Yamaha Track Driver info needed

[Bushwacker1]

Looking for some involute 3" pitch drivers that fit a hex shaft. Not interested in extroverts as this is a very low H/P application. These would be used on a custom built 7075 shaft with Polaris spline on the sprocket end.
Would like to find Yamaha part # for 7 tooth and the 8 tooth.
I am not very familiar with Yamaha but have seen them on e bay used but would rather buy new parts or near new. I see that Yamaha offers these separate from the shaft but the on line info does not indicate tooth count or pitch.
Could anyone tell me what model sleds I would need to reference to get the part # for these drivers.
Also need to know if Yamaha uses a 1", 1-1/16", or a 1-1/4" hex shaft. Thanks for any help you can give.

 

[SNWMBL]

Edited due to posting misinformation. I will measure my 2008 Nytro driveshaft after work tonight.

 

[Snowmixer]

Are you sure about the Apex and Nytro shafts being 1.1875" hex? I have a 2007 Apex Mountain shaft here, and it is 1.0625. Maybe the 2011+ models are different? Also, I was thinking that I read somewhere the Nytro (2007-2013) shaft is actually a 30mm hex (1.1811"), though I doubt the difference would matter much...literally splitting hairs!


I also have shafts from a 2006 Nytro (similar to Vector, with 973cc engine) as well as 2007 and 2011 Phazers, all of which are 1.0625" hex. Looking at the handy "Snowmobile Track Fitment Guide" from Tracksusa.com, it seems that the only models (other than newer Vipers/Sidewinders, which use a much larger Arctic Cat hex) using 3.00 pitch are the Apex, Nytro, and Vector, all "mountain" models. I cannot confirm this, but as "mountain" models, I am thinking they are using 7-tooth drivers. I think the only way to know for sure would be to check in a service manual for those models, which I don't have. If you can find one, the info should be in there.


Looking at this parts schematic, http://www.yamahasportsplaza.com/oemparts/a/yam/5003c40af8700212fc84225d/track-drive-1 it looks like the driver you'd want is part # 8FS-47531-00-00 which had a price of $86.90 each. The funny thing about that number is that if I look at where it is used, it shows up on Apex, Vector and Nytro models, up to 2011. Either they are all using the same shaft size, or there is a lot more tolerance in how much the plastic driver will move to accept a different size shaft.


If you were interested in 8-tooth drivers, I noticed these new Wahl 8-tooth 3.0 pitch drivers on eBay for $79.00 each, free shipping. I know you said you are not interested in extroverts because it is a low horsepower machine, but if it were me...I'd probably use them anyway so that I could run the track a bit looser, freeing up any available power possible...since it's a low horsepower machine. Just another thought! Anyway, here's the link and hopefully this info was of some use!


http://www.ebay.com/itm/WAHL-BROS-N...ash=item2a614df7e8:g:2dkAAOSwx-9WvQ~1&vxp=mtr

 

[SNWMBL]

My 2008 Nytro driveshaft is 1.060"

 

[Bushwacker1]

Thanks for the info. I did end up on the tracks USA site to see what Yamaha's were listed as 3.0 pitch also. It was helpful but I would not have been able to determine the hex size without your help. So far it seems that 7 tooth are available from Yamaha for the 1.062 shaft but not any 8 tooth. Now on to researching for cat part # as I recall there was a few years that they made a 1000 cc triple with solid hex shaft and 3" pitch. I know this is the wrong address for cat info but if any one remembers which year and model that was please chime in. Thanks again for the info.

 

[Snowmixer]

I looked at a friend's 2005 M5 a while back, & was surprised to see that it had a larger hex, similar to what newer cats have (such as Pro Climb). I'm sure someone else knows better on this one, but maybe the smaller hex shafts were used on earlier models? I'm curious what your project is, any chance we'll see it in the "member sled builds" area someday?

 

[Bushwacker1]

Yes it is in the mod sled section. It is a project I started a long time ago and it is still not done. Started with a roller CMK that I wanted to put a fan cooled engine in for my kids to ride. Could not get the gear ratio I needed out of the CMX belt drive so I have been working on my own version that will be a few pounds lighter by using some pro RMK parts and some TKI sprockets. Lots of challenges along the way, not enough time, way too many design changes, and the desire to make even more changes to an existing proven design. It gives me a great appreciation to the aftermarket who design, test, build, and get performance parts into a box for sale while there is still a market to sell them too before a sled has been replaced by a newer model. It is easy to look at all the things that Mark came up with on the CMX and then say I can improve on it but getting those ideas to the paper and thru the machines and then on to the sled and prove it is lighter, just as strong, and actually works is the hard part. I am using a lot of Polaris pro parts and the basic body positioning of that sled to come up with a package that can be used to convert an old Indy air cooled chassis to a light weight mountain sled that a young rider can learn on. Hoping to be well bellow the 400 Lb mark. I did some research and found that a 7075 aluminum hex shaft would save close to one pound compared to the pro aluminum hex tube shaft. Does not seem like much but it will all add up in the end. For now I am fitting up a hydro formed shaft and will leave the aluminum hex shaft as an option to shave more weight in the future.

 

[Snowmixer]

Well that sounds like an excellent project! I'll have to find your build thread and check it out. I know how it is trying to find time for projects like this, but I do believe it will all be worth it when it's finished. I will be building a titanium track shaft for my sled sometime in the future, and intended to cut one out of 7075 aluminum first to make sure I had the process dialed in, but if the aluminum shaft turns out okay I may run that for a while just to see how it holds up.


I had always wondered about it, but wasn't sure if the splines would be strong enough. At some point I noticed Crazy Mountain was using an aluminum shaft, but I could never tell if they had splines on the end, or if it was flanged. With Arctic Cat switching to an aluminum shaft for 2018, I'm feeling even more confident that the aluminum hex shaft will hold up alright. I guess time will tell!


I've also thought it would be cool to make some sort of retrofit kit to be able to bolt on common modern parts such as A-arms (ideally stock parts that are commonly replaced with aftermarket) to an older chassis sled that originally came with a radius/trailing arm-type suspension. It may not make a huge difference in handling, but would be a much lighter package and though likely 'underpowered' by today's standards, would be great for those learn or on a budget.


Anyway, sounds like you've got some good plans, and I hope you are able to continue making progress on your build!

 

[Bushwacker1]

One of the criteria for my project was to use as many stock parts as possible so they could be easily sourced in the event of a break down. It also makes one less custom part that needs to made. What I have found is that finding used parts from newer sleds that are better/ lighter is the easy part. The challenge to adapt them is sometimes more work than starting from scratch. The adapter that I will be using to install a stock Pro drive shaft ended up weighing one pound. I am currently making mods to it to get that reduced. Once I get some prototypes built that meet my expectations and document the dimensions, making a few more will be much quicker.

CMX did use an aluminum track shaft. It has a hub on the pulley end with studs that are used to attach the belt drive sprocket to it. It looks like they started with round stock the size of the hub and then machined the shaft to a 1.25" hex to accept the drivers. The bottom of his back plate has a removable section in it so the shaft can be installed and removed when needed. His system is very well built and Mark told me he had guys running 200 plus horsepower thru his belt drives. I did some research and found that the properties of 7075 aluminum exceed 1018 steel. I would be interested to know what grade of steel the MFG's used for the 1.0625 hex shafts. My first thought is that 7075 would do just fine for a track shaft and would be lighter than titanium (cheaper also). Micro Belmont used to offer titanium jack and drive shafts but they were expensive. I found a site called on line metals that had some good info on the strength of metals. If anyone here has had experience with using an aluminum drive shaft please let us know how it worked out.

 

[Snowmixer]

Great information, thanks for sharing! After seeing the aluminum track shafts on the CMX sleds and reading that some were turbocharged, I figured that there must have been a fair amount of research or at least testing done to make sure the shaft would hold up.


As far as what grade of steel the manufacturers use on the 1.0625 hex shafts, I'm not sure, but it machines very easily, about like a cold-rolled 1018 would. I have a piece I cut off to shorten one of the shafts, I'll have a Rockwell test done on it one of these days. It won't tell us what type of steel it is, but my guess is that it is not heat treated, and likely something similar to 1018.


It has also been my suspicion that the steel hex was used mainly to keep costs down, not necessarily because it was needed for strength. At least that is what it seems like on my Yamaha, there are tons of parts made of steel that could have just as easily been made of aluminum for what their task is.

 

[Snowmixer]

Sorry it has taken so long to get back to you with some additional information! I had a chance to have the cut off end from a Yamaha hex axle Rockwell tested, and it checked out to having a hardness of 34 HRC (67.5 HRA), with a corresponding tensile strength of 152ksi/psi. In my opinion, a low or preliminary heat treat, or possibly something stronger such as 4130 that was not heat treated at all.


In comparison, a piece of 1018 steel tested too low to even register on the tensile chart with a hardness of 57 HRA.

 

[Bushwacker1]

Sorry it has taken so long to get back to you with some additional information! I had a chance to have the cut off end from a Yamaha hex axle Rockwell tested, and it checked out to having a hardness of 34 HRC (67.5 HRA), with a corresponding tensile strength of 152ksi/psi. In my opinion, a low or preliminary heat treat, or possibly something stronger such as 4130 that was not heat treated at all.


In comparison, a piece of 1018 steel tested too low to even register on the tensile chart with a hardness of 57 HRA.

I was able to get a steel hex shaft tested and the tester we had indicated it was made of 4140 or 4130 chrome molly. This was a one inch shaft that I bought at a swap meet and think it is a Polaris shaft. I assumed it was from an older Polaris as it was only 1" hex but then noticed it has the pressed on bearing on the clutch side which indicates it is newer (1998 or newer). I thought these newer styles were all 1.0625 hex but there must have been some differences. I have a 1.0625 hex that I will try to get tested but I am not sure when the testing equipment will be available again. Would still be interested to hear anyone who has run an aluminum shaft chime in on the durability, Hp levels, application, and their experience with an aluminum drive shaft.