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If Doo put a non-adjustable non-serviceable belt drive on their sleds everyone would make fun of them.
BRP Drivetrain update
- Thread starter Machinchouette
- Start date
If Doo put a non-adjustable non-serviceable belt drive on their sleds everyone would make fun of them.
Only ones advancing the industry? Step away from the cool aid.
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As they should! A belt drive without tensioner is an idiotic idea regardless of manufacturer! That Po has managed to get the belts to last as long as they apparently do is nothing short of a miracle and has probably cost them far more in time and manufacturing control than a simple tensioner would have cost.
....and for what a spare QD-belt cost here in Sweden you will get a complete chaincase or two on the used market...... I was considering a ProRMK but had I gone that way I would have got the 3" model with chaincase.
By the way, I rode an SKS 850 and a ProRMK 850 within two minutes of each other and I call Placebo effect on anybody that claims a major difference in feel of the sled as a result of the belt drive!
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Just to be clear, a tensioner on a belt is not to increase the tension and that is what happens when you add a tension to the stock Quickdrive system. The tensioner allows the use of a much longer belt that now can wrap around the top gear and the belt is run much looser. For Polaris to add the tensioner they would only gain belt life by changing to a longer belt that has more contact with the gears.
The TKI belt drives work very well on the G4 and it is definitely an upgrade . The fact is Doo guys don't typically do any mods. I really don't know why but they are typically an older crowd that just want to ride. I sell to all types of customers and this at least is true around Alberta.
Sorry for the diversion, back to the subject originally posted.
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Nothing on a sled chassis is made to a tolerance fine enough that there is no slack in the belt when there is no tensioner. A tiny bit of slack will let the belt rise a tad from the sprocket, and when the belt has left the sprocket just a tiny bit the drive sprocket, due to the half moon cog profile chosen in the QD, will start to try to push the belt even further out rather than to pull the belt along. In the case of the QD a mild spring loaded tensioner would make a big difference just by removing the slack, it doesn't have to put any real strain on the belt.
Ok how do I get involved
I owned three different Polaris RMKs with the belt drive, including the first year. I NEVER had a moments issue with the belt on any of them in four years of hard riding. There is no fix needed. If you are unable to feel the difference between the belt drive and chaincase models, it is probably best you bought a Doo. It is an immediately noticeable difference for most.
We should probably go back to talking about fixing the real problem on the G4...
Sincerely since there are many tangent topics being discuss here … I'd like to ask what is the real problem in your opinion?
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The problem is the lack of a .25 wobble in the secondary to match the primary???
DB,
I think it is an alignment issue caused by motor mounts that are too soft. I also think that fully shrouding the clutches is a mistake, doesn't allow enough airflow. Polaris has a similar motor mount issue, theirs just wear out and you lose rpm. Neither the Cat nor the Poo have heat issues though and I think the much more open area around the clutches is a huge help. Doo admits it is for noise reduction, I think that is a mistake. I think the fact that this is mostly a mtn sled issue bares out the fact that the mounts are allowing too much movement under longer duration high load conditions... Sincerely
I think it is an alignment issue caused by motor mounts that are too soft. I also think that fully shrouding the clutches is a mistake, doesn't allow enough airflow. Polaris has a similar motor mount issue, theirs just wear out and you lose rpm. Neither the Cat nor the Poo have heat issues though and I think the much more open area around the clutches is a huge help. Doo admits it is for noise reduction, I think that is a mistake. I think the fact that this is mostly a mtn sled issue bares out the fact that the mounts are allowing too much movement under longer duration high load conditions... Sincerely
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I think if the Poo is loosing rpm due to worn motor mounts, the belt is getting extremely hot. It's just a guess since I'm not on those sleds
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If you didn't have a problem with the first years QD then you might not ride as hard as you think and could just as well get a Yamaha :evil::heh::sorry:
The two sleds i rode last spring were prototype 850s, a 155" SKS and a 155" ProRMK and between those sleds I'm quite certain no one cold manage "to spot the QD". Honestly, the clutching on both sleds were horrible, (I blew the belt on the SKS just carving in a flat meadow), so that might be a reason a potential difference was lost.
As to BRPs belt eaters I'm hoping they have solved this because I have a Lynx 850 coming.
On the alignment discussion I find it very interesting to read all of the stuff GnR and Daag has written about the engine alignment issues under load and I will definitely order a measuring tool IF my sled turns out to have problems. However there are loads of people on this side of the pond that cured their troubles these past two winters by fitting the Heelclicker based Diablo clutch kit sold here in Scandinavia by Alta Racing Service in Norway. IF the major issue is alignment I don't understand how any "kit", however good, could cure that?
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The Polaris 900 had belt issues and clutch issues. To solve it was vented , reclutched , changed rubber on the mounts , and floated the secondary. Plus they went to a Kevlar belt Some mods were not Polaris recommended rather users her and other forums. Polaris solved the 900 (866) RMK by not selling it after 06. Polaris now has a new motor 850 and to get it to sell has to have a very long factory warranty … all because IMHO of the way the 900 owners were handled by Polaris.
My point is people remember how they were treated by the manufacturer.
I think if the Poo is loosing rpm due to worn motor mounts, the belt is getting extremely hot. It's just a guess since I'm not on those sleds
That may be however, they do not have a belt blowing issue like the 850 Doo. There is no factory campaign to fix it because none is needed. Polaris has a litany of quality control issues IMO but blowing belts due to excessive heat build up is not one of them.
and the point you missed trying to defend your "hard riding honor" was that the QD belt isn't a liability on those sleds, never has been. It also does not have nor need a factory campaign to fix...
I can definitely tell the difference between a QD Polaris and a chaincase model. My buddy still has his '14 Assault, and I rode it many times back to back with a '14 Pro. The drivetrain weight reduction, especially the reduced rotating mass is immediately noticeable IMO.
I disagree and I bet most would agree that there are no Quickdrives with loose belts. They are the exact opposite, made banjo tight. Even old belts are tight as they stretch very little and when the gears heat up they actually expand and tighten more. When you upgrade to a TKi belt drive you better lock your parking brake on the slightest incline or your sled rolls away. This does not happen with stock Quickdrive as it is tight enough to add roll resistance.
If it’s so tight and adds resistance to turning.... wouldn’t that mean that it’s costing efficiency?
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Biases that run deep
That's a good thing. The G4 850 was enough of a head ache to find the different causes that we don't need another one. There is something phenomenal that came out of the experience. We can now take a page from the G4 850 and apply it to any sled of any make and model. I spent years trying to get used clutches to work. I would try to get help from the aftermarket with what I was finding but was always told that I was overthinking it. I called them back a year after the G4 came out and was told it CAN'T WORK! Ya right.... Now it's my turn, they are overthinking it lol
Another wonderful thing that came out of the G4 850 is it weeded out the aftermarket companies who didn't understand as much as they thought they did. Most don't realize just how deep our biases can run if we don't keep them in check. Posting on a public forum helps a lot with this.
That's a good thing. The G4 850 was enough of a head ache to find the different causes that we don't need another one. There is something phenomenal that came out of the experience. We can now take a page from the G4 850 and apply it to any sled of any make and model. I spent years trying to get used clutches to work. I would try to get help from the aftermarket with what I was finding but was always told that I was overthinking it. I called them back a year after the G4 came out and was told it CAN'T WORK! Ya right.... Now it's my turn, they are overthinking it lol
Another wonderful thing that came out of the G4 850 is it weeded out the aftermarket companies who didn't understand as much as they thought they did. Most don't realize just how deep our biases can run if we don't keep them in check. Posting on a public forum helps a lot with this.
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Apparently you have trouble getting a joke, even though I have some understanding in you becoming offended to be called a potential Yamaha-rider :face-icon-small-hap
If the comparison you have done is to an Assault with the Competition track then there you have a difference much larger than anything related to Belt drive/chain case. The competition track is a power consumer of great magnitude.
..... And there must be thousands of posts made about people having trouble with, I admit, primarily the first year QD.
Admittedly the QD might have gotten some bad write ups depending more on drive shafts and other components than the belt drive itself.
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Where do Doo guys get this idea that skidoo invented anything and everything that has to do with snowmobiling?
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