"What Ifs" On D-8 Burn Downs

TREE_MAGNET_777 · Dec 11, 2009

Don't know if this has been covered but, it seems like the 800's that have seized do it repeatidly, as did mine, and Polaris realy can't say (this is the problem) and it seems some ,not all are running a aftermarket pipe, and the ones running the pipe with a fuel controller last longer...sooooo IF (with the EPA restrictions) making the fuel map lean, and you throw in "maybe" some bad fuel, and a aftermarket pipe "maybe" leaning the fuel mix a bit and you are running right on the edge, and your voltage regulator has a hick-up that is intermitant. would that be enough to cause a problem "YES" . My theory is unless you stare at your head light or gauges 24/7 while riding you will not catch this glitch but it is enough to lean you down to scuff pistons. Now this is just my thoughts but if I was still running a d-8 I may look into it. Ride Safe...G

jim9006 · Dec 11, 2009

Since we're doing what if's.. I've not heard anyone with electric start having ECU issues.. Maybe if they all had a battery = problem solved?

KAWGRN · Dec 11, 2009

i bought 2 new regs and installed one and keeping the other in the trunk,,, sux that I have to do this !!!!!!!

thefullmonte · Dec 11, 2009

I think there can be a lot of variables that can contribute to this.
Excessive piston to cylinder clearance.
Plugged fuel filters
Faulty voltage regulators
Exhaust valves not opening soon enough
Lean conditions from EPA mapping
Air boxes not sealed properly
Insufficient cooling in critical areas
I feel all I can do is take every precaution I can. Which at this point includes:
Changing pistons
Adding a larger volume fuel filter as Skibreeze suggests
Make sure the voltage regulator is getting sufficient airflow. Relocate or add larger spacers to the module mounted on top of it.
Plugging exhaust valve bleed off hoses
Adding a fuel contoller
Seal air box.
Run engine ice coolant only!

TREE_MAGNET_777 · Dec 11, 2009

That is my thought exactly. However iF the voltage reg hick-ups on the trail but then returns to normal all of your problems COULD be traced back to that. I have chased electrical problems in my life, and changed everything hoping to fix it only to find out ALL the problems where do to one simple thing and there have been mutiple reg. problems.FYI cat runs its own voltage reg. in its fuel injection and has one for everything else. NOT BASHING just a observation...WHY, maybe they had this problem before and maybe not but from what I have gathered with one regulator IF it goes south YOU WILL LEAN DOWN. Hope like heck I am wrong and they have the fix as these are fun sleds to ride but this is just a ole Farmers thoughts...G

EricW · Dec 11, 2009

thefullmonte said:
Adding a larger volume fuel filter as Skibreeze suggests

Hadn't heard about a larger volume fuel filter. Whats the scoop? Thanks. EW

chumbilly1 · Dec 11, 2009

Not to bash ac but I towed a few early m-series out, and saw several that would not run above 6000 rpm due to a regulator issue, as i remember they did not have areg or something and if you smashed the light or gauges they would burn out the ecm. I have no headlight on my D8 I hope that isn't shortening the life of my electronics.

stmike · Dec 11, 2009

battery

jim9006 said:
Since we're doing what if's.. I've not heard anyone with electric start having ECU issues.. Maybe if they all had a battery = problem solved?

my sons 09 d8 switchback(electric start)ran like **** then burned the ECU,problem not solved.

Flit-e · Dec 11, 2009

skibreeze said:
I took another trip to Advance Auto and got exactly what I was looking for.
The filter is a purolator F64728 which has a 5/16" inlet and a 3/8" outlet. I also got a Dorman quick disconnect #800-054 which has a 5/6" connector and an @ 18" hose with a splice connector to splice into the stock upper hose. The filter has about 4 times the filter capacity and it is only $10, the Dorman piece is $20.

AK, the hose shop I went to earlier today didn't have any fuel injection fittings at all.

here is the filter set up with part #'s

TREE_MAGNET_777 · Dec 12, 2009

Not to say the filter thing might not help but don't you think if it was that simple Polaris would have figured it out??? Do they install a bigger filter on Turboed sleds that need more fuel?? here is one more case and point; Back in 00 or so I was riding a Doo highmark. Every ride it was hard starting and would run like crap untill it warmed up. I took it back to my dealer countless times and it always ran flawlessly for them. Other sleds had no problem either so they dissmissed as me being nuts (maybe). Come to find out the Brain Box or what ever it is, was farmed out to the lowest cost builder and they where useing a cheaper glue to build the boxes that when cold, would contract and break some connection in the box and once warm would reconnect. When my Dealer would check out the sled it stayed in a nice warm shop for the weekend and no problem Monday morning. All of a sudden I wasn't so Nut's. My Polaris Dealer informed me the voltage Regulators were specked out to one builder and the Bean counters found a way to save a buck and found a cheaper builder.... He also informed me My VR frying was one of many and Polaris hasn't hit that magic number to cause a concern. Fact Or Fiction I dont know just passing along what I have learned...G

Ps- if my sons are reading this please change my age to 50...real funny boys

Ron · Dec 12, 2009

Motorola makes the brain box-not a low bid mfct'r.

milehighassassin · Dec 12, 2009

Be carefull adding larger fuel filters to the sled. Many of them will have more restriction as well. I think changing out the filter each season might be a better idea.

TREE_MAGNET_777 · Dec 12, 2009

Thanks for the clarification Ron. I assume they also make the Voltage Reg??? Have you ever got a explanation on what has caused the piston scuffing. myself and some Polaris riding buds want to know...G

karnedge · Dec 12, 2009

i think iphone should have a app for that! lol sorry had to do it

rmkboxer · Dec 12, 2009

jim9006 said:
Since we're doing what if's.. I've not heard anyone with electric start having ECU issues.. Maybe if they all had a battery = problem solved?

see and people thought I got electric start because I was lazy

, I have not had any piston failures with mine but are the guys working on these sleds checking for air leaks and other issues or just putting a new top end on them and saying its bad pistons. I have seen some of the guys that work in these shops and wouldn't let them touch my lawn mower

jg442 · Dec 12, 2009

What if the single ring pistons don't transfer enough heat to the cylinder walls. I'm on my 3rd set of pistons and second set of everything else (Cyl, crank and cases, volt reg, head etc.) Pistons looked like they expanded from too much heat. I ride an '08 155 with 900 miles and am still waiting for the new piston and head update so we'll see if that solves the problem. My sled is stock except for venting and SLP can and I have never over heated the engine. I also have had no other running issues with the sled (midrange bog, etc.) Both times she let go I was riding mellow and there was plenty of pow for cooling. Hopefully the new pistons and head work because I love the sled, just not happy with the engine. Pistons and cyls. should outlast the belt! LOL

jim9006 · Dec 12, 2009

rmkboxer said:
see and people thought I got electric start because I was lazy, I have not had any piston failures with mine but are the guys working on these sleds checking for air leaks and other issues or just putting a new top end on them and saying its bad pistons. I have seen some of the guys that work in these shops and wouldn't let them touch my lawn mower

Actually I got electric start because I spent 30min last year up at Gallagher on my 2k 700rmk after a crash pull'n that rope to get it started again. I swore an oath that day to never again buy a sled with out electric start. And so shall it forever be for me!

Ron · Dec 12, 2009

TREE_MAGNET_777 said:
Thanks for the clarification Ron. I assume they also make the Voltage Reg??? Have you ever got a explanation on what has caused the piston scuffing. myself and some Polaris riding buds want to know...G

I don't know for certain but the fuel map may have been the straw.... Since failures in our area were almost non existent on sales of over 200 800's it would seem to be something related to the lean condition at lower R's, maybe worse at some elevations. Excess piston to cylinder clearance and the single ring let the piston rock in the cylinder so the piston skirts would have failed if the pistons hadn't scuffed first.
Many of us ran RedLine oil that had better tolerance to heat than VES Gold-Polaris has a new VES for 2010 with better lubricity, maybe better now than Redline. When engine heat exceeds the oils "lubricity" level then you will have sticking.
Then factor in all the little things: Some dealers didn't set the TPS during sled setup making fuel delivery more of an issue. Any direct short in the elctrical (handlebar heaters for one) will fry the ECU. Bad fuel, ethanol fuel in some locations-heard a story of an Ethanol purchase in a small town that had 20% alcohol-burned down several sleds. Blending alcohol into gas is subject to error and then you have phase seperation after a few months.
My 2009 was ported, head milled to raise compression 15% and SLP single pipe. Big air intake, holes drilled in the airbox shelf, speedo air added and running the stock 08 map-my sled ran spot on all year in spite of mods that should have put it on the "edge". I had a lot of piston rattle so had a ticking time bomb ala piston skirts.
Looking at the changes Polaris made for 2010 likely tell most of the story. Better VES oil; new fuel map; ECU will go into limp mode didn't in 09; double ring piston with normal piston to cylinder clearance; head has new dome shape, lower compression; longer sleeve on cylinders.

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"What Ifs" On D-8 Burn Downs

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