How long will a crankshaft last?

[Leftys]

I have no idea if the knock sensor has control over what your describing but it sounds like you might be experiencing the "detune" that happens when the water temp is more than 129.

Please explain what the "detune" mode is you are talking about. I have never heard of or noticed anything at that low of a temp.

 

[rmscustom]

Please explain what the "detune" mode is you are talking about. I have never heard of or noticed anything at that low of a temp.

Explained better than I could here by guys that are smarter. lol
post 43 and 45 are a good start.
http://www.snowest.com/forum/showthread.php?t=339282

 

[LoudHandle]

That's a strange one. They don't even offer one on their direct website. Maybe something they and Parts Unlimited have hooked up. If it is legit, it should be a good product.

I seem to recollect seeing one on their direct site, when this was first mentioned. The newer ones are listed by sled model rather than engine size. IE; PRO RMK, Rush, Switchback, etc.

 

[kiliki]

all this talk of deto so i have a question. does this motor have a knock sensor?
does it work?
is it set to low for the Geo theory to apply?

GEO YOUR INPUT?
i have asked this of you a few times now and you just avoid it...

 

[PaasoRacing]

I'm not GEO but Polaris motors have had knock sensors since at least 2004. I have at times even shimmed them with plastic washers to try to make them less sensitive.

 

[TRS]

The sled could be detonating and you would not experience running issues. The hammer is at work.
The ECU will adjust the map as it receives a det signal. When it dets outside of the control parameters of the ECU it will go into limp mode. When it goes into limp mode the "detonation correction limit has been reached". Code P1336 or P1337. Hope this puts a little light on the subject.

 

[kiliki]

The sled could be detonating and you would not experience running issues. The hammer is at work.
The ECU will adjust the map as it receives a det signal. When it dets outside of the control parameters of the ECU it will go into limp mode. When it goes into limp mode the "detonation correction limit has been reached". Code P1336 or P1337. Hope this puts a little light on the subject.

isn't this the same basic operation for all three makers of 800 2s? it just seems the poo has shown more of a problem with the rod bearing than the others. is this due to design or lower quality bearing choice? so to get to "detonation correction limit has been reached" most have taken away timing advancement along with adding fuel to the point the problem can not be corrected within the limits of the program.

 

[TRS]

Kiliki, yes the lower rod bearing on the Mape crank has issues compared to the Fuji crank. From what I have been shown, the Mape rod design, has a lot to do with the failures.

 

[ezra]

Does anyone have any experience with the Hotrods complete cranks?

I have never used on on a sled but turn a wrench when needed at a buds ski shop and hot rods are considered a mid grade crank in the ski world .
SBT are at the bottom of the scale
around my parts I am lucky enough to have a top shelf crank rebuilder who machines/ rebuilds with all top shelf bearings for less than a sbt exchange

 

[05900]

Longer than a Mexican Made french sled or Northern climate Feline jackshaft ?
Really how many check run out every time ya blow a belt? Lots of rentals ridden like they were stolen or east of the Mississippi dont know snow riders beatin on em.
Still goin ~ every little problem gets blown outa proportion here!

Is this a problem or did I get a great one AGAIN ? Are the vendors supplies to the manufacturer substandard and now we pay for it ? Or your Dealer ?
Hard to believe AC / Polaris / Ski Doo cant reverse engineer from the good engine companies..........

 

[geo]

GEO YOUR INPUT?
i have asked this of you a few times now and you just avoid it...

Sorry, lol. Didn't know I was in school.

Theshhold for det sensor has to be low enough not to be set off by all the other things that rattle around in and on a sled motor. You know: pistons, pins, exhaust, ex-valves, recoil, wieghts,,,.

The best crank in the world won't beat det but better material-treatments and more needles will prolong the inevitable.

Rod design changes to let more oil in is another thing completely. I waited patiently lol as Doo (early 800's) went around the world in rod design. Floating to tight shimming. No thrust to double thrust. Double slot to single slot to side inlet to everything above lol.
Why the learning curve? EPA. Cure? Electric oil pump and enough inputs to the engine management computer that you are almost flying by wire on a Doo today.

One thing most crank guys like to see in their motors is a small fishing pond of oil in the bottom. Probably because if you do something for living all week long, you don't want to be thrashing on Fri. night on you weekend warrior lol.



Slight det or big det lol, is easy to see on the tops of your pistons or piston.

Trouble is, it takes careful observation, from many experiences, while learning, with pyros and jetting down, to bring up temps, that keep going down, for unknown reasons lol, until, after a few mistakes, you hit your head with your torque wrench, skip a day of school, to test your new theory of jetting with pyros and learning that the piston tells all lol, to make it easy to see.

Best as I can describe how slight det looks Kiliki is, excessive wash (to prove you are safe) with the exhaust port width still dry and carbon crown receding slightly towards the center.
Hope it helps.