FCX Fan Cooled Xtreem CMX

Bushwacker1 · Apr 12, 2017

Merlin said:
Should be pretty sturdy when you're finished.

Are you going to run the P90 clutches from the 440 donor sled? If so, is the belt width similar to the Pro?

Not sure on the 440 but Aaen lists a 10lb weight savings with their 340 pipe.
That's substantial!

I have a few options on the clutches as I have P85 and P90 parts available. The P90 driven will require machining the jack shaft and I am not sure I want to do that. There is a belt width difference that would make using the set together the best idea. P90 1.25 width. Gen 2 era 1.375 and pro 1.437 ? You can do some spider shimming to get some versatility but I will need to work this out once I get the engine ready for placement and find out what center to center will be best for engine final position.

Still need to weigh the pipes.

Bushwacker1 · Apr 12, 2017

Had to take a few steps backward before moving forward. The big hole on the belt drive side of the tunnel that was filled in and exchanged for a nice small one resulted in a lack of clearance to install the drive shaft.

#1 No clearance to install. That is the bearing hitting on the bearing retainer. Did some material removal to the this bearing cup/ spacer. This will result in adding a shim on the opposite end of the shaft before the bearing goes on.
#2 Still not enough so a drill template was made to guide the hole saw to provide an egged shaped hole.
#3 Clipped the bottom of the clutch side bearing mount also, for more weight removal, and for some help to install shaft. Hydro formed shaft will fit now but it is dragging on the way in. New hole cut in for bottom drive pulley.
#4 Used the template to guide the hole saw to make a 2.5" hole on the tunnel portion only from the inside. Can not make this a thru hole as my bearing retainer does not have a retaining ring and the outer race of the bearing needs to have some bulkhead to rest against to insure the bearing stays in. It is a press fit, but better safe than sorry on that.
#5 Another view of the egged shaped hole that now allows the hydro-formed shaft to install with ease. The goal to minimize the size of the thru bulkhead holes as small as possible and keep a fair amount of metal across the bottom of the bulk head has been meet. Getting the drive shaft centerline to 7" from the top of the tunnel is where this has ended up and will provide as much clearance as the Pro RMK with a 1/2" cooler if water cooling an engine, and I should have more with the fan cooled engine. The newer pro style hydro formed shafts with the spedo inducer as part of the shaft will not fit without clipping off the inducer. I have one without that I think came out of a pro trail sled that fits but I am not sure what sled it came from. The hydro-formed 05 RMK shaft with the removable inducer is what I will be using. An extension will be made to bolt on after shaft install. This will extend thru the grease seal and have a fitting pressed in to pick up the right angle spedo drive link. The hope of using the large hex aluminum pro RMK drive shaft for now is no longer in the plan as it will require some redesign and most likely a large hole thru the bulkhead. This is not as much of a concern with the newer sleds with an over structure but these trailing arm sleds in my opinion need as much of the bulk head intact as possible for strength. Once final alignment for upper and lower shafts are completed the bearing retainer on the drive shaft (PTO side) will remain bolted in place and a track change out will not affect the critical alignment needed to keep the belt drive tracking straight.

Merlin · Apr 13, 2017

Kind of a catch 22. I think there are more helix options for the P85 secondary but the P90s are considerably smaller. Less rotating mass for the lower HP fanners is important IMO but I wonder what the difference in weight actually is between the P85 & P90 set ups?.

Bushwacker1 said:
I have a few options on the clutches as I have P85 and P90 parts available. The P90 driven will require machining the jack shaft and I am not sure I want to do that. There is a belt width difference that would make using the set together the best idea. P90 1.25 width. Gen 2 era 1.375 and pro 1.437 ? You can do some spider shimming to get some versatility but I will need to work this out once I get the engine ready for placement and find out what center to center will be best for engine final position.

Still need to weigh the pipes.

Bushwacker1 · May 7, 2017

Merlin said:
Kind of a catch 22. I think there are more helix options for the P85 secondary but the P90s are considerably smaller. Less rotating mass for the lower HP fanners is important IMO but I wonder what the difference in weight actually is between the P85 & P90 set ups?.

I weighed some clutches I have on a Harbor freight 70 Lb package scale. Both had weights and springs I them but not necessarily the correct ones. Did not have the attachment hardware in these weights either.

P-90 Drive 7.6875 Lbs
P-90 Driven 8.75 Lbs
Total 16.4375 Lbs

P-85 Drive 9.0625 Lbs
P-85 Team 4 bolt splined roller Driven 9.6 Lbs
Total 18.663 Lbs

P-85 set up will add 2.225 Lbs over the P-90. The 85 driven has a larger outside diameter which should improve the lowest starting ratio. Wider belt will also add a few oz. I thought it would be more of a difference than that. As this is rotating mass 2 lbs might be a big deal.

Bushwacker1 · May 7, 2017

Merlin said:
Not sure on the 440 but Aaen lists a 10lb weight savings with their 340 pipe.
That's substantial!

Finally weighed the stock pipe and the Aaen Pipe. Did not weigh any of the mount hardware. There may be some differences in the install by removing some of the stock brackets and fabricating of new mount brackets, may be some more weight to be saved there. Almost 6 lbs is huge. I am not certain where the sound level will be and that would be a no go if it is too loud.

Stock Pipe 13.25 Lbs
Aaen Pipe 7.375 Lbs

Aaen pipe is 5.875 Lbs lighter

Bushwacker1 · May 7, 2017

Still working on revising the install of the bottom drive shaft. I Keep revisiting a way to get the lightest stock hydro formed shaft, or the PRO large hex aluminum shaft to work. Currently the hydro formed shaft from a 2010 dragon is in the running with the Pro shaft being only a few oz lighter and that is if I run it without the collar. The 2005 RMK shaft is next heaviest but for my application will still be lighter that the Pro Hex shaft with a collar installed. The spacers that I am making to fit these shafts to my application are also a factor in the final weights. The wider hydro formed shafts from the 2010 dragon era are wider and have an aluminum end on the clutch side and will require a smaller spacer than a 2005 RMK hydro formed shaft that is shorter with the same type of aluminum end on the clutch side. Pro RMK hydro formed type are the same width as the 2005 RMK and have steel ends on both sides. Currently working on a revised bearing mount for the drive shaft clutch side that would allow more of the available shafts to be used. Will post more on this when I get something that will work better than what I have now.
*Also was considering an aluminum 7075 1.062 or 1.250 Hex shaft custom made that would be made to interchange with the Pro Dimensions. This would be the lightest option but I have received some input that it would need to be 1.25 hex to be durable enough.
*I was able to get a steel hex shaft tested and found that 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. Does any one know if they used a 1018 shaft for the needed strength and lower cost on 1.062 shafts and maybe 4140 for the light weight same strength 1" shafts?
*I did some digging on metal specs and found that 7075 aluminum comes up very close in listed strength PSI to 4140/ 4130 steel so would think an aluminum shaft of the same sizing would perform the same. There may be more to it than posted strength of these materials so if anyone has experience with the durability of 7075 custom shafts I would be interested to here how they hold up. This would be the lightest shaft/ driver assembly available if the durability is acceptable.

volcano buster · May 8, 2017

Will the P90 secondary give you enough clutching options?

I think the helix is smaller in diameter?

How about the shaft diameter? My spare P90 secondary looks like it uses a .75" shaft where the P85 uses a 1" (roughly) shaft.

Bushwacker1 · May 8, 2017

volcano buster said:
Will the P90 secondary give you enough clutching options?

I think the helix is smaller in diameter?

How about the shaft diameter? My spare P90 secondary looks like it uses a .75" shaft where the P85 uses a 1" (roughly) shaft.

The P 90 I have also has a smaller shaft diameter and would require cutting the shaft I am using down. I think the driven springs from all the old style driven's will work in the p 90 and there were many spring rates available but I would agree there probably are not many helix angles available. There may be some interchange from four wheelers that could have some steeper angles but I am not familiar with the four wheeler clutches. I am leaning toward using the team secondary and a p85 drive clutch.

volcano buster · May 9, 2017

Are the tapers the same on the P90 and P85 primaries?

I'm also thinking that the spare P90 setup I have came off a '92 which was direct drive versus the '94 which has a chaincase. The '94 may be a larger shaft but would have to pull the retaining bolt to see.

Bushwacker1 · May 9, 2017

volcano buster said:
Are the tapers the same on the P90 and P85 primaries?

I'm also thinking that the spare P90 setup I have came off a '92 which was direct drive versus the '94 which has a chaincase. The '94 may be a larger shaft but would have to pull the retaining bolt to see.

I sure hope they are the same. I have a new take off P85 that was from a Fuji twin I was hoping to use. I will need to do some checking on that.

For the Jackshafts the one I have is off a 92 Indy sport and is .750" with a keyway. I think the one on our 1999 Indy lite has a splined shaft.

Merlin · May 9, 2017

Thanks for taking the time to weigh that stuff! I thought there would've been more of a difference than that but 2+ lbs is still significant.

I'm not 100% sure but since a lot of that 2+ lbs of extra weight is a considerable distance from the axis, the effect on acceleration may be quite noticeable especially where HP is limited?

Also, very good point on the P85's having a lower starting ratio. That may negate, or possibly even surpass, any benefit to the lower inertia of the P90.

Bushwacker1 said:
I weighed some clutches I have on a Harbor freight 70 Lb package scale. Both had weights and springs I them but not necessarily the correct ones. Did not have the attachment hardware in these weights either.

P-90 Drive 7.6875 Lbs
P-90 Driven 8.75 Lbs
Total 16.4375 Lbs

P-85 Drive 9.0625 Lbs
P-85 Team 4 bolt splined roller Driven 9.6 Lbs
Total 18.663 Lbs

P-85 set up will add 2.225 Lbs over the P-90. The 85 driven has a larger outside diameter which should improve the lowest starting ratio. Wider belt will also add a few oz. I thought it would be more of a difference than that. As this is rotating mass 2 lbs might be a big deal.

Merlin · May 9, 2017

Did this sled come with the complete CMX drive system? If so, isn't that driveshaft aluminum?

Bushwacker1 said:
Still working on revising the install of the bottom drive shaft. I Keep revisiting a way to get the lightest stock hydro formed shaft, or the PRO large hex aluminum shaft to work. Currently the hydro formed shaft from a 2010 dragon is in the running with the Pro shaft being only a few oz lighter and that is if I run it without the collar. The 2005 RMK shaft is next heaviest but for my application will still be lighter that the Pro Hex shaft with a collar installed. The spacers that I am making to fit these shafts to my application are also a factor in the final weights. The wider hydro formed shafts from the 2010 dragon era are wider and have an aluminum end on the clutch side and will require a smaller spacer than a 2005 RMK hydro formed shaft that is shorter with the same type of aluminum end on the clutch side. Pro RMK hydro formed type are the same width as the 2005 RMK and have steel ends on both sides. Currently working on a revised bearing mount for the drive shaft clutch side that would allow more of the available shafts to be used. Will post more on this when I get something that will work better than what I have now.
*Also was considering an aluminum 7075 1.062 or 1.250 Hex shaft custom made that would be made to interchange with the Pro Dimensions. This would be the lightest option but I have received some input that it would need to be 1.25 hex to be durable enough.
*I was able to get a steel hex shaft tested and found that 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. Does any one know if they used a 1018 shaft for the needed strength and lower cost on 1.062 shafts and maybe 4140 for the light weight same strength 1" shafts?
*I did some digging on metal specs and found that 7075 aluminum comes up very close in listed strength PSI to 4140/ 4130 steel so would think an aluminum shaft of the same sizing would perform the same. There may be more to it than posted strength of these materials so if anyone has experience with the durability of 7075 custom shafts I would be interested to here how they hold up. This would be the lightest shaft/ driver assembly available if the durability is acceptable.

Bushwacker1 · May 10, 2017

Merlin said:
Did this sled come with the complete CMX drive system? If so, isn't that driveshaft aluminum?

Yes it had a cmx drive. His hub on the jackshaft would not allow me to mount a small enough sprocket to get to the ratio I wanted, so that is what started me down the path to build my own drive that would use as many stock parts as possible. The cmx uses a 1.25 Aluminum drive shaft but he bolts the bottom sprocket to the shaft. He starts with a shaft the same size as this hub and machines the rest of the shaft to a hex. This requires a lot of machining but is very strong. It also requires the bottom of the backplate and the bulk head to be open to be able to install the driveshaft. His plate is thicker and holds the bearings also. The thicker plate most likely makes up for any lost strength of having the bulkhead open to the bottom. Using the stock spline attachment method for the bottom pulley would be the weak point when changing from steel to aluminum. The info I have found on 4140 steel and 7075 aluminum shows that these are close in strength but I have found posts on other sites noting other considerations in engineering terms over my comprehension level that say it is not as simple as just looking at the commonly posted specs. This is why I posed the question, is there anyone out there that has tried an aluminum one that is made with the 25 mm bearing support and the 15 spline attachment point and to share how well it has held up. I am also looking at options to build a 1.25 aluninum shaft that would use the larger skidoo 27mm 17 spline with a 30 mm bearing. This would beef up the weak point but would require a new hub and bottom sprocket. Could not find any 52 mm x30 mm X 15mm bearings so a new bearing holder would be needed for that to work also. I did find a 27x52x15 bearing that may work if the skidoo spline is 27mm like I believe it to be, I could then make the shaft with a 27 mm bearing surface instead of the 30mm that skidoo uses. I need to get a skidoo shaft and measure the spline area. A 1.25 aluminum hex shaft looks like it would be just under 1 pound lighter (with the introvert drivers 3 inch pitch that I have available to weigh) when compared to a pro hollow hex shaft with a clamp installed. Not sure how that would weigh out if you had extroverts with the center driver. So much for using as many stock parts as possible. Change that to using as many stock parts as posible and some custom ones to make them work and some other custom ones that interchange with a stock part if the light weight one fails. I weighed this set up earlier in the build and it looked like I should be able to bring this in a little lighter than the CMX drive but this project has evolved so much from that so long ago time I will need to reweigh when it is finalized and done.

LoudHandle · May 10, 2017

Bushwacker1 said:
...I am also looking at options to build a 1.25 aluninum shaft that would use the larger skidoo 27mm 17 spline with a 30 mm bearing. ...

I can not confirm what the Doo spline is, but it is my belief, that the 17 Tooth spline form is actually 28mm major diameter.

The 17 Tooth spline that Yeti MX has used up until this production year is at least called a 28mm x 17 Tooth. The hubs I have from Yeti are actually slightly over 28mm (when measured to the major diameter of the spline at the two teeth nearest 180 degrees).

I would not have an issue with Shaving the 28mm x 17 Tooth spline form down to 27 mm for your build as you will have limited HP and Torque and will already have a far larger surface area contact than the 1" 15 tooth spline form.

Bushwacker1 · May 11, 2017

LoudHandle said:
I can not confirm what the Doo spline is, but it is my belief, that the 17 Tooth spline form is actually 28mm major diameter.

The 17 Tooth spline that Yeti MX has used up until this production year is at least called a 28mm x 17 Tooth. The hubs I have from Yeti are actually slightly over 28mm (when measured to the major diameter of the spline at the two teeth nearest 180 degrees).

I would not have an issue with Shaving the 28mm x 17 Tooth spline form down to 27 mm for your build as you will have limited HP and Torque and will already have a far larger surface area contact than the 1" 15 tooth spline form.

I will need to get a Ski doo shaft and measure. The one mm would most likely not be a huge factor but if possible I would want to build to the original specs. I did find a few other 52 mm of bearings in 28 and 29 mm bores but they are only 12 mm wide. The load ratings on these bearings are slightly lower than the standard rating of the 6205 bearing I am using for comparison. It may be better to use a bearing with a slightly lower load capacity than give up the strength on the weak shear point of this assembly. There are also some double wide bearings 52 X 30 x 20 and 22 I have found. They are air conditioning compressor bearings but I am having trouble finding any load ratings on these bearings to compare to the 6205 specs.

Merlin · May 12, 2017

Wow! Made from a chunk of billet. That helps to explain the cost of those drive systems. LOL

Reason I asked was if there was anyway to modify the CMX shaft to fit your application. Is the existing shaft too short with not enough material on the drive hub side for splines to be milled / broached?

Bushwacker1 said:
Yes it had a cmx drive. His hub on the jackshaft would not allow me to mount a small enough sprocket to get to the ratio I wanted, so that is what started me down the path to build my own drive that would use as many stock parts as possible. The cmx uses a 1.25 Aluminum drive shaft but he bolts the bottom sprocket to the shaft. He starts with a shaft the same size as this hub and machines the rest of the shaft to a hex. This requires a lot of machining but is very strong. It also requires the bottom of the backplate and the bulk head to be open to be able to install the driveshaft. His plate is thicker and holds the bearings also. The thicker plate most likely makes up for any lost strength of having the bulkhead open to the bottom. Using the stock spline attachment method for the bottom pulley would be the weak point when changing from steel to aluminum. The info I have found on 4140 steel and 7075 aluminum shows that these are close in strength but I have found posts on other sites noting other considerations in engineering terms over my comprehension level that say it is not as simple as just looking at the commonly posted specs. This is why I posed the question, is there anyone out there that has tried an aluminum one that is made with the 25 mm bearing support and the 15 spline attachment point and to share how well it has held up. I am also looking at options to build a 1.25 aluninum shaft that would use the larger skidoo 27mm 17 spline with a 30 mm bearing. This would beef up the weak point but would require a new hub and bottom sprocket. Could not find any 52 mm x30 mm X 15mm bearings so a new bearing holder would be needed for that to work also. I did find a 27x52x15 bearing that may work if the skidoo spline is 27mm like I believe it to be, I could then make the shaft with a 27 mm bearing surface instead of the 30mm that skidoo uses. I need to get a skidoo shaft and measure the spline area. A 1.25 aluminum hex shaft looks like it would be just under 1 pound lighter (with the introvert drivers 3 inch pitch that I have available to weigh) when compared to a pro hollow hex shaft with a clamp installed. Not sure how that would weigh out if you had extroverts with the center driver. So much for using as many stock parts as possible. Change that to using as many stock parts as posible and some custom ones to make them work and some other custom ones that interchange with a stock part if the light weight one fails. I weighed this set up earlier in the build and it looked like I should be able to bring this in a little lighter than the CMX drive but this project has evolved so much from that so long ago time I will need to reweigh when it is finalized and done.

Bushwacker1 · May 12, 2017

Merlin said:
Wow! Made from a chunk of billet. That helps to explain the cost of those drive systems. LOL

Reason I asked was if there was anyway to modify the CMX shaft to fit your application. Is the existing shaft too short with not enough material on the drive hub side for splines to be milled / broached?

The CMX drive shaft and bottom pulley was not why I went my own route. It was with the pulley size on the jackshaft. He has a left hand threaded hub on the end of his jackshaft that his pulley bolts to and it would have only been possible to make a new pulley one or two teeth smaller and still be able to get it on that hub. To get to the ratio I wanted I would need a much smaller top sprocket and most likely a larger bottom sprocket. There was an option to replace the jackshaft with a splined one and then use a smaller top sprocket but as his belt tensioner pulls out on the belt instead of pushes in (this is what Gates recommends) the amount of tooth contact on the smaller top pulley is minimized. As the CMX has the brake mounted between the pulleys and acts on the bottom pulley there is not much room to try and push the belt inward for belt tension, and none to put a larger bottom sprocket. Modifying the CMX shaft to have the splined end would be the same as starting with a new piece of hex shaft and would remove all the girth that CMX designed into the weak spot where the pulley connects to the shaft. The hub for the bottom sprocket is large and this is why the cut out in the tunnel is needed when installing a CMX drive. If you look close in the attached pictures of the CMX drive you will see a removable plate on the bottom of the back plate for removal and install of the drive shaft assembly. It seemed easier to just start over at the time and use as many stock parts as possible with the readily available TKI sprockets. Now as I am into several evolutions to get this the way I want, it says a lot for the aftermarket that can develop test and market product in such a sort time. I am not yet quitting my day job. I do have two of the CMK drives, if any one is interested just PM me.

Snowmixer · May 13, 2017

Merlin said:
If I could wave a magic wand & it existed, I'd like to have a 144" (3" pitch) track with 2" tall 2.4 series style lugs & lightweight construction for our Indy Lite. It'd be perfect! LOL

Any particular reason you want/need to stay with a 3.0" pitch track? If you were able to switch to 2.52, there is another option similar to what you mentioned above. It's a 144 (2.52 pitch) with 2" lugs, and 14" wide Camoplast "Maverick" that came stock on 2007-2018 Yamaha Phazer MTX models (picture below). It weighs about 46 pounds, and the 14" width supposedly makes it a little easier to get the sled leaned over, which could be helpful with a smaller rider. If the 2" lug is too tall, there is also a shorter lug version (can't remember the lug height...either 1.5" or 1.75") from the Phazer XTX.

Additionally, there is a Camoplast Challenger in 144 x 15 x 2.0 lug (2.52 pitch), item number 9875M. It just seems that there are several more track options available in 2.52 pitch, possibly more driver options as well, or at least smaller diameter drivers due to the closer pitch spacing.

Merlin · May 13, 2017

No particular allegiance to 3.0" pitch other than keeping things light.....

Thanks for the heads up on the Maverick 144"! Not being around Yamahas much, or at all, I hadn't even heard of that track before........I think I'd have went with it on our Indy Lite if I'd have known about it. 46 lbs is a respectable weight for a 144", 2.52" pitch track!

I think the 9875M would be good in the traction department but it's plenty heavy at 51lbs.

Snowmixer said:
Any particular reason you want/need to stay with a 3.0" pitch track? If you were able to switch to 2.52, there is another option similar to what you mentioned above. It's a 144 (2.52 pitch) with 2" lugs, and 14" wide Camoplast "Maverick" that came stock on 2007-2018 Yamaha Phazer MTX models (picture below). It weighs about 46 pounds, and the 14" width supposedly makes it a little easier to get the sled leaned over, which could be helpful with a smaller rider. If the 2" lug is too tall, there is also a shorter lug version (can't remember the lug height...either 1.5" or 1.75") from the Phazer XTX.

Additionally, there is a Camoplast Challenger in 144 x 15 x 2.0 lug (2.52 pitch), item number 9875M. It just seems that there are several more track options available in 2.52 pitch, possibly more driver options as well, or at least smaller diameter drivers due to the closer pitch spacing.

Reeb · May 16, 2017

I put a 141x2.25x15 3 pitch on my fan cooled mtn project years ago. I think it was called the 141 CE. The baby of the Camo Extreme lineup. It's very light and very capable of moving snow.

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FCX Fan Cooled Xtreem CMX

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