mean you didn't get a Bad spring that broke. Very common problem and will cause all kind of issues with the running of a sled.

 

[bdolinski]

Thanks, it's fixed

It's alive! We had blown air through the exhaust and tried running the sled without it on there with the same symptoms. Long story short is it was the exhaust can. Not the pipe, just the can. I put the stock one on there and I'm back up and running. I sure learned a LOT through all of this. Thanks guys!

 

[Goinboardin]

Marv was dead on then! Thanks for reporting back what the issue is. Its pretty common for someone to get a good thread going like this, solve the problem, then never report back.

 

[X2Freeride]

If it was a SLP can honestly this is fairly common.

 

[moly may]

You talk about team work and helping the fellow rider! Very impressive guys. The very reason i get on this forum. What a MASS of knowledge.Agreed, thanks for the final report!