Fastrax project Pro RMK

Since there are a few unknowns with the new Pro RMK and the shops turbo 800 Dragon has been sold we've decided to jump in and get a head start on our own version of a Pro RMK. We started by purchasing a Rush from Minnesota and with the help of a couple SW friends it is now in the shop and torn down. This first post is mainly teardown stuff but there are some good pics of the chassis to checkout and if you've ridden and looked at the new Pro Rmks you'll see some of the differences between these chassis. We intend to end up with a 162-174ish 2.5" track and are still pondering on the skidframe. We will be building a carbon fiber tunnel/running board set up for it and plan to use 163 RMK coolers.We have also already begun development of some unique carbon fiber body parts to address a few of the issues we already see. Along the way, we will detail the way we look at curing track clearance and approach angle issues and mod motor mounting issues in the hopes that some of what we learn can be applied to the 2011 RMK as well. We plan to sell the 600 that came in this sled and install an '08-'10 vintage CFI 700 or 800 along with a turbo while the techies sort out the new electronics in the 2011s! There will be a bunch of hurdles to cross along the way as usual and we'll do our best to keep you in the loop of what we are thinking.

The donor sled: a slightly used Rush purchased from a friendly cross country racer in Minnesota

<a href="http://s801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/?action=view&current=ftxprojectprormk001.jpg" target="_blank"><img src="http://i801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/ftxprojectprormk001.jpg" border="0" alt="The donor"></a>

Mag side view after partial teardown:

<a href="http://s801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/?action=view&current=ftxprojectprormk002.jpg" target="_blank"><img src="http://i801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/ftxprojectprormk002.jpg" border="0" alt="mag side"></a>

Pto side view after partial teardown:

<a href="http://s801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/?action=view&current=ftxprojectprormk003.jpg" target="_blank"><img src="http://i801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/ftxprojectprormk003.jpg" border="0" alt="pto side"></a>

front view after partial teardown:

<a href="http://s801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/?action=view&current=ftxprojectprormk005.jpg" target="_blank"><img src="http://i801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/ftxprojectprormk005.jpg" border="0" alt="front teardown"></a>

Another layer of bodywork gone now...you can really begin to see how much room is really in one of these bulkheads. I'm impressed with the cleanliness of the bulkhead assembly, the triangulation is smartly done and I can see that the components of the modular bulkhead would be very easy to replace if necessary.

<a href="http://s801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/?action=view&current=ftxprojectprormk004.jpg" target="_blank"><img src="http://i801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/ftxprojectprormk004.jpg" border="0" alt="another layer gone"></a>

Good thing all of this is going in the swapmeet...man what a hideous conglomeration!

<a href="http://s801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/?action=view&current=ftxprojectprormk006.jpg" target="_blank"><img src="http://i801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/ftxprojectprormk006.jpg" border="0" alt="butt ugly!"></a>

Well, we've just removed 80 lbs from our project(yes, 80 lbs right on the money as you see it!)

<a href="http://s801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/?action=view&current=ftxprojectprormk020.jpg" target="_blank"><img src="http://i801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/ftxprojectprormk020.jpg" border="0" alt="the Rush skid...quite a contraption!"></a>

If any of you have torn down an IQ RMK, this shot should tell you how much further down the motor is mounted in the Pro chassis!

<a href="http://s801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/?action=view&current=ftxprojectprormk008.jpg" target="_blank"><img src="http://i801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/ftxprojectprormk008.jpg" border="0" alt="intake detail"></a>

OK, now we are getting some where! harness and bars have been removed

<a href="http://s801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/?action=view&current=ftxprojectprormk009.jpg" target="_blank"><img src="http://i801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/ftxprojectprormk009.jpg" border="0" alt="another layer gone"></a>

Motors out (and for sale or trade!) and you can really see how much room there is to work with. The layout is nice and simple...

<a href="http://s801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/?action=view&current=ftxprojectprormk010.jpg" target="_blank"><img src="http://i801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/ftxprojectprormk010.jpg" border="0" alt="naked blushing chassis"></a>

Now, honestly at this point we could just build a new cooler, tail section and just put 'er back together but we don't work that way...gotta make it cooler than that!

<a href="http://s801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/?action=view&current=ftxprojectprormk011.jpg" target="_blank"><img src="http://i801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/ftxprojectprormk011.jpg" border="0" alt="now what?"></a>

Here's one of the big hurdles with this(Rush) chassis: with a 1.25" track and 8t 2.86 drivers we only have 1.25" of clearance! well that will just have to be addressed now won't it? Drop and roll here we come!

<a href="http://s801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/?action=view&current=ftxprojectprormk012.jpg" target="_blank"><img src="http://i801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/ftxprojectprormk012.jpg" border="0" alt="tunnel clearance or lack there of"></a>

Lots of triangulation goodness going on here:

<a href="http://s801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/?action=view&current=ftxprojectprormk017.jpg" target="_blank"><img src="http://i801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/ftxprojectprormk017.jpg" border="0" alt="bulkhead front detail"></a>

Not to sure how well this motor mounting arrangement will handle 200 or more h.p....I think we'll be addressing that as well in this build.

<a href="http://s801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/?action=view&current=ftxprojectprormk013.jpg" target="_blank"><img src="http://i801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/ftxprojectprormk013.jpg" border="0" alt="motor mount/side plate detail"></a>

Here are the rest of the motor mounts:

<a href="http://s801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/?action=view&current=ftxprojectprormk014.jpg" target="_blank"><img src="http://i801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/ftxprojectprormk014.jpg" border="0" alt="motor mount detail"></a>

Here is another area significantly different than the Pro RMK chassis. The Rush has a more traditional rider/steering location so we'll be looking into adapting the RMK parts onto this sled as they become available.

<a href="http://s801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/?action=view&current=ftxprojectprormk015.jpg" target="_blank"><img src="http://i801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/ftxprojectprormk015.jpg" border="0" alt="upper steering pyramid"></a>

Pile-o-parts...just what we need, more stuff to trip over through the summer!

<a href="http://s801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/?action=view&current=ftxprojectprormk021.jpg" target="_blank"><img src="http://i801.photobucket.com/albums/yy299/fastrax_photos/Fastrax%20Project%20Pro%20RMK/ftxprojectprormk021.jpg" border="0" alt="bodywork graveyard"></a>

We'll be pulling the tunnel off next and development of the new tunnel will begin...we'll keep you posted as things move along!

Got a few more minutes this week to finish teardown-loving how easy this design is to work on-approx 230 degrees from the mapp torch to release the glue and a handfull of rivets and bolts to remove then the whole works slid apart.


here's the other side-by the way...did not have to remove any self piercing rivets to pull the tunnel-nice to not have to deal with those miserable things!



Awwww, what a cute little tunnel...my feet are almost as long as the boards!



Next step...we need to create room for a big track by re locating the drive system-looks like we'll be in for a workout. This design uses a flange cast into the chaincase and it becomes a major part of the structure on the mag side...looks like a little creative engineering will be in order!



We're still waiting on coolers to begin the tunnel and hope to see them this week so we can continue.

Curt

Yep, it looks like we'll be able to make a simple cutting jig change and use these tunnel sides/boards on both the Pro RMK and the IQ RMK.

How many of you guys have had issues with snow coming through the footrest and onto the clutch? How about anyone having problems with snow not passing through the footwell and packing into it instead? any complaints either way?

I'm worried about the motor mounting for sure-its actually most similar to a Doo Rev and the mounts are very soft-torque stops will help but I have other plans. I'm working with Brad to get a billet motor plate built since he's done the rev plates already and my plan is to add 2 more mounts in addition to extra torque stops. The RMKs are the same design. Hopefully we'll be able to find some slightly firmer mounts as well.

Curt

Well, still don't have my coolers but have finally recieved word that they will be here in a couple days. Meanwhile, I spent a bunch of head scratchin' time on the drop and roll.



The stock Pro case would require an elaborate billet or cast relocation ring to retain the oem mounting design(and strength) along with a replacement bulkhead side with relocated mounting bosses. Along with all of that comes several templates and lots of cutting.
I looked at using the IQ RMK case since it's 5/8" longer to begin with and would only require about a 5/8-3/4" roll to create the room we need. The problem is that we would have to build a very custom billet cover to support the bearing and outboard brake assembly used on the Pro chassis along with custom relocation brackets for the caliper in addition to a fairly elaborate drop and roll kit that would require some machined parts of its own....sounds expensive to me. So, I had a nice chat with Robbie from Avid yesterday and he has agreed to produce an extended case/cover for us. The cost will be roughly the same but the end result will be far less work for the installer and the install will be cleaner. At the moment it looks like we'll do a 1" down and 1" back driveshaft relocation which will accomodate even a 3" track properly. My case should be in his hands tomorrow and I'll show the results as soon as I have the new case.

curt

Outlaw Addict said:

Holy crap after readin all that... if those little Post Its were on my sled, they would say "WTF were you thinking when you started this project?" and "Buy a gun to shoot myself" :boom:

Click to expand...

Which is exactly why I'm posting all of this-so all of you guys can see what kind of effort really goes into figuring this stuff out and turning it into a product. Days and sometimes weeks of time(not to mention coin) go into developing a single product and I thought it would be cool for everyone to see that sometimes there are bad ideas and resulting failures along the way to finding the best compromise for the end product. I think this will be an eye opener for a lot of people and hopefully a little insight into the way we think things out!

Curt

sledstew said:

AWESOME CURT , LOOKS LIKE YOUR CRUISIN RIGHT ALONG ON HER.

Click to expand...

Yeah Buddy! Does she look a little different than the last time you saw her?:face-icon-small-hap

polaris dude said:

Cool project! The only thing is why would you want to have to do all this fab work when you could wait 5 or 6 months for someone to roll their new pro-rmk and just use that?

Click to expand...

Because we are one of the shops that build drop and roll kits!:face-icon-small-sho This gives us a good head start instead of waiting for an RMK.