WE HAVE AN FST THAT WILL NOT START AT ALL. IT HAS BEEN HOOKED UP TO THE COMPUTER AND IT TELLS US THERE ARE NO CODES AT FAULT. HAVE SWAPPED MANY PARTS AND STILL WE HAVE NOTHING. THERE IS GOOD SPARK AND THE PROPER AMOUNT OF FUEL AT THIS POINT. ANYONE HAVE SOME IDEAS. THANKS :frech32:

Did you get the starter fix done?

I think that I would try and put a little fuel in a least on cylinder to see if it would fire maybe you have rail pressure but no fuel going into the pistons good luck


let,er Buck :banghead:

If you have compression, fuel, and spark only thing left is timing. Otherwise it will run.

Are you doing this, or is the dealer?

If you ARE doing this, why are you not taking it back to the dealer?

Did you swap out the computer? Change the plugs (almost brand new plugs went bad on my RX-1 several times when it was new) so be sure you are swapping them out.

Finally, these sleds need full 12 volts to run. If you are running on low battery...jump the battery and see if that will improve things. No battery power will definitely cause no start.

CHeck your 20 amp EFI Fuse located on the air filter assembly :doh:

This is at the dealers shop. All bulletins have been completed at this time and there is plenty of fuel getting to pistons. Once again the diagnostic computer tells us there is nothing wrong with this sled.

Seriously, then....change out those iridium plugs. They foul easily, and look normal. Put jump on battery while your at it.

The OE plugs aren't Iridium, they are a Platinum on the turbo and copper core for the natural aspirated engine.

Whatever, they have pencil lead thin cores and I had lots of issues with them with less than 50 miles on my RX-1 (couple of those, as a matter of fact) and changin out the plugs fixed the problem, and the dealer came right to that answer over the phone as soon as I described the problem.

Change'm out.

I agree with smokelessone. These buggys are tempermental when it comes to these types of sparkplugs. If its got fuel, and spark no reason not to run, except for fouled plugs!

$17 bucks each :banghead:

Prolly why the dealer has NOT tried to change them, along with the 'ease' of changin them out. :-)

I had to change the plugs on mine, before it left the shop. I put in stock Champion RC7PYCB Platinum Power spark plugs.

I have had no starting problems since then.

To properly deal with an overrich cold start condition, it is important that
Every time the engine is started it should be run until it is close to operating temperature (140 to 150F) before shutting it off.

Otherwise, the spark plugs may get fouled, and need to be changed. I know this from first hand experience.

Thanks Excursion-

That will save everyone some $$$.

The plugs have been changed various times, the fuel pressure checked, spark checked. Hooked to the diagnosis computer many times, and stil no start. We did however get a violent backfire which is leading us to believe the flywheel key may have sheared. We will keep you posted.

Backfire on startup usually means a timing issue, but it could also be a computer issue with these high tech sleds. I would swap out the computer first before digging into the bowels of this sled.

Backfiring on these machines at startup is actuall common, thats why the one piece starter gears failed. The FST is running something like 16 degrees of timing at startup, which is computer controlled. I would use the digital wrench on a known good running sled in the same ambient air temp and print out all of the sensor readings. Then do the same for yours, more than likely something will be vastly different.

I have started both my FST's dozens of times and not one backfire. Would not want that happening to my sled, whether it be two stroke or four.

I was told that the backfireing and bad cold engine starting is from the computer dumping fuel after start which it is supposed to do. Polaris is coming out with a reflash to limit the amount of fuel after start.

Sounds like the cam timing has slipped

We have torn it down and found that the flywheel key which is not a key at all but simply a small pin no bigger than a match head had been sheared off. waiting for parts now. we'll keep you informed.

Well, either the flywheel was not adequately torqued or the interference angle between the flywheel and shaft is not great enough. All the pin does is index the flywheel. If properly torqued you can actually take the retaining nut off and flywheel will not slip while running. Been thru this problem with diesels. If not locked on the angles properly and the engine back-fired prior to "no start" this would also improve chances of flywheel rotating and breaking pin. Pins and keys are not designed to be the retainer.

It appears that while being assembled no loctite was put on the flywheel prior to installation. What can a little glue do for you?

kill button

Wouldn't locktight be counter productive when you want to pull the flywheel? Never seen any application where locktight was used on a flywheel. Keyway assures proper light up, and also serves as a shear pin if you get an abrupt stop. Proper torque on the flywheel bolt should keep the whole deal inplace without the need for locktight. But hey, new applications come along everyday too, so what do I know??

I remember a dodge tailight that was only glued into the rear fender once and could not believe that some quick attach mechanism with a stud or bolt was not employed...and my friend who bought that car never has lived that one down either, when it fell out and dangled by the wiring.....

The flywheel SHOULD NOT be loctited to the crankshaft! The interference angle, usually 1/2 to 1*, difference in the angles on a tapered crank locks the 2 together just as on the drive clutch.

Untrue! The service manual states that four small beads of loctite need to be applied to the crankshaft prior to assembly. The pin is only for assembly and is not a key.

I wonder how many of us didnt get the loctite with the starter gear update.

Well then Polaris screwed up and there will be more of the same type failures, if this is a tapered shaft and they are counting on Loctite to hold the flywheel in place.

You don't have to remove the flywheel to take the starter gear out.

None of you got loctite on the flywheel during the starter gear update.

The flywheel was not removed.

Try to be positive!

DID THIS SLED HAVE THE STARTER UPDATE DONE ,AND THEN WOULD NOT START? IF IT DID , IT MOST CERTAINLY HAS A PINCHED WIRE UNDER THE MOTOR[ WILL BE A WHITE WIRE], THAT IS PINCHED, THIS HAPPENS WHEN THE MOTOR IS EITHER JACKED ON ONE SIDE OR PINCHED PUTTING MOTOR BACK INTO SLED. I TALKED TO ANOTHER DEALER TODAY THAT HAD THIS HAPPEN. GOOD LUCK

Makes me wonder if the troubles are coming from dealers doing the updates?? I did 3 of these updates today, for 12 in total, and have never had to jack or remove an engine. There is plenty of room to remove the engine side cover without putting strain on mounts or causing wiring issues. Like EPSD said, theres no reason to remove the flywheel.

I bought 4 from here
~2$ a piece

WWW.championsparkplugs.com

Ta da!!!! All is said and done, the flywheel was reinstalled with the loctite and torqued to specs. It fired right up, let's go ride.

Nice to hear it wasn't the spark plugs which is where some folks always start problem solving.

Not trying to be factious, but I would suspect it's easier to change plugs (knowing they aren't the easiest either). Hopefully this is a rarity. Can't imagine Weber doesn't know proper interference angles for a taper fit. It happens though, been thru this problem in the past and Loctite wasn't the solution, a temporary crutch at best.

Page 8.28 of the FST service manual:



Later. the alternator pulley bolt is torqued to 60 ft. lb. This secures the flywheel to the crankshaft.

The 60 ft lbs of torque and Loctite do no good what so ever unless the angles between parts are machined correctly so the pushing force of the capscrew causes a binding lock between the 2 parts. I understand what the manual says, that doesn't make it right if the parts are wrong. Hopefully parts are machined correctly and there won't be additional failures. This was just a fluke, I hope. Production problems do occur. Sorry I addressed the subject.

Well, there you go. This is the first motor I have ever heard that puts thread locker on a tapered shaft. Seems illogical to mate a machined tapered mating surface with something that will now prevent the two surfaces from making the machined contact.

Not saying it won't work, but it certainly is a new one for me.

well i have 21.4 miles on my sled and now it won't start. called canyonmotorsports and told dealer about it. He said to check ground wire because he saw one that the wire broke off. then he said there is a recall on the gears and that they would arrive as they are available. going to check it out tonight.

Which ground wire ?

That's all he said? and you have a sled that won't start.
Does it turn over?

good

ok i turned the key and the engine tried to start but wouldn't. I checked the ground wire from the battery to the frame(footwell) area. It felt tight. the dealer told me he saw an fst with 1400 miles on it that the ground wire broke off. That was not my problem. I held the throttle wide open and cranked it. then it started. It was flooded. I then held the throttle at about 2900 rpm for a minute. The sled sounded much better. If you start the fst and just let it idle it loads up. Holding the throttle wide open gives it more air and it will fire. just a little quirk that every model sled has i guess. :banana:

Glad you got it running. Sounds like more evidence that a computer reflash is needed. I'm convinced the sled is injecting way more fuel than is needed. Hence the bad MPG, starting problems, and fouled plugs.

Been thinking about the various posted and puting them together. I think the red hot exhaust is also a symptom of a rich condition. Extra fuel is burned in the exhaust. Unless you are running real hard on boost, the exhaust should be slightly cooler with a turbo because the turbo takes some of the heat energy out to spin the turbine. Fortunately I have not experienced the hot exhaust and my exhaust is clean and not sooty at all.
I'm contemplating adding an air fuel ratio gauge to see what's happening. Problem is I've added so many accessories so far I have run out of space. Still do have some space for a gauge on the left cowl panel. If I do I'll post what I see if we ever get snow again.

I believe you are right, that the fuel is very rich. Rich run is designed to run the engine cooler. Since the engine runs cool anyway, I think it was a precation that Polaris programed in to be sure they weren't stuck with a bunch of sleds overheating and wharping heads. Either Polaris will figure this out and send out a remap, or some aftermarket company will do it for them. My sleds run 150-155 in the snow, and there is lots of room for a lean up of this motor.