Since you guys are so awesome with 2-strokes, I figured this was a pretty universal situation and hoping you can help. Wife's 2000 Polaris XC SP 600cc with power valves (VES).
It's going down to one cylinder after it warms up. First I cleaned the carbs as I did with my SRX. That didn't help. Once warmed up and left idled, it'll run very weak and the temp light will be on. If you gun it down the road after about 50 yards it'll kick the other cylinder back on and the temp light goes off, but still doesn't seem quite as powerful. I cleaned the exhaust valves and found one diaphram torn, so replaced that, no change. We rode it on Sunday and even though it was acting up, the plugs looked great after that run but the problem was becoming more frequent. I'm pretty sure the compression was 125 on each hole before and 120 after the ride, but due to variables I didn't get too excited about that since they were the same on both holes. Put in new plugs after a more thorough VES cleaning, and pulled them to check them out after a test run. Now they have a dry white substance on the electrode. I suspect a leaking base gasket. I pulled the head and it's got o-rings, they look okay. I took the jugs off and the base gasket tore apart so I can't tell if there was a problem.
Do you think I'm going down the right path?
I also noticed that the residue on the top of the pistons is sticky, and I noticed a faint antifreeze smell when I pulled the mag side exhaust valve off the first time, but I wasn't sure if that was from standing near the hoses and overflow tank. Also, it's using some antifreeze, as I've had to top off the reservoir after each run, and I don't have a leak on the floor of the shop. I guess I figured it could be due to all the hoses and whatnot maybe there was a bubble in the system that got burped out. Or it's burning it.
All roads point to a leaking gasket, and I figured once it's warmed up and the thermostat opens, coolant starts running through the engine and contributing to this. It acts like a fouled plug.
Any thoughts? Thanks in advance!
It's going down to one cylinder after it warms up. First I cleaned the carbs as I did with my SRX. That didn't help. Once warmed up and left idled, it'll run very weak and the temp light will be on. If you gun it down the road after about 50 yards it'll kick the other cylinder back on and the temp light goes off, but still doesn't seem quite as powerful. I cleaned the exhaust valves and found one diaphram torn, so replaced that, no change. We rode it on Sunday and even though it was acting up, the plugs looked great after that run but the problem was becoming more frequent. I'm pretty sure the compression was 125 on each hole before and 120 after the ride, but due to variables I didn't get too excited about that since they were the same on both holes. Put in new plugs after a more thorough VES cleaning, and pulled them to check them out after a test run. Now they have a dry white substance on the electrode. I suspect a leaking base gasket. I pulled the head and it's got o-rings, they look okay. I took the jugs off and the base gasket tore apart so I can't tell if there was a problem.
Do you think I'm going down the right path?
I also noticed that the residue on the top of the pistons is sticky, and I noticed a faint antifreeze smell when I pulled the mag side exhaust valve off the first time, but I wasn't sure if that was from standing near the hoses and overflow tank. Also, it's using some antifreeze, as I've had to top off the reservoir after each run, and I don't have a leak on the floor of the shop. I guess I figured it could be due to all the hoses and whatnot maybe there was a bubble in the system that got burped out. Or it's burning it.
All roads point to a leaking gasket, and I figured once it's warmed up and the thermostat opens, coolant starts running through the engine and contributing to this. It acts like a fouled plug.
Any thoughts? Thanks in advance!
Last edited:
I guess what I'm getting at is could it be something else entirely, like a weak ignition, CDI box, plug cap? What else would be affected only when it's warmed up? Choke is not sticking.
I'm just a little concerned that there wasn't an obvious leak, so I don't want to be chasing my tail all winter now that we have snow!! I'm decent with mechanical/carbs, etc....but not real experienced with electrical issues.
I'm just a little concerned that there wasn't an obvious leak, so I don't want to be chasing my tail all winter now that we have snow!! I'm decent with mechanical/carbs, etc....but not real experienced with electrical issues.
Did you clean the carbs on it this year? When the sled is warm the 1 cylinder dies?? Flip the choke on it to see if it comes alive again. If it does, your pilots probabaly plugged. I have never heard of a yammi cylinder cuttting out even from a valve or cable problem
Yep, cleaned carbs, pilots are clean, along with main and air screws, did not touch floats or needle. Choke kills it, tried that.
Dont ya just hate mysteries?
Did you try and swap the coils around to see if the other cylinder will quit when it warms up? Good luck with this one. All we can preety much do from here is trail and error.
Did you try and swap the coils around to see if the other cylinder will quit when it warms up? Good luck with this one. All we can preety much do from here is trail and error.
horkn
New member
tomseal6 said:
I have this exact same sled. it is my daily riding sled, and I have owned it since new, spring ordered it even...
no power valve gummyness or full on stuck power valve will cause this.
All stuck or gummed up PV's will do is make it doggy down low, but not operate on only 1 cylinder.
to me it sounds like you either have a bad coil, or possibly a leak in your head/ base gasket. You did mention weird deposits on the one plug. Did you say the coolant was getting low?
Bottom line, something is wrong,a nd you will need to figure it out soon, or get stranded.
fwiw, this sled is a little fussy about having enough snow so that the temp light does not come on. On icy trails, with little or no snow to lube/ cool, the temp light will come on. But in 99.9% of cases, a quick jaunt off trail will get it back to normal temps.
edit....
I re read your post, and to me it sounds 100% to be the base gasket. Your logic to me sounds right on.
should be a simple fix... also, mine has been completely pull and go since new.
Last edited:
Thanks for the info guys, I've got it apart so I'll be putting new gaskets on top/bottom and we'll see where I'm at after that.
Horkn, you mentioned the temp light coming on, is that due to no snow hitting the cooling fins underneath?
Do you know if the temp light is only for the temp, or if it's a 'generic' idiot light that will trigger with a misfire, like the 'engine' light would on a car?
Horkn, you mentioned the temp light coming on, is that due to no snow hitting the cooling fins underneath?
Do you know if the temp light is only for the temp, or if it's a 'generic' idiot light that will trigger with a misfire, like the 'engine' light would on a car?
it sounds like the temp sensor is gone if its the same system like their 7 and 8 s its in the center of the head 30 bucks
could be the det control is un plugged same kind of symptoms
good luck
could be the det control is un plugged same kind of symptoms
good luck
terret725
New member
try a cap then a new coil. just had a 500 ves at work with the same problem a new coil clean it up. then if start chasing wires checking for chafing or broke wires. big spot to check is right at the plug that goes into the wiring harness from the motor. theres a few wires that kinda jump one plug to the other and they break and cause all kind of problems. also check ur needles on ur carbs. they some times, very rearly but some times, the little clip that holds them in the slide comes off. not the little liek c clip but its like a little J that is part of the slide that holds it down. when it comes off the get get bent. but most likely it sounds like the coil. not sure but i dont think they had the DET in 2000. thats the old domestic motor. the temp sensor shouldn't cause the problem as far as i know. havent heard of it or seen it since ive been working at the shop. i could be wrong tho.
terret725
New member
oh and if ur leaking coolent into the motor ur also leaking air into the cooling system. pretty much pressurinsing it and making it so the coolent cant flow. so the light coming on is prolly it realy over heating. try touching the motor while its running and if it gets hot where u cant hold ur hand on it then its too hot and ur over heating.
horkn
New member
MnHiFlyr said:
the temp light on this sled is nothing more than a temperature on/ off switch per say. if the temp hit a certain number, it turns on. When the light does come on, the timing defaults to a lower setting, and power output is reduced.
there is no detonation control on this year sled. that was added later. So it will not operate light a check engine light on a car.
yes, when I ride on super hard packed trails or a bare ice lake that have no real snow that can kick up onto either the floorboard mounted exchangers or the front tunnel exchanger(there is no rear exchanger), I will get the temp light to flicker on until I venture off trail, or find some snow on the trail. It quickly resumes to non temp light on, full power mode. I think the light and lower power output is engaged early as a safety precaution. but if there is any snow to be kicked up, the light should never come on
does the light come on in both premium fuel setting and in reg gas setting? most times I run mine in reg setting, as the thing makes so much power for a little 600. I do also recall when it was new, I would run premium gas msot of the time, and run it in the premium, or "hot" ignition curve since it is wortha few ponies, this was the last time that I had really encountered any temp light flickerage. I suspect you have as was mentioned before, coolant leaking into your motor, and maybe that is allowing air bubbles to block coolant from passing.
once you fix the gasket issue, make sure and bleed the coolant well so there are no air pockets which will restrict the flow of the coolant.
keep us posted.
journeyman
Active member
Have you talked to a Polaris mecahnic yet? The reason I ask is the same issue happened to one of our guys on one of our UP Michigan trips about 5 years ago. It was a 2001 model. He took it to the dealer in Bergland twice with no luck. Then we hauled it down to Ironwood and they fixed it. I am pretty sure they changed the thermostat, the temp sensor and bled and purged the system. The mechanic told him he had seen alot of cooling issues with that model of sled. The next year it happened again and he sold it and bought a new 4 stroke Yamaha. He is the one that now owns the ATTAK we ride with and is the avatar photo I use on the 4 stroke forum.
horkn
New member
notice he has coolant loss issues. that means a gasket or hose or something is bad. Since he is not seeing any puddles, it almsot has to be getting burnt in the motor.
Check/change the temp sensor. It is designed to retard the timing if the sensor senses and overheat and it will barely run. Cheap part and right on top of the cylinder heads. Easy fix, hope that's it!
Thanks for the tips guys, the sled is sold. Sticking with Yamaha from now on.
horkn
New member
gaskets can go on Yamis as well.....
Polaris makes a nice sled, always have, always will. That said, my next sled will probably be a yami 4 stroke.....
Polaris makes a nice sled, always have, always will. That said, my next sled will probably be a yami 4 stroke.....