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Starter, Gears and One Way Clutch Inspection

grizztracks

Tech Advisor
Joined
Feb 24, 2005
Messages
3,110
Age
59
Location
Scio, NY
Country
USA
Snowmobile
FX Nytro RTX, RS Vector, SR Viper RTX SE
I have a low mileage 2005 RS Vector in the garage that came in with a starter issue and for a chain tensioner update.

The starter was still capable of starting the engine but it acted as if it was kicking out or skipping teeth on the gears. The starter was removed and a bench test performed which indicated that the starter worked but sounded a little rough so a new one was ordered. To inspect the gears the stator cover was removed but no obvious failures could be seen so the flywheel was removed to inspect the one way starter clutch. The hub on the flywheel gear that the clutch bearing locks to during startup had noticeable wear which I suspect was causing the problem so a new idler gear, idler gear pin, one way clutch and flywheel gear was also ordered.

When replacing any one of these starter component on the Yamaha 4-stroke engines I recommend that all the related parts are replaced. The good thing about replacing all the starer parts is that there have been updates to the gears to make them stronger.

Stator cover removed to inspect starter gears (flywheel also removed):
starter gear.jpg


Starter flywheel gear with a bad one way clutch hub:
IMG_5516.JPG


New updated idler gear. Notice that there are no webs in the gear and the teeth that the start motor's small gear runs on are now wider:
IMG_5514.JPG

IMG_5512.JPG


New updated one way clutch looks to be stronger than the old one:
IMG_5507.JPG

Old one way clutch installed on flywheel:
IMG_5509.JPG


New one way clutch installed on flywheel:
IMG_5510.JPG


I didn't notice any significant changes made to the large flywheel gear that locks to the one way clutch but I thought after all the Viper starter gear failures that Yamaha switched them all to chromoly for additional strength.
 
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Grizz could you pop the old One-Way out of housing. It should come out just pretty easy. Just spring loaded. Also the gear you show is a very different gear than has been in Vipers/Vectors since 14. But the part # is a new number even in the newer sleds. Just identical looking to new gear you have pictured. So there have been at least 3 different gears used in this engine. Good advice on new everything. How Much do parts cost though?
Here is both from a Viper. One on right failed.
DD9D64DB-C3CD-4415-83A0-10A62C427CDB.jpeg
 
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Yes, I can easily remove the one way roller cage from the mounting ring housing. Is there anything special you want me to look for there or did you want a picture of it apart? All the starter parts inside the stator cover ran about $275. Because the one way clutch caused wear on the hub of the large starter gear both the gear and clutch needed replaced so for an additional $60 it only made sense to update to the new idler gear.

With the way it was starting I really thought I'd find a bad gear in there. After finding no damage to the gears and seeing how the one way wore the hub I'm now thinking that the start problem was caused by the one way clutch not locking properly. It looks like it might have been chattering on the hub and that's why it sounded like it was skipping during a startup.
 
Yes, I can easily remove the one way roller cage from the mounting ring housing. Is there anything special you want me to look for there or did you want a picture of it apart? All the starter parts inside the stator cover ran about $275. Because the one way clutch caused wear on the hub of the large starter gear both the gear and clutch needed replaced so for an additional $60 it only made sense to update to the new idler gear.

With the way it was starting I really thought I'd find a bad gear in there. After finding no damage to the gears and seeing how the one way wore the hub I'm now thinking that the start problem was caused by the one way clutch not locking properly. It looks like it might have been chattering on the hub and that's why it sounded like it was skipping during a startup.
Yes a pic. Very familiar with these. If it has a small dia wound spring that’s usually source of issue. Any kinks in it the pawls will hang up on. Thank you! Never went in even that far on one.
 
Yes a pic. Very familiar with these. If it has a small dia wound spring that’s usually source of issue. Any kinks in it the pawls will hang up on. Thank you! Never went in even that far on one.

We should add this info to the RS, Nytro and Viper FAQ. The Apex motors are very similar but the motor will have to be pulled or lifted to get the mag cover off.
 
As cannondale27 suggested I took a closer look at the one way clutch. Before disassembling it I noticed a few stretched areas and one kink in the spring that holds the locking rollers in place. With it apart there's definitely some noticeable issues but what caused the failure in a relatively low mileage engine when there are many out there with a lot more trouble free miles?

IMG_5520.JPG
IMG_5521.JPG
 
As cannondale27 suggested I took a closer look at the one way clutch. Before disassembling it I noticed a few stretched areas and one kink in the spring that holds the locking rollers in place. With it apart there's definitely some noticeable issues but what caused the failure in a relatively low mileage engine when there are many out there with a lot more trouble free miles?

View attachment 134174 View attachment 134175
Holy cow! Never saw one that bad! I agree something out of norm happened here. Maybe the hub it grabs was soft?
 
We should add this info to the RS, Nytro and Viper FAQ. The Apex motors are very similar but the motor will have to be pulled or lifted to get the mag cover off.
I will add it if not done already when I get home.
 
Timely post...I’ve been searching for this info for two days and here it is. Anyway, my rage is free spinning the starter only when very cold, once warmed up all is good. It engages the engine and lets go so it’s quite the chore to get this thing started. Replacing these parts is a pretty big job, so I’m asking if indeed there is no other explanation other than failed components in this housing?

Looks like you didn’t pull the engine and the steering column is still there. How far did you have to go to access the housing? Do I need a puller to remove the stator as Yamaha recommends?

Maybe if you can outline the procedure on how you got to those parts that would be helpful. Again, I’ve been looking for a while but all I can find is conflicting information. Half the responses on similar problems is to clean the bendix! What bendix? Thanks in advance.
 
Timely post...I’ve been searching for this info for two days and here it is. Anyway, my rage is free spinning the starter only when very cold, once warmed up all is good. It engages the engine and lets go so it’s quite the chore to get this thing started. Replacing these parts is a pretty big job, so I’m asking if indeed there is no other explanation other than failed components in this housing?

Looks like you didn’t pull the engine and the steering column is still there. How far did you have to go to access the housing? Do I need a puller to remove the stator as Yamaha recommends?

Maybe if you can outline the procedure on how you got to those parts that would be helpful. Again, I’ve been looking for a while but all I can find is conflicting information. Half the responses on similar problems is to clean the bendix! What bendix? Thanks in advance.
I am going to vote for worn one-way bearing. Due to the heat changing it. Could be a out of phase starter but that would not change with temperature. I am afraid the OneWay is your issue. Just take your time,keep everything clean,take lots of pics and ask if you have any questions.
 
Never heard of an out of phase starter on these. Because the starter "free spins" I'd have to say starter gears or the one way clutch has failed. The one I took apart to replace parts acted as if it was skipping but would catch just enough to roll and start the engine. The starter in the sled was also bad but I went deeper because I was expecting to find a bad gear.

There are a couple tools needed like a harmonic balancer puller to remove the flywheel and a notched socket to turn the engine mount spacers. The first part of the process to get the stator cover off is similar to the cam chain tensioner procedure in the RS FAQ section. I believe there are discussions and possibly procedures for starter and stator replacements on these sleds also. I'll see if I can compile the information needed.
 
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Never heard of an out of phase starter on these. Because the starter "free spins" I'd have to say starter gears or the one way clutch has failed. The one I took apart to replace parts acted as if it was skipping but would catch just enough to roll and start the engine. The starter in the sled was also bad but I went deeper because I was expecting to find a bad gear.

There are a couple tools needed like a harmonic balancer puller to remove the flywheel and a notched socket to turn the engine mount spacers. The first part of the process to get the stator cover off is similar to the cam chain tensioner procedure in the RS FAQ section. I believe there are discussions and possibly procedures for starter and stator replacements on these sleds also. I'll see if I can compile the information needed.


Thanks, we’ve been in a deep freeze here - it warms up to -25c during the day. The sled is in my cargo trailer, I’ll move it back to the garage and see if I can limp it through the season. Too bad, I bought this “dealer serviced mint condition” sled from my boss sight unseen and so far blew a belt w cords wrapped around secondary, found the secondary ramps worn to the metal, while on the hoist I noticed all the front end bushings were bad, brakes were almost completely wore, battery was dead in cold weather and won’t hold a charge, reverse linkage was out of adjustment and periodically wouldn’t engage, and now this. I’m tired of working on this thing. Sold my warrior for this low km sled. Oh well. Just changed the oil w yammalube semi, about 20$ a bottle here, don’t really want to replace just yet lol.
 
Your sled is acting the same as mine did in 05. I nursed it through the season and took it back to the dealer in the spring. They changed the starter clutch under warrantee. They told me that it was the first one they had seen. I still have the Vector and have never had this issue again.
 


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