Sled repair

[Old Hubbard Rd]

I own 2 Polaris Indy Trail 550 or 500 not 100% sure. They were purchased new in 2000. One sled had about 1200 miles when a blew a head or piston. The other just happened with 2600 miles. What am I doing wrong?? I have owned other sleds (Yamaha Exciter) that I treated like crap and the thing always started and ran. These I treat so damn good. I just had them in at HK Power Sports in early January for tuneups etc. Spent almost $600 on both sleds hoping to have a nice riding season with no issues. I have noticed that each of these sleds are missing their top end. When I start them I can get 70 mph out of them but after rider for a while I notice top end is only 55-60 MPH. I do notice a bogging feeling at that high end after riding for some time. They are both air cooled which could be the problem. I have always used liquid cooled sleds. I'm getting old and I though my family would ride with me so elected to go to family style sleds. I was headed from Meredith to Alton Bay when I blew the head or piston on Fishing Derby weekend. I was riding it hard across the lake. Each time I blew the engine it was driving on the lake. Never have I had problems on the trails. I think the fact that on the trails you are throttling up and down therefore ingecting more oil into cylinders as when your on the lake there is less throttling. Let me know your thoughts and I hope HK gives me a reasonable quote for repair or where would you bring for repair?? HK mentioned that it could cost upward of $1500 although I gave them permission to break it down and give me a part list quote. Oh well!

P.S. Can't wait to get all the replys about buying another brand sled;)

[EricP]

I believe the high speed screws weren't adjusted properly, that would make sense as to killing them on the lake which is allows you to run WOT quite a lot. That trip to Alton Bay is 18 miles and we were moving pretty good the whole way. The spark plug that came out of the dead cylinder was dry and looked like it may have been running lean. We rarely get to run WOT on the trails so that would explain why you don't see a problem on the trails like you would on the lake. The only way to really test this is to do short runs WOT and then inspect the plugs to make sure they look good and the mixtures is good.

[jeffk]

IMHO cooling problems in today's sleds is one of the most irritating problems in the sport. I bought 3 new sleds a 6 years ago. Ski Doo 550 fan, 600 and 800 liquid cooled. I have had overheating problems with all of them. The fan cooled blew a piston under warranty. Part of the issue was a design problem with the temp sensors on the liquid cooleds which has been fixed but I still get overheats on 30 degree days on hard pack trails. It is simply ridiculous that Sleds have been completely redesigned from the snow up but still overheat.

I think part of the problem is the large engines. I never had problems with 340 or 440 fan or liquid cooled sleds. Further, they used to have combination liquid cooled that used both a air radiator and a track cooler. On ice or hard pack the air flow did most of the cooling. In snow the tunnel cooler worked better. The air radiator has been removed from most sleds. Maybe with the 550+ engines they just can't blow off heat fast enough unless conditions are optimal, lots of loose snow to cool for liquids.

As to your air cooled, I would guess it just can't handle sustained high speed, the air cooling just can't keep up with the heat demand. That is why sleds went to liquid cooling. Are you using a top oil, possibly synthetic to get the best lubrication and heat immunity possible? Are all the air paths clear and any filters clean? What octane gas are you using? Less octane less heat.

I'll be interested if any brands have no problems with over heating. I've always bought Ski Doo but this has driven me nuts. It affects about every second or third ride I take in some way. If another brand is rock solid under ALL conditions up to say 35 - 37 degree temperatures I'd probably consider that the next time I get new sleds.

[hazelnut]

P.S. Can't wait to get all the replys about buying another brand sled;)

I'd be disappointed to see anyone bash a certain model sled over this. I don't think one particular brand owns the rights to overheating and blown top ends. I've seen all types go down. We were with a group that had issues with Arctic Cat, Ski-Doo, etc. Yesterday a friend of a friends Ski-Doo blew up and the week before I believe it was an Arctic Cat that had the problems. So for one your choice in brand, Polaris is not a bad one it's probably a few issues that combined against you. Although I am no expert I'm wondering what oil you were using? I eagerly await to see what the expert mechanics on the forum tell you. In the meantime I saw a pretty sweet IQ Turbo Four-Stroke for sale at HK. It was a one up speedster. Had your name all over it. :laugh:

[SAMIAM]

Old Hubbard......I could have written thar post.....Same thing.Bought two new Polaris 550's from HKS in 2003 ....last year (right after service) my wifes machine blew an engine with 2000 miles on it and they quoted me $2700 to fix it.I threw the parts in a box and never went back.....they later tried to bill me for the ESTIMATE.
Machines were stored indoors and cared for perfectly.We were so bummed we haven't even fixed the sled and haven't ridden this year.I'll never go back to HKS.
Also a new neighbor moved in a few years ago that knew nothing about snowmobiles.They went to HKS and were sold a couple of dogs that nobody would buy......no electric start or mirrors.....carged them top dollar.
My son and his wife have two older Skidoo's that run beautiful year after year. Grrrrr

[tis]

I had one several years ago which we bought in the place in Tamworth sort of across from the state police. It was a Polaris (500? or 550? also). On the first ride out the engine died. I took it right back but to make a long story short, they got it going and I used it a couple more times just a few miles and the engine blew. They didn't want to do anything. They were just awful to deal with. Finally we knew someone who was the head of a big company and he just happened to be friends with the president of polaris and because and I believe ONLY because of that, did I end up getting a new sled. I got a 700 I think it was and it worked perfectly. I had to send the old one back. Polarise wanted to know what happened to it, but I never heard a word.

[VitaBene]

One of our 98 Polaris 500s is there now getting repaired. It went in with gearbox issues and some running issues on Thursday. They have done a great job in letting me know the status and costs. I should have it back before the weekend.

I am definitely not a dealership guy, I like small, independent shops. http://nhtoystore.com/

Good luck with your sled!

[PC31]

I also blew a piston but on a 600 Doo. They told me it was water in the gas when I had it fixed. In my opinion the ethanol in the gas is causing a lot of problems. All manufacturers sled are blowing up. Polaris is having a lot of issues with their 550 fan cooled. A friend of mine burned 2 pistons in as many weeks. This gas is not good for all small engines!! IMHO!

[Irrigation Guy]

One of our 98 Polaris 500s is there now getting repaired. It went in with gearbox issues and some running issues on Thursday. They have done a great job in letting me know the status and costs. I should have it back before the weekend.

I am definitely not a dealership guy, I like small, independent shops. http://nhtoystore.com/

Good luck with your sled!

Great guys to deal with!

[Seeker]

In my experience any sled can be a winner or a loser. I've been up north when all the fan-cooleds had their hoods up do to overheating on 35 to 40 degree days and when there was just minimal loosepack on the trails the liquids had problems. If you have carbs they need to be jetted for the conditions - but most never touch them and just luck out. I know it's a pain but stop and check your plugs condition once in awhile if you suspect problems. It's like taking your kids temperature.
If I don't have enough snow to kick up for my sleds heat exchanger and lubricate the sliders I don't go out.
I don't know anything about HKS but just be glad those idiots that owned the Arctic Cat/Polaris dealership in Ossipee where Canoe King now is are history. I was in there one day to buy a belt and 2 ladies came in to buy a brand new 2-up machine. The owner was too busy bs-ing on the phone with a buddy to even talk to them. I sent them to Rochester Motor Sports where they bought a new Arctic Cat tourer.

[jmen24]

2-strokes are very nervous dogs by design and need constant attention in certain areas, as mentioned in above posts. Not being a huge snowmobiler I am always facinated by how long you can go without having to rebuild the top end. Having 2-stoke bikes and quads in the entire range I have always rebuild the top end every winter on all rigs, not just the racers. I understand the work would not be fun on the big multi's, just has always puzzled me why it is not done more. As to particular makes, in the 2-stroke game the technology is all the same, it is very simple and not much can change from one manufacturer to the other, fit and finish tend to be the deciding factors, for me anyways, but they are all very picky and someone that says there brand is not, does not understand what a properly tuned 2-stroke sounds like. You can get bad years or designs in all models and makes in anything that is mass-produced. As mentioned above tune your carbs everyday to the conditions and you will have more fun more often and after doing this a few times you will start to hear and smell the right settings without spending to much time at it.

[hazelnut]

OHR,

Check this thread out on SledNH.com

http://www.slednh.com/forums/index.php?showtopic=3180&hl=

Looks like you are far from alone on this one

[trfour]

unfortunately or other, 2 strokes are as dependable as the owner of such, keeping them well tuned and "use their owners manual and or, Please, be a prudent consumer and purchase a repair manual", and study them, learn them so that you can ask questions at your dealership, about What does your tune up consist of.... spell it out to me!.... 1. Clean carb.... If you find a 10/4 inch of water in the carb bowl, do you drain the fuel tank, clean the fuel tank and fuel system so that my carbs do not fill right back up with water when you are done with your tune up??.... Dealer prep costs, depending on vehicle, lets say $200.00. I've been there too, got my $200.00 back, on more than one occasion after paying $20,000.00 for a new vehicle, bringing it home, putting on my coveralls and checking for myself, the oil level, almost two quarts low, transmission, 1 quart low, battery, 1/2 low.... After this, jacked the car up and checked differential, 3 pints low and then I really got POed, and I think that everyone knows howcome I like to take photos, and took them of the dry grease fittings along the way!.... Just one of the many reasons howcome I'm such a happy camper too this very day. :)


PS. Look Out FLL.

[Old Hubbard Rd]

Many thanks to your many comments. Sorry I have been away. This seems like a unfortunate consistant problem with these machines. I guess I'm not alone. I never realized how often this happened to people. I noticed that both times I blew something it was after Fishing Derby weekend and I had the family out on their 1 time a year sled ride. My family is pretty frightened of driving on the ice/lake. There are no trails from Meredith Neck to other trails without crossing the lake. When the famly drives they go rather slow and I really think these skeds need to be beat a tiny bit. I've never had problems on the trails because I think the continued throttling helps.

I'm sure Polaris and HK will do nothing about this even though I purchased these sleds there.

[chipj29]

...I'm sure Polaris and HK will do nothing about this even though I purchased these sleds there.

Both sleds are 2000 models? If that is the case, then I highly doubt any dealer or manufacturer would do anything.
That being said, someone else mentioned it above, but there has been a prob with the Polaris 550's. I read about it on slednh.com

[Smitty1]

I have a 2006 Ski Doo MXZ 550 Fan that blew a piston which then tore up more of the motor. I have a quote for about $2000 to repair.

This happened after I got gas in Holderness. It seems that ethanol gas/water is the problem.

FYI Here are 2 products I have heard of that may help with these issues:


http://www.k100fueltreatment.com/


http://mystarbrite.com/startron/

A friend of mine uses K100 in all his sleds and in his boat during the Summer.



Smitty1

[Old Hubbard Rd]

I have a 2006 Ski Doo MXZ 550 Fan that blew a piston which then tore up more of the motor. I have a quote for about $2000 to repair.

This happened after I got gas in Holderness. It seems that ethanol gas/water is the problem.

FYI Here are 2 products I have heard of that may help with these issues:


http://www.k100fueltreatment.com/


http://mystarbrite.com/startron/

A friend of mine uses K100 in all his sleds and in his boat during the Summer.



Smitty1

My last fuel up was at the Irving Station across from the Plymouth State/University field. Where did you fuel up??

I think that the new fuel with ethenol plays a part in this. HK said the inexpensive oil I'm using is not the issue. These sleds do tend to heat up I guess being fan cooled. Plus HK said that these fan cooled motors are not designed for speed so when I'm trying to keep up with others on wide open lake ride my sled is working harder than others. He also said something about running lower octane fuel as it burns cooler than high octane. Blowing a motor on our toys STINKS!!!!!!

[dan]

I'm not positive but I don't think the octane rating of the fuel has anything to do with it. (Octane rating does not relate to the energy content of the fuel (see heating value). It is only a measure of the fuel's tendency to burn rather than explode.) This is the definition of octane that I have seen many times. When buying gas we used to say, "if it don't knock burn it." I had a friend who was an aircraft mechanic during WWll who told me they used to water inject the radial engines when they were in a dog fight. Claimed it gave them more power but raised hell with the pistons. If this is true maybe moisture in the tank is causing it to run hotter.

[Smitty1]

My last fuel up was at the Irving Station across from the Plymouth State/University field. Where did you fuel up??

I think that the new fuel with ethenol plays a part in this. HK said the inexpensive oil I'm using is not the issue. These sleds do tend to heat up I guess being fan cooled. Plus HK said that these fan cooled motors are not designed for speed so when I'm trying to keep up with others on wide open lake ride my sled is working harder than others. He also said something about running lower octane fuel as it burns cooler than high octane. Blowing a motor on our toys STINKS!!!!!!


When you come down the hill out of Plymouth there is a Mobil and an Irving on the left. I wish I had gone to the Mobil!

[dragon7]

I have bought many of sleds from all three of the stores and have had nothing but good luck with the HK. I just blow up my Dragon 700 and they did everthing they could to help me get back on the trails as soon as they could and price to:)

[VitaBene]

One of our 98 Polaris 500s is there now getting repaired. It went in with gearbox issues and some running issues on Thursday. They have done a great job in letting me know the status and costs. I should have it back before the weekend.

I am definitely not a dealership guy, I like small, independent shops. http://nhtoystore.com/

Good luck with your sled!

We picked my son's sled up from Dennis a week or so back- they did a great job. I highly recommend Winnipesaukee Motorsports for your repair work.

Unfortunately, it will be going back before next season- Jr. sideswiped a non-moving object.

[Treerider]

Warm the engine before jumping on and tearing off into the sunset. Lots of burndowns are caused by an improperly (unheated up) engine, the jugs and pistons have to heat up before your rip out at 7500rpm.....5 minutes before you ride....longer in colder weather.

[MAXUM]

I've had to deal with this problem myself, I opted to rebuild my own engine and I'm glad I did.

Here's the real story, and BTW I posted a huge write up on this on HCS with all the technical details. So I will attempt to summarize this a bit.

In the 2004 model year Polaris was trying to squeeze as much power as they could out of the 550 fan cooled power plant. They did a number of things wrong that lead to a SLEW of people experiencing a catastrophic engine failure, either a seized engine or a melted down piston. Reasons why, the tolerance from the factory of piston to cylinder wall clearance was to tight. The throttle band had a lean spot between 1/4 and 1/2 throttle. The exhaust system muffler located right next to the air intake for the cooling fan was not insulated, the edge chassis design did not allow for enough air flow to keep the engine compartment cool enough.

So what did Polaris do to address this? Well first of all unless the sled blew it's engine within the first year of ownership (some did, others did not) they would not do anything to fix them. They changed the following items which includes all the way up to this year's model. I'll start from the oldest update though the latest.

-Changed the piston to wall clearance IF you use OEM pistons (I'll get to that later)
-Put out new specs for changing the main jets in both carbs, they spec differently between the two essentially creating an over richer mixture
-Put out a new spec for the jet needles, again jumping the size
-Put out a new spec for the needles and adjustment for the retention clips
-Put out a new spec for the air/fuel ratio adjustment on each carb
-Started to put insulation on the exhaust pipe with stainless steel covering
-recommended cutting a vent port in the front of the belly pan for better air circulation
-put on a new oil pump relocation kit which they claim fixes another problem of air pockets being created in the oil injection system at low RPM operation
-for rental fleet put out a new air intake system that has a dust that covers the air intake on the side of the engine and has a duct which must be installed in the hood of the sled. Got to cut a hole in the middle of the hood to install it, the idea I guess is to pull raw air from outside the engine compartment no doubt do to the lack of air flow through the belly pan during operation
-Came out either last year or this year with a new teflon coating that is supposed to help dissipate heat.
-This year they also added some new heat sheilds on the exhaust system and the air vent in the front of the belly pan is now standard.

OK so what does this all mean, well bottom line the engine has problems keeping cool and the lean jetting just makes it that much worse.

My engine melted down, I blew a hole through one of my pistons. Reason why I did the work my self, a big Polaris dealer (WILL NOT NAME NAMES) diagnosed the problem which is fine, but was only going to fix the bad piston and only bore that side if needed. I cannot believe a dealer of their stature would EVER consider doing something so irresponsible. OK I digress, I'm an ex mechanic and figured I'd tackle the job myself and that way I know it's done right.

First off the ENTIRE engine must be disassembled, anyone who suggests otherwise I would be hesitant to have them do the work. Secondly and I'm glad I had this conversation, the guy who did the machine work for me insisted that I consider using Weisco pistons versus OEMs, reason OEM Polaris pistions are cast which makes them inherently weaker and not necessarily uniform in regards to integrity. Weisco pistons are forged and milled so they are much stronger and of far better quality. The piston to wall clearance of the Weisco pistons are also greater than that of Polaris so it assists in keeping the potential of heat build up and seizure at a minimum. Along with the rejetting that cured my problems. I did cut a vent in the front of my belly pan. I only use synthetic 2 cycle oil and did slightly increase the oil flow to the engine.

My general observations are from 2000 when the 550 was introduced it was bullet proof. In 2004 to now the combination of engine tweaks from the factory and the fact the edge does not have as good air flow has been a huge problem. IF the engine is fixed correctly and enough air gets into the belly pan they are fine, IE put a vent in the front of the belly pan. If none of this has been done I would highly suggest you do or face blowing the engine. If you are looking at a used one be sure it's been modified per spec or you are buying a potential problem sled. I've seen enough of these go bad and talked to a TON of people due to my posting on HCS (hardcore sledder) who have asked me about the proper way to fix them. There is no reason to be scared of this engine but you've got to be 100% sure it's been fixed properly.

BTW if anyone is interested I do have my 04 2up 550 touring for sale. It's MINT and it's been fixed right. Not dumping it due to the engine, rather I'm about to buy another 1 up sled, don't need the 2up anymore.

Finally if anyone has any questions or wants more details feel free to contact me as I have a boat load of information to share. I've also been approached several times to rebuild these engines. The only problem with that is to do it right costs a lot of money, it set me back 1K between the machine shop and parts, and my labor of course was free. If I ever were to consider doing it I don't think I could do it at a competitive price, however I will say that it's not a complicated job and can be done by anyone with basic mechanical skills.

[ishoot308]

Warm the engine before jumping on and tearing off into the sunset. Lots of burndowns are caused by an improperly (unheated up) engine, the jugs and pistons have to heat up before your rip out at 7500rpm.....5 minutes before you ride....longer in colder weather.

Amen to that advice treerider! Thermal expansion in all engine components take place when going from super cold to warm and engine stress levels are much higher. Taking off at high RPMs in a cold engine is a great recipe for engine failure.

Dan