SKI-DOO Reimsliting ski doo 850 154’
- Trådstarter Vegardh91
- Startdato
Skjedde samme med min 17mod med alle opppdateringer. Reima var stramma slik den skulle og så helt ny ut før vi reiste opp på heia. Reima røyk/eksploderte i første bakken den dagen. Hadde da 200km på scooteren og mest løypekjøring...
Ser ut som at sekundæren er litt treig med å gire tilbake i forhold til primæren når man slipper speeden, da blir reima slakk og smeller i feste til variatordekselet..
Ser ut som at sekundæren er litt treig med å gire tilbake i forhold til primæren når man slipper speeden, da blir reima slakk og smeller i feste til variatordekselet..
Sist redigert:
En jeg kjenner har kjørt 700 km uten å ta en eneste reim med ganske hard kjøring.. tror det er veldig individuelt?
Kjørte 80 mil før første reim eksploderte.
Sjekka 1 mil før det sjedde og da var den strøken.
Så e nok noe som tar intill på et eller Anna vis.
Men ta bilde av reima! Jeg fikk det igjen på garanti, men da måtte brp ha bilde av reima.
Dette har jeg også trua på. I tillegg så går turtallet fort ned på 850 som det virker som det ikke er tatt høyde for dermed vobler reima siden sekundæren ikke følger med.
iBackshift.com & Dynamo joe har jobbet med p-drive variatorene i over 1 år..
han har hatt mange utfordringer med disse variatorene.
Men har klart å ta frem et kit som virker meget bra, ekstem bedre bachshift og går mye bedre med han variator kit.
Er vel få som kan disse variatorene bedre en dem.
Vi har levert en del kit til 850 og så langt er det ingen som har tatt reimer med dette kitet på, og tilbakemeld er at nu kjennes det ut som en 850 sier flere
han har hatt mange utfordringer med disse variatorene.
Men har klart å ta frem et kit som virker meget bra, ekstem bedre bachshift og går mye bedre med han variator kit.
Er vel få som kan disse variatorene bedre en dem.
Vi har levert en del kit til 850 og så langt er det ingen som har tatt reimer med dette kitet på, og tilbakemeld er at nu kjennes det ut som en 850 sier flere
Selv dem med DJ kitt skreller reimer på variatordeksel festet forran.
burde definitivt være en garantisak. Man bruker ikke så mye penger uten å forvente bedre levetid på slitedeler.
Kom over dette her på sledderz på facebook.
So I am getting tired of people calling my group of riding buddies a bunch of punks who don’t know anything about sleds, how to ride, what were doing wrong you name it we have heard it. Just because they’re all blowing up engines and belts daily.
So I am going to break down exactly my theory and many others on the 850 belt blowing, crank bearing, clutch heat issue whatever it is. Simply put math doesn’t lie. Not ever. Not if you’re an engineer at BRP. Not even if theres a fire. Math always tells the truth. ALWAYS. Take it or leave it. Its fairly simple.
So we start with an 850 stroker engine.
most people know that a stroker engine needs a balanced crankshaft to offset the placement in the engine to soak up vibration caused by the advanced stroke.
And I’m sure everyone by now has seen the bulletin that skidoo has released claiming they have in simple words “an engineered clutch wobble”
What is it? It is an inner primary sheave with anywhere from
.010” - .050” runout from the inside diameter to the outside. And yes. Every single one is that much different thats how inconsistent they are to begin with. This simply means that the sheave is pressed on and permanently warped. Yes I said warped. Meanwhile the outer sheave is straight as an arrow.
Now BRPs theory on this, simply to save weight rather than putting a balanced crank inside the engine. They can manipulate the offset by making the primary clutch offset to the engines advantage. In return losing vibration. They hope… now that the belt turning inside the clutch at full rpm moving with the runout in the sheave, it works with the offset in the engine. The vibration is gone! Well… BRP hopes.
This sounds even ridiculous on paper, but it works. but only with no other variables. How about belt stretch, belt wear, belt heat - rubber flexibility at different RPM constantly. Where are all of these variables thrown into play? No where! How about the heat that this whole thing even causes?
I mean people want an answer on why belts are blowing? Its simple when I belt reaches more then 240 degrees which is caused by this “offset clutch” that belt will fall apart. Glue melts. The belts delaminate. No belt can hold up to the heat which isn the root to the belt blowing, all caused by this “engineered clutch wobble” I have personally seen well over 300 degrees clutch temperatures. Nothing holds together at that temperature. And no there is no magic. Clutching fix, no one gives a shit if your Jesus or not. You don’t have anything that will fix it as long as that clutch “wobble” is still there.
So how come crank bearings, cranks, rods and everything is getting destroyed in these engines? Oh but they burn so much oil. How can they just blow up?
Let me tell you.
All bearings have tolerances and clearances. And if exceeded are a recipe for short term wear. Oil or not. But what if the tolerances aren’t exceeded? Well then what else is there?
Vibration. The vibration caused by the stroker engine is somewhat terminated by this clutch wobble. But actually its not. All those variable with the belt heat, stretch, malleability and so many others come into play. On paper yes it eliminates the stroker vibration. In theory…
But really it still creates enough vibration to wear bearing out short term, which most people know too much vibration is a bearing killer. every single bearing brand new has a small amount of walk. It has to move and rotate. And it needs tolerances to do so.
So lets throw this clutch spinning at 7900 RPM (what skidoo calls for) with an offset inner sheave and put a belt in it. the runout on these inner sheaves are bad enough that the belts at full rpm can run up to 0.30” higher on one side of the clutch than the other. So this clutch spinning at 7900 RPM with the belt. This belt grips and loses grip every single rotation at least twice. Maybe more who actually knows depending on the numbers. But it does move that much. So this belt gets grip and loses it about 15,800 times per minute or more given your running 7900 rpms.
The pressure levels on the crankshaft from this are off this charts. Not high pressure. But simply just bouncing back and forth. (Vibration) so yes this is vibrating the crankshaft.
Which is vibrating inside the Crankshaft bearing on the PTO side. So all of a sudden this bearing is getting way more vibration than it can handle long term. Those tight new tolerances turn into larger and larger ones over time. But theres still another variable. The clutch heat. The heat made on the primary clutch anywhere north of 240 degrees on the primary itself, gets transferred into the crankshaft. And into the bearing. Heat does crazy things. Expanding and shrinking as temperatures change. Heat kills all bearings. Every time. I don’t care if your uncle or grandfather or your cousin says it doesn’t. But it does. So what is 240 degrees?
Its really not a lot for a bearing. But throw the vibration into it with the small expansions and shrinking at random rates. And it makes for quick easy short term wear and eventually will wreck it.
Now I know a ton of people will accuse me of not knowing shit because they don’t want to believe this is true. But its quite simple in reality. Its the way it works and always has. Math doesn’t lie. il let you guys do the math.
Now why do I care so much? Well when I see almost all of my buddies on 850s not even wanting to ride to their maximum ability because they doing want to blow belts because lets face it, belts aren’t cheap! And not only that but all the testing and trying I’ve seen my group of friends do and spend thousands to try and figure this problem out. Only to figure out you can’t do anything because it is the design itself that is the problem.
People say ohh if your worrying about cost of belts you shouldn’t be riding…
Yeah well when your like us and work all off season as much as possible to take the winter off and do nothing but ride because its what we live for its all that we want to do, spending every last dime as average guys and girls just because we love to ride. Throwing thousands into the equation for belts is just ridiculous. This shouldn’t be an issue. We crossed this bridge years ago. All we want to do is ride our sleds and have fun and for some of us it costs $1 per KM in belts or even more. It takes the fun out of it. Too the point where some of us can’t even afford it and don’t even want to. Sledding is already expensive enough.
BRP fix your problems, and start backing it up. There is a problem and you need to fix it. This is just the start. Theres a bunch more of us that can be even louder on social media. Step up to the plate and fix your issues.
One mad off sledder, of many others.
So I am getting tired of people calling my group of riding buddies a bunch of punks who don’t know anything about sleds, how to ride, what were doing wrong you name it we have heard it. Just because they’re all blowing up engines and belts daily.
So I am going to break down exactly my theory and many others on the 850 belt blowing, crank bearing, clutch heat issue whatever it is. Simply put math doesn’t lie. Not ever. Not if you’re an engineer at BRP. Not even if theres a fire. Math always tells the truth. ALWAYS. Take it or leave it. Its fairly simple.
So we start with an 850 stroker engine.
most people know that a stroker engine needs a balanced crankshaft to offset the placement in the engine to soak up vibration caused by the advanced stroke.
And I’m sure everyone by now has seen the bulletin that skidoo has released claiming they have in simple words “an engineered clutch wobble”
What is it? It is an inner primary sheave with anywhere from
.010” - .050” runout from the inside diameter to the outside. And yes. Every single one is that much different thats how inconsistent they are to begin with. This simply means that the sheave is pressed on and permanently warped. Yes I said warped. Meanwhile the outer sheave is straight as an arrow.
Now BRPs theory on this, simply to save weight rather than putting a balanced crank inside the engine. They can manipulate the offset by making the primary clutch offset to the engines advantage. In return losing vibration. They hope… now that the belt turning inside the clutch at full rpm moving with the runout in the sheave, it works with the offset in the engine. The vibration is gone! Well… BRP hopes.
This sounds even ridiculous on paper, but it works. but only with no other variables. How about belt stretch, belt wear, belt heat - rubber flexibility at different RPM constantly. Where are all of these variables thrown into play? No where! How about the heat that this whole thing even causes?
I mean people want an answer on why belts are blowing? Its simple when I belt reaches more then 240 degrees which is caused by this “offset clutch” that belt will fall apart. Glue melts. The belts delaminate. No belt can hold up to the heat which isn the root to the belt blowing, all caused by this “engineered clutch wobble” I have personally seen well over 300 degrees clutch temperatures. Nothing holds together at that temperature. And no there is no magic. Clutching fix, no one gives a shit if your Jesus or not. You don’t have anything that will fix it as long as that clutch “wobble” is still there.
So how come crank bearings, cranks, rods and everything is getting destroyed in these engines? Oh but they burn so much oil. How can they just blow up?
Let me tell you.
All bearings have tolerances and clearances. And if exceeded are a recipe for short term wear. Oil or not. But what if the tolerances aren’t exceeded? Well then what else is there?
Vibration. The vibration caused by the stroker engine is somewhat terminated by this clutch wobble. But actually its not. All those variable with the belt heat, stretch, malleability and so many others come into play. On paper yes it eliminates the stroker vibration. In theory…
But really it still creates enough vibration to wear bearing out short term, which most people know too much vibration is a bearing killer. every single bearing brand new has a small amount of walk. It has to move and rotate. And it needs tolerances to do so.
So lets throw this clutch spinning at 7900 RPM (what skidoo calls for) with an offset inner sheave and put a belt in it. the runout on these inner sheaves are bad enough that the belts at full rpm can run up to 0.30” higher on one side of the clutch than the other. So this clutch spinning at 7900 RPM with the belt. This belt grips and loses grip every single rotation at least twice. Maybe more who actually knows depending on the numbers. But it does move that much. So this belt gets grip and loses it about 15,800 times per minute or more given your running 7900 rpms.
The pressure levels on the crankshaft from this are off this charts. Not high pressure. But simply just bouncing back and forth. (Vibration) so yes this is vibrating the crankshaft.
Which is vibrating inside the Crankshaft bearing on the PTO side. So all of a sudden this bearing is getting way more vibration than it can handle long term. Those tight new tolerances turn into larger and larger ones over time. But theres still another variable. The clutch heat. The heat made on the primary clutch anywhere north of 240 degrees on the primary itself, gets transferred into the crankshaft. And into the bearing. Heat does crazy things. Expanding and shrinking as temperatures change. Heat kills all bearings. Every time. I don’t care if your uncle or grandfather or your cousin says it doesn’t. But it does. So what is 240 degrees?
Its really not a lot for a bearing. But throw the vibration into it with the small expansions and shrinking at random rates. And it makes for quick easy short term wear and eventually will wreck it.
Now I know a ton of people will accuse me of not knowing shit because they don’t want to believe this is true. But its quite simple in reality. Its the way it works and always has. Math doesn’t lie. il let you guys do the math.
Now why do I care so much? Well when I see almost all of my buddies on 850s not even wanting to ride to their maximum ability because they doing want to blow belts because lets face it, belts aren’t cheap! And not only that but all the testing and trying I’ve seen my group of friends do and spend thousands to try and figure this problem out. Only to figure out you can’t do anything because it is the design itself that is the problem.
People say ohh if your worrying about cost of belts you shouldn’t be riding…
Yeah well when your like us and work all off season as much as possible to take the winter off and do nothing but ride because its what we live for its all that we want to do, spending every last dime as average guys and girls just because we love to ride. Throwing thousands into the equation for belts is just ridiculous. This shouldn’t be an issue. We crossed this bridge years ago. All we want to do is ride our sleds and have fun and for some of us it costs $1 per KM in belts or even more. It takes the fun out of it. Too the point where some of us can’t even afford it and don’t even want to. Sledding is already expensive enough.
BRP fix your problems, and start backing it up. There is a problem and you need to fix it. This is just the start. Theres a bunch more of us that can be even louder on social media. Step up to the plate and fix your issues.
One mad off sledder, of many others.
Reima vobler og tar i festet. Når man ser hvor god avstand det er opp til festet skjønner man at variatorene ikke klarer å holde reima i sjakk ved av og på gassen-kjøring. 850 motoren er i tillegg veldig "skarp" og reagerer tvert når man slipper gassen også. Her kunne sikkert BRP ha hjulpet situasjonen med en liten flash oppdatering slik at motoren ikke bakker ned så brått men hovedsakelig er det nok at variatorer ikke følger med. Noen kjører i tillegg veldig ujevnt og nøkkete som gjør saken verre. Når da scooteren er veldig lavt giret og reima ligger høyt oppe i primæren blir problemet enda større. Riktig giring og et variatoroppsett som er samstemt løser sikkert problemet...tror jeg. Er kommet til under 30% innkjøring på min nå og reima er strøken. Kjørt både fort på vann og sakte i skogen, lekt meg på bakrulla så mye jeg kan uten problemer. Dette med en Xtrim som BRP klarer å gire mer riktig.
Snakk med Diablo og prøv et kit fra han er mitt råd. De andre har sikkert gode kit de også men jeg tror ikke de har de riktig samme problemstillingene som vi ved 0-1000 moh har. Det er noe med folk som lager ting 500km unna deg kontra 5000km. De må ha høyere giring og variatoroppsett deretter fordi vi har rett og slett "full" effekt der hvor vi kjører. BRP forstår ikke dette av en eller annen grunn.
Snakk med Diablo og prøv et kit fra han er mitt råd. De andre har sikkert gode kit de også men jeg tror ikke de har de riktig samme problemstillingene som vi ved 0-1000 moh har. Det er noe med folk som lager ting 500km unna deg kontra 5000km. De må ha høyere giring og variatoroppsett deretter fordi vi har rett og slett "full" effekt der hvor vi kjører. BRP forstår ikke dette av en eller annen grunn.
Skjønner ikke hvorfor han trekker inn dette med "stroker engine", 850'en er en såkalt overkvadratisk motor som de fleste to taktere i dag, den er faktisk den mest overkvadratiske motoren pr nå tror jeg, det motsatte av en "stroker" motor som betyr at sylindervolum er økt ved å øke slaglengden og da slik at motoren blir underkvadratisk.
At primæren er en off set design er jeg også litt skeptisk til, liker ikke at noe som roterer ikke er symmetrisk men her velger jeg å tro at dette har Rotax/BRP kontroll på all den tid det er lite problemer med kortbeltingene. Det er mountain segmentet som sliter og jeg tror det er fordi variatorene ikke er samstemt. Det er mye effekt i 850'en og slike svakheter blir avslørt tvert.
850 er overkvadratisk, men mye nærmere kvadratisk enn 800 da det eneste de har endret på er slaglengden. Den har altså 82mm cylindre og 80,4mm slaglengde. Dette er faktisk mer en Polaris hadde på sine 900 motorer (som egentlig er 866) og den var bel kjent for å riste og spise reimer til frokost og mye av det samme som blir gjort nå hos ski-doo ble gjort da av Polaris (Sterkere reim som tålte mer varme osv). Mange poengterte dette når Ski-Doo lanserte 850ene og håpet de hadde en løsning på dette, det merkelige er jo at løsningen ser ut til å fungere for noen og ikke i det hele å det store for andre? Er kanskje tolleransene for store? kvalitetskontrollen for svak? Driver de eksperimentering med kundene for å finne ut hva som er best? Er problemet overdrevet slik som mange ting på nettet?. Regner med at de kommer med en løsning for det må koste enormt å gi nye reimer på Garanti hele tiden.
Det er vel ikke noe magisk som skjer rundt 850cc motorvolum som skulle tilsi at man får noe mer problemer med reim spising pga vibrasjoner. BB motorer har jo eksistert lenge med motorvolum mer enn 850 eller 866 for den saks skyld uten de samme problemene. Skal også nevnes at det er betydelig mindre vibrasjoner i 850 enn min forrige 800 e-tec.
Nei ikke selve volumet, men når du nærmer deg kvadratisk motor med lengre slaglengde. Big Bore har jo samme slaglengde og er borret opp for volum. 1000cc til AC var og en BB motor med 78mm slaglengde. Kanskje problemet da ligger i kvalitetskontrollen slik at noen får et bra balansert oppsett, mens andre et mindre balansert oppsett?
Jeg tror rett og slett bare variatoroppsettet er feil for våre forhold og 850'en er litt sær med at den stopper fort opp når man går av gassen. Når man ser under variatorene så ser man hvor lite plass det er mellom variatorene og chassis. Det er ingen slingringsmonn for reima hvis den vobler/slamrer så jeg tror det er absolutt kritisk at reima holdes stram til enhver tid. Henger ikke sekundæren med vil reima bli slank og ta i et eller annet. Vet ikke noe annen måte å finne helt ut hva som skjer enn å bruke high speed kamera og filme hvordan reim oppfører seg. Da ser man helt sikkert hva som skjer.
Jeg skrev her tidligere at reima kunne ta i når man f.eks gikk fort av gassen osv, og enda verre om man ikke strammet etter reima.....da sa du at du mente det hadde overhode ikke noe med at reimene gikk
Endret mening nå?
Nei fordi du kan ikke stramme reima. Det går rett og slett ikke an. Bare korrekt fjær og helix kan gjøre dette. Stramming av defleksjon kan ikke og vil ikke påvirke dette. Det er jo super enkelt å se selv. Helix forlater strammeringen straks du begynner å kjøre, fra da av kan du om så ta bort ringen uten at "reima vet det".Jeg skrev her tidligere at reima kunne ta i når man f.eks gikk fort av gassen osv, og enda verre om man ikke strammet etter reima.....da sa du at du mente det hadde overhode ikke noe med at reimene gikk
Endret mening nå?
Det er fjær og helix som holder reima stram når du går av gassen.
Nettopp og da er det jo ikke problemet oppstår. Jeg kan garantere at du kan stå i ro hundre år uten å smelle reima
Det er under kjøring og da når reima er lang ut i giringen at den kan ta i noe.
Det som hadde vært interessant å vite er om alle scootere vobler reima og at det er bare noe som skjer før eller senere under kjøring og at det er et designproblem at den kan ta tak i noe og dermed ødelegger reima?