550 fan Jetting and burn-down issues....

[penguinpoo]

Back up top. Anyone able to expalin why a carb/engine is completely un responsive to massive jetting changes....?

You say there is a lot of vibration, excessive vibration can cause frothing in the fuel bowl, causing the jets to pick up a mixture of air and fuel. Past remedies have been such things as different compound intake boots, custom fuel bowls, hanging weights on carburetors to reduce vibration.

 

[Tom400CFI]

Tom, who the hell knows. It doesn't make mechanical sense. I know accs might modify some of the jetting changes, but that doesn't make sense either because accs modifys barometric pressure in the bowls. Are the engines you do the drastic main jet change in, in a stage of failure that contribute to the lack of jetting response? Can reeds minimize a jetting change, like you are seeing? How about ring blow by?

Yeah I know it doesn't make sense. I dont get it.

*None of our machines have ACCS

*Maybe (stage of failure), but they still compression test good (95 lbs) cold, warm and HOT. We' compression tested the sled in question at least 5 times recently b/c it does exhibit symptoms of a "tired" engine. No case leaks and crank is true too (180* out)

*Reeds? Not sure what you mean
*ring blow by, other than compression test or dissasembly, not sure how to test. I may give up and jsut rebuild it and try again.

oh and for the poster about vibration, this motor doesn't vibrate any more than any other motor that we have.

This is weird.

 

[gogglefurnace]

Reeds

I don't know when POO started to put reeds in these 550's i am assuming with the EDGE chassi. I have read on some other sites that users of this motor feel that the reeds might have something to do with the lean spot/overheat issues, especially when normal tuning procedures are not working. Some have even thought of reed mods and/or completely yanking them out. They are basically a check valve. What if???

 

[Tom400CFI]

Ahh. got ya. The reed were introduced w/the 550, when the 550 came out in '99. IOW, the 550 has always had cylinder reeds.

 

[brsacjab]

Hi! New to SnoWest, not to 550 burndowns. I have two 2004 trail tourings. Love the sleds, but engine s*cks...pistons and all.

On rebuild three in two years, have a friend that had one go down recently too.

Seems with all I've read here;

-Exhaust heat soaking the "cool" cooling air due to poor venting/shielding is the ultimate failure cause.
-The much wider piston skirt clearances had helped prevent the skuff to siezure problem when heat buildup is happening due to riding or ambient temp conditions.

I like the creative cooling air ducting seen in th is thread. Seems any Edge fan motor shoulda had something like these stock. Polaris obvisously thought there was a problem, because they fitted the Trail RMKs with pipe heat shields and a heat shield between the muffler and the cold air intake...

Has anybody tried ceramic coating the y/pipe/muffler?

Is there such a thing as a rental fleet cooling kit? or is that a rumor?

Any other cool air kits attempts that have worked for folks?

 

[mtnpull]

I've ran the polaris fans in my rental fleet about 3 years ago and had a number of burndowns. Another rental business who I am good friends with still have a fleet of polaris fans and they have dozens of burndowns every year. Two years ago I went with ski doo fans. I have 32, all with around 5k miles and I have only lost two motors and both were because of the oil pump failing. They are a much better design, handle better, and are overall a much better fan sled.

 

[brsacjab]

Jeezus, Tom, those are some pistons. I would keep them all and put them away in a box, along with your unusable cylinders. They would make a good going away present for the Polaris 550 motor director who works at Polaris.

For the prior guy who wanted to know, the Polaris part number for the 550 engine Oil Pump Return (bleed/vent) Kit is: 2203889

By the way, if you order a cool air ducting kit, it comes with one of the above. It comes with a molded plastic housing that bolts over the recoil housing (its a pita to put on, mine did not line up with the holes and I had to take a file to it), new mounting bolts, the oil pump kit, a heat shield for the y-pipe, and a new fuel pump bracket to mount to cooling duct. It also comes with 4 louvered vents, one for each side of the belly pan to evacuate hot air, one to place in the nose just under the bumper to direct cool air into the engine compartment, and 1 to mount on the cowl below the headlamp. This one lines up with the motors cooling duct intake. There is also a screen to go over the front louver, inside the pan, rivets, etc. There are instructions, but my kit did not include the template to cut the holes in either the pan or the hood. I had to copy a sled on my dealers floor. Polaris is basically trying to get the engine outside air for cooling, as well as evacuate hot air generated by the exhaust system from the engine compartment.
...

Hey Frostbit, is there a part number for this cool air ducting kit?

Anybody seen one? Pictures?

 

[brsacjab]

Here's the info;

More info including the Polaris tech tip(link), note that Tom400CFI has them running though an even wider piston skirt clearance than the Tech tip.

Info Dump begins

Fleet cold air duct, now standard part on 550 fan sleds
Polaris part# 1203766
view parts diagram
1 SKU: 1203766
SUBSTITUTED BY 2203829 [Fleet] 1 $151.05
2 SKU: 7518910
SCR-M6-1.0X75MM-HX/CP-SEMS-LK [Fleet] 5 $2.97
3 SKU: 5813306
FOIL-ENG/FAN DUCT,EDGE [Fleet] 1 $3.45
4 SKU: 5813346
FOIL-ENG/FAN DUCT,FR,EDGE [Fleet] 1 $2.97

Hood duct that works with above part.
Polaris part# 2633400
16 SKU: 5430958-070
GRILL,BLK,LOUVERED [Fleet] 1 $14.27
17 SKU: 7670009
PALNUT(10) [Fleet] 4 $2.97


550 oil self bleed kit, loop kit for oil pump retro fit, now standard on 550 engines
Polaris part# 2203889
search for that part number here
2203889 KIT-550 OIL PUMP RETURN $41.59


Polaris Team Tip S-04-09-02 info

It covers three areas. It calls for a change in the piston to cylinder wall clearance, it calls for the needle jets and jet needles to be changed and finally an adjustment to the air screw settings.

These are the recommended upgrades to the sled.

2 - Needle Jet Q-4 - Part Number 3130947 - $42.48
2 - Needle Jet 6BGY-41 - Part Number 3131592 $11.00

End info dump

 

[LRD]

LRD, i can't believe you are here. I have read all your posts on doo-talk, because i am a fan guy. You are a bada$$ when it comes to tuning and weight reduction. Did you read all of this thread? Tom did a good job of trying to figure out all of the probs with these sleds. I agree there is a hot spot at around half throttle under cruise, but i think there is more too it with these poo's. Have you ever run temps with your 550 doo under similar conditions as TOM did ealier in this post, and if so what were they? I think that the FUJI engine should be good for more, but it is not in the 550s. Quality control is always in the shadows, but what about engineering failure? All the micro tuning in the world will not make up for lack of cooling when it comes to longevity. Fan sleds should be able to play, work, and not go down. At least not from the factory. Maybe when a guy starts to tweak, the considerations of failure become more of a concern, but for hells sake a sled should be somewhat good from the factory. Tell us about some 550 doo meltdowns, are they simular? Or are there any at all? Does doo use the Mikuni oil pump? What carbs are on the doo? How are they setup? What about hood vents as per underhood heat management? What about heat shielding? This is perplexing, and i know you have done some serious work with these fans. What if FUJI just screwed it up on the 550 and BRP got it right? Maybe FUJI got it okay and POO screwed up on the EDGE cooling? Any help would be appreciated!!!

Sorry to take so long to notice you asked some questions. Been working 14 hours a day learning how to trade Forex to make up for the 15 K monthly hit our managed 401K's are suffering (very spooky times when your 63).

Reading more on here I would also say heat issues like others have said. Here is how I have made one off cooling ducts. Mock it up out of cardboard (picture framing mattboard works great), then cover with duct tape, then lay your fiberglass over it, the resin wouldn't stick to duct take and you can peel it and carboard out. Have also glued to together layers of poly insulation board and then carved to design, filled with body putty and either duct taped it or painted and waxed (this doesn't work as well, resin ALWAYs sticks pretty good).

I think the doo 550 heads are finned quite a bit more than the poo. Visual will tell and then weigh them, heavy wins in this contest for cooling.

Cylinder walls, when I bought my doo 550 fans I talked to Bill Cudney in Canada (well known doo performance shop) about the moly filled rings (bad doo problem) and he said something I had wondered about nikasil cylinder walls. Said the moly rings were not a problem in the 550 fan or little 600 liquid (500SS) BECAUSE they had cast iron cylinder walls and they cooled better than nikasil. I always wondered how well the heat flow was going through the nikasil to the aluminum. The other thing is your best cooking utensil is the good old cast iron. My thoughts are aluminum bare conducts heat real fast but its much lighter than cast iron so my guess is the cast iron will hold a bunch more heat than the equal volume of aluminum and then add the nikasil heat barrier and ........... I have thought the nikasil is a bean counter deal, takes a lot of work to set up (bore + hone) a cast iron cylnder/piston.

When I big bored my 550 to a 629 I went so far as too add on a second head on top of the original head. Cut a hole rectangular through the cooling shroud and the fins stuck up through it for free air cooling. I'll see if I copy some of the pics from doo talk of it. Don't reccommend, just nuts amount of work but it worked, it would really get hot, just as hot as the stock heads under neath it.

Good Luck

550 to 629 thread with pics of cooling head mod

http://www.dootalk.com/forums/index.php?showtopic=63557&st=15

 

[Tom400CFI]

Cylinder walls, when I bought my doo 550 fans I talked to Bill Cudney in Canada (well known doo performance shop) about the moly filled rings (bad doo problem) and he said something I had wondered about nikasil cylinder walls. Said the moly rings were not a problem in the 550 fan or little 600 liquid (500SS) BECAUSE they had cast iron cylinder walls and they cooled better than nikasil. I always wondered how well the heat flow was going through the nikasil to the aluminum. The other thing is your best cooking utensil is the good old cast iron. My thoughts are aluminum bare conducts heat real fast but its much lighter than cast iron so my guess is the cast iron will hold a bunch more heat than the equal volume of aluminum and then add the nikasil heat barrier and ........... I have thought the nikasil is a bean counter deal, takes a lot of work to set up (bore + hone) a cast iron cylnder/piston.

This is TOTALLY in line with my beliefs and interpretation of what we've witnessed. The introduction of the Nikasil cylinders brought a dramatic DECREASE in longevity at the same time. We have switch nearly, if not all of our machines back to an iron bore.
1. It seems to last longer for us
2. It allows us the ability to over bore ($50) rather than buy a new cylinder ($300+)
3. It gives us a much wider choice of piston selection.

I also agree that the move to Nikasil on this particular machine was a value driven initiative.

 

[akwolfman]

Local guy that is rebuilding lots of them is running a hose from a hole in the bulkhead/tunnel to the crank so cold air is hitting it.
Also putting the whole kit in.
He is also using spi pistons and having people run a premix for the life of the machine.
He has yet to have one come back.
Told me what he heard was the oil line on the mag side was getting hot and boiling.
The machines are used hard for towing a sled with wood,drums of fuel,water and spend a lot of time at the 30 mph range.

 

[Jakeski]

550F Final Fix ??

Seems this thread just died. Hey you guys, esp. Tom, did you find a final solution to the problem?

 

[gogglefurnace]

not dead, just had to sleep on it. you know jetboats, fishing, harley, summer beer, stuff like that. i was in my shop the other day and was looking at my mikuni super tuning manual and found some good stuff about needle jets and jet needles and their relative values to mid range engine performance. i'll sort it out and post later.

 

[gogglefurnace]

well here is what i got from the manual. i should probably scan it and post it but gotta figure that out. this all goes back to the mid range over heat, lack of cooling issue which seems to be the bulk of the meltdowns. this addresses the lean spot over heat crap. my 05 edge has a q-0 needle jet and a 6deh 11 needle on 3 e-clip setting with accs and 260 +250 mains. my 08 edge has 210 mains, no accs and q-0 needle jet and 6bgy-41 needle on 2-eclip setting. the needle jet system works from 1/4 throttle to 3/4 throttle with the biggest effect at 1/2 throttle. the flow characteristics of the needle jet are the higher the letter in the alphabet the higher the flow, also the following number increases the flow of the letter as the number gets bigger. on the needle the numbers and letters have the same basic effect except the first number is length, and then the letters following tell about the taper of the needle (top, middle, tip) with the end number meaningless. so the bigger the letter, the higher flow. so faults near the 1/4 throttle are adjusted by the first letter, 1/2 by the second letter and 3/4 throttle by the third. so you can see my 05 is richer at 1/4, leaner at 1/2 and leaner at 3/4 than my 08 except that the mains have to be taken into considerations, but the accs should be leaning it out about 3 sizes. the needle and needle jet will have a small effect at wide open throttle. earlier in this thread were the specs for the poo upgrade neddle kit and i believe the needle jet is to be a q-4 and the needle a 6bgy-41. this would make my 08 some richer in the mid range. and then the e-clip setting. compared to 3, 2 is 3-6% leaner at 1/4 throttle 5-8% at 1/2 and 3-6% at 3/4 throttle. 4 is the same only richer. and then the throttle valve cutaway. at 1/4 throttle a difference in .5 on the cutaway has a 10% effect on lean or rich and 5% at 1/2 throttle going to 0% at 3/4 throttle. mor cutaway = leaner. so it seems to me if there are lean issues at mid range but are okay at full a simple e-clip setting might be used or a change to richer needle and needle jet. it makes me wonder if a rich mid range could help. grant it you still need proper cooling, but there are a lot of things that play into longevity. this is one piece of the puzzle that i'm finally starting to get. i'm also curios about the needles/jets and cutaway of the gen-2's that didn't seem to have these problems

 

[mfox]

Ok, the sound you hear is me killing myself. Long story short... I was looking for a pair of sleds for my boys (16 & 15) and found 2 '07 550 Edge LX on craigslist. I checked the internet for problems with the 550 and found this thread back in August. I bought the sleds anyway. Now one of them is down (482 miles) with the mag side cylinder burnt. I thought that the later model would save me from the problems listed here with the '02-'06. Sleds are stock, and do appear to have additional heat sheilding on inside of hood, muffler. I haven't looked to see if these have the oil kit or additional louvered vents as mentioned here. But I am beside myself. My brother-in-law has it apart and he can see scraching on cylinder wall and possible piston damage. We will get it further apart this weekend to further assess the damages. I have some inquirys into a good Polaris machanic we know to get some more info, see if he sees anything from his end.

After the fix, I am going to work up some ducting, shown here, for the fan and probably run 100:1 in the next tank. Anything else I can do?

I will keep the board posted on progress.

Thanks for listening(reading)

Mike
Oakdale, MN

 

[gogglefurnace]

heat

my sleds are still hanging in there. 2200 miles on the 05, 800 on the 08. but remember these are trail rmk's. i have the vent in the front of the bellypan, on both sides rearward on the bellypan, and the exhaust shielding that came stock. i have set both e-clips one notch richer but only in the last 100 miles. the sleds run fine in the midrange with the added protection of being a little richer. my oil pump timing is slightly rich, and i seem to be using a quart to 10 gallons. ( 40:1). i run ves oil. i use reverse sparingly. i will jet the 08 one size richer than called for. mostly i'm running pretty hard keeping up with the liquids, but i also hang with the grandkid in the midrange of my sled quite abit. i'm the goto guy for towing disabled sleds or cargo because none of the liquids want to hurt their sleds. it kinda seems to me the trail rmk venting seems to be working and at the least every non rmk fan should have it. more cooling would be better also. ( the poo upgrade stuff) good luck:beer;:beer;

 

[GoldDig]

Updates?

I just bought two 2002 550 Super Sports....AFTER buying them I found out about these problems!

I am strongly thinking about getting the new duct kits, oil bleed kits and the hood ducts.

Any feedback on reliability from anyone who has done the upgrades?

Will the "fixes" fit on the 2002's?

Thanks in advance for your responses!

Rick

 

[brsacjab]

I've got one 2004 trail touring that is still running after one top end, it may simply be "loose" due to wear.

My other 2004 trail touring that grenaded AGAIN last winter, is awaiting a rebuilt crank (took out the rod bearing this time) will be ready shortly.

I almost choked when I looked up the prices for the air duct kit, and I do question how good it might be...so...

I took a page from this thread and bought parts to make my own. I bought a 8"x8' semi rigid duct and a "floor" duct that necks down to 12x3 for a "scoop". Also grabbed a roll of reflective metal duct tape.

I'll take pics on the install. Just did a quick "trial fit" last weekend, looking good. I plan on connecting the "scoop" to the lower wide oeing in the hood (inside), almost lines up perfectly. Then the duct will have an almost straight shot to the fan flywheel. I'll cut the duct "side" so that it covers engine cool air intake and use the heat tape to seal it.

So then, like any other fan out there, there will be a significant cool air duct feeding the engine from OUTSIDE the engine compartment.

Also, when looking, noticed that it would be pretty easy to also add a aluminum sheet to the frame rail that would separate exhaust can heat from the cool air intake.

 

[GoldDig]

Thanks BR,

Pics would be greatly appreciated. I got the sleds with super low milage..172 on one and 105 on the other.

Sent them to the local dealer to get them tuned up and given the once over, he said that they were "brand new" and I would like to keep them that way, at least for 3 or 4 thousand miles.

Not too concerned with cosmetics, reliabilty is the call! Will have my wife and daughter riding them too and really don't want them stranded on the trail!

I won't have them north until Presidents Day weekend so I have some time to build some new ducting.

Any thoughts on the oil recycle hose?

Thanks again,

Rick

PS- Mine came with the shielding between the pipes and the engines. Why they discontuned it is anyone's guess. $$$$$?

 

[wolverinefan]

Here is my story on the 550 motors.

I bought a 2005 trail touring used with 1500 miles on it in 2006. Engine broke a piston skirt after I rode it for 200 miles. After taking the engine apart, I found out that it already had a piston replaced. The cylinders were so worn that I had to bore it and put a new crank in it. The bearings on the crank were blue do the lack of oil. At that time I just figured that someone ran it out of oil. The cylinders were honed to the Polaris spec's and put back together. I currentyl have 4000 miles on the rebuild. I believe it lasted this long because I never ride it at a constant rpm at slow speeds.

After the problems I had with the 2005, I bought my wife a new 2006 trail touring in March of 2007. On New Years Day 2010 my wife lost power on hers with exactly 1000 mi on it. I got it running and rode it 10 miles back to the cabin. It ran great but the motor did not sound right. I pulled the carb's off and the mag piston had scoring. I contacted my dealer which had no clue about the problems with these motors. They did sell me a fan duct kit at cost and they contacted polaris which said to put the oil pump kit on and re-hone the cylinders. The cylinder that seized did not need to be bored, but the pto piston was blue from all the heat. I have a set of Wiseco pistons and was ready to put it back together until I checked the bearins on the crank. Mag bearing is bad. I am currently waiting for the bearing because it is on back order from Polaris. I looks like it will be mid February before I get i running again.

After everything that I have read and experienced, I beleive the problem originates from the exaust silencer being so close the the fan, which caused the pistons to swell and create more heat and then cause the oil pump to fail. My dad has a 2001 550 supersport in the edge chassis and has never had a problem. His sled does not have the two piece pipe and silencer on it and there is a lot of space between the pipe and the fan. I think the fan duct kit will help greatly. I plan on putting one on my 2005 after I compare engine temps.

P.S. I ride in Michigan.