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Hi, Folks,

I'm interested in a 950 and came across a video showing the front and rear drive pulley misalignment causing excesive wear on the transmission output splines - and I guess having to replace that part of the transmission - is / was this a common problem or more to a single production year???

Any other high wear items to be aware of?????

Any glaring deficiencies????
 

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This is a known issue that can effect all model years.
Not all bikes have had the issue.
It comes from the belt being over tightened at the factory or by someone else who may have replaced tires, etc. and over tightened the belt.
Lots of folks here have 950's and never had an issue.
If you are interested in a 950 check the pulleys and belt for abnormal side wear.
If you buy one also check the belt tension.
 

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Before you buy one from an individual, remove the front pully cover and see if it has a fine rust or silver colored dust on the pully and belt. This is a sign of abnormal wear.
 

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2001 Yamaha XVS650 Dragstar Classic and 1999 Honda NT650V Deauville
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I have read several topics on the matter here lately. And I must say I struggle to understand the mechanism that cause the increased wear on the splines. Usually, a too tight chain or belt will cause stress on the output shaft bearing and the crankcase. This can lead to a damaged bearing or, more often, an over-stressed crankcase, causing the hole for the output bearing to become oval and allowing the bearing to spin in the cases.

I will stick my neck out and say that to me, the most likely cause for the spline damage is faulty hardening, but I would love to be wrong and learn how a tight belt can kill the splines. The splines on the output shaft should not be more stressed than the splines on a shaft drive bike, the way I see it, and less than on a chain drive bike since the latter typically has a smaller interface between the narrower sprocket and shaft. And many sprockets on chain drive bikes are not even held by a bolt or nut, but just a locking ring that let the sprocket float.
 

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there's a thread in the engine forum (Transmission replacement. V-Star 950)
that is documenting the issue you're describing. i've seen tons of 950 owners document belt issues over the past decade including myself. this is probably the first i've seen that has caused this type of damage, if it is from an over-tightened belt. but the belt tension isn't necessarily the fault of a particular shop or owner. Yamaha themselves recommend a belt tension that most of us have come to realize is just too tight. they recommend 3mm-5mm of movement at 10 pounds but the sweet spot is closer to 7mm. people that have documented belt issues have seen those problems go away when they loosen up the belt.
 

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Thanks, bevo, I have read the discussion in the link you provided. I have tried to find more information around the interweb, and it seems that the Suzuki Savage and newer Harleys in particular also are affected. The concensus seem to be that any play/slop in the interface between the shaft and pully and/or a retaining nut/bolt not tight enough is the prime reason the splines goes. Several Harleys have been reported to eat a pully in less than 1,000 miles, and do so repeatedly until they also replace the output shaft - even if the shaft appeared to be flawless. Once they get a proper interface and the parts locked up solid, there appears to be no further issues. I have not found anybody discussing belt tightness as a possible culprit, but then again I have not read everything the web has to offer 😄

I have not found any reports on spline damage on BMWs or Kawasakis using belt final drive, but then again my searches may be flawed.
 

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When I’ve replaced the tires on my 950t and Monica’s 950, I make sure the belt is not overtightened as I’ve seen where others have had issues.
We, to date,have not had any issues and I check for proper belt wear. Let us know what you decide on.


Sent from my iPhone using Tapatalk
 

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The Can-Am Spyder guys have this issue as well and is where I picked up a lot of info on the subject. Also, the lateral load it puts on the pulley does indeed destroy the output shaft bearing/seal. I think the pulley splines start to deteriorate first, which provides enough slop and that enables the shaft splines to get eaten up as well. Some of the Can-Am guys would catch it in this state, swap the pulley and at that point add the loctite bearing mount to fill up any spline slop.


All this said, the 950 is super nice bike. As other have said, look out for the red dust on inspection and loosen the belt tension. Other than that there aren't really any other huge deal-breaker issues....that I know of.
 

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Has anybody tried to weld the sprocket to the shaft? It is not like they wear out every 20k miles like chain sprockets, so I could see someone saving a lot of time and some money and dig out a welder.
 

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I had and fixed the issue about 2 years ago on a 2015 950T.

At that time, the part number for the washer for the front pulley had been superseded. When I checked again about a month ago, only the new PN was listed. I am of the opinion that there were some of the washers that were not properly made (heat treated, probably) and failed to retain the required pressure on the front pulley. That washer is somewhat conical and also must be mounted with the correct side facing the pulley. (Basically, its a very stiff spring holding tension on that pulley against the shoulder on the output shaft.) The shaft is also harder than the pulley so If you catch the issue in time you can save the shaft. I replaced the pulley as I could feel just the slightest amount of play with the pulley on the shaft which explained the noise I heard that made me start investigating. The new pulley was solid (no play) and the noise went away.

Since then I have checked periodically for "red dust", and found none.

Item of note - from day one I never ran the belt as tight as the service manual says. I usually keep it at 10mm at 10 lbs and have no issues with belt slippage. Overtight belt may accelerate or exacerbate the problem, but I contend it is NOT the root cause.
 

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I realize its an older post but I'm thinking about buying a 950 and i own the lil brother 650. Love my shaft drive

IF i go look at one of these how can i tell if there is damage to the gear or pull shaft etc?
cant i run my finger under the housing to see if the red dust is present?
 

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If it is a dealer tell them you want them to remove the front pully cover so you can check it. If they want to sell a bike they will do it.
 

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If it is a dealer tell them you want them to remove the front pully cover so you can check it. If they want to sell a bike they will do it.
Thanx. but no dealers are costly. I'm looking to buy a nice used one from an individual.
Dealers are also known as stealers for a reason
 

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To answer your original question, look for rust colored dust on the front pulley. It's not so much misalignment that is the problem as the nut holding the front pulley on. Once upon a time, I thought I had it figured out but lately I'm not sure. Seems that if the bike makes it to 20K miles or so without an issue, it's good forever - or a reasonable lifetime and number of miles ~ 100K+.

My current leading theory: a few 950's made it out of the factory with a front pulley that doesn't stay tight. Maybe the nut wasn't properly torqued, maybe there's another reason, I really am not sure anymore. If caught early enough, tightening things to speck and maybe using some Loctite will prevent future issues. If left unfixed too long, the only fix is replacing the shaft and pulley which isn't cheap. And there are many levels in between.

Bottom line, If you find one with 10K+ miles that shows no signs of rust dust on the front pully, a 950 makes a fabulous ride (in my opinion). If the pulley area is too clean, I would be suspicious.
 
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To answer your original question, look for rust colored dust on the front pulley. It's not so much misalignment that is the problem as the nut holding the front pulley on. Once upon a time, I thought I had it figured out but lately I'm not sure. Seems that if the bike makes it to 20K miles or so without an issue, it's good forever - or a reasonable lifetime and number of miles ~ 100K+.

My current leading theory: a few 950's made it out of the factory with a front pulley that doesn't stay tight. Maybe the nut wasn't properly torqued, maybe there's another reason, I really am not sure anymore. If caught early enough, tightening things to speck and maybe using some Loctite will prevent future issues. If left unfixed too long, the only fix is replacing the shaft and pulley which isn't cheap. And there are many levels in between.

Bottom line, If you find one with 10K+ miles that shows no signs of rust dust on the front pully, a 950 makes a fabulous ride (in my opinion). If the pulley area is too clean, I would be suspicious.
My question was if you can see under the cover without removing it? Can you swipe under the cover to reveal the red dust? Its a pity that Yamamama dropped the shaft design
 

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I will have a look at mine this weekend. If you have one of these
105194
you may be able to see it although lighting may play a part in it. But you are correct nothing like a little red dust to sound an alarm....could be nothing more than a spline needed some lube or the bearing is fading fast. Maybe take q tip or something slim in case your fingers will not fit. I have a 950 and I really like it.
 

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I will have a look at mine this weekend. If you have one of these you may be able to see it although lighting may play a part in it. But you are correct nothing like a little red dust to sound an alarm....could be nothing more than a spline needed some lube or the bearing is fading fast. Maybe take q tip or something slim in case your fingers will not fit. I have a 950 and I really like it.
Thanks
i hate to buy one with 20k on it and not know if there is a problem. I've been readin about ways to prevent this issue form happening. I found one nice looking bike 2.5 hours away with belt issue. HE has priced reduced to !800.
its worth twice that fixed. I thought i about taking a chance and getting the pully welding.. Its probably best to find a good one tho. I dont know what kind of mess i'd get into
 

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It's best to remove that little chrome cover. Only 5 allen-head bolts and will give you a much better view.
 

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You can see and feel in between the cover and the pulley. (5) 5 mil bolts and the cover comes off. While I was there it took me a couple min to see unobstructed. Mine was in great shape. Hope you get to see before you buy it.
 
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You can see and feel in between the cover and the pulley. (5) 5 mil bolts and the cover comes off. While I was there it took me a couple min to see unobstructed. Mine was in great shape. Hope you get to see before you buy it.
I found two lovely 950's both 5.5 hours away under $4500, both with less than 5000 miles. Trying to decide on making a trip. As soon ass I buy one you know there will be a deal near me to come up. I have a good 650.. I dont want to lose the opportunity to move to he obsolete 950 with low miles. I dont like the newer Yamaha's.. Why no cruisers?
 
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