Technical Overview of the IFS Liquifire Prototype

[JoeRainville]

Hi Guys,

Now that the 81 era Liquifire IFS Prototype has been shown in public, lets take a closer look at the details of this machine. These are obervations, and may not be 100% accurate. I would value any feed back from Horicon! A general picture of the sled on display at Waconia points out a few things:

The sled has a hood with 1981 decals, but the tunnel show stripes from 82.
It has a square headlight, a feature not seen until 1982 also.
Front bumper is not a Liquifire unit, but the thinner Trail/Sportfire type.
TPR side pannels are Trail/Sport also, you can see the silver pain under the flacking black.
The ski's look to modified regular Deere units with one having a reinforced tip.

[JoeRainville]

Under the right side of the hood we find more prototype parts aside from the struts:

Fabricated oil tank on the opposite side from stock, looks to be much larger, and it as a low oil sensor like what came out in the Sprintfire.
Just behind the chaincase, above the foot rest was a blank rivited on serial tag
Reshaped custom muffer to fit around the struts and sway bar
Stock looking fuel tank with the small inlet

[JoeRainville]

Here is the heart of the matter: The prototype strut assembly. This is not a motorcyle type strut as Yamaha used and Kawi built prototypes of. This unit contains a coil over shock to handle the shock loads and a structural sliding strut to locate the ski.
The knee action stearing arms are cut out of custom extruded aluminum.
The lower strut leg is steel, finished on centerless grinding.
The swaybar has special end linkage that preload the bar just from turning the bars. The keeps the sled flat in corners.
It appears the ski stance in narrower like the Trail/Sport to allow for the strut to fit under the hood. Not sure if that would have been changed for production since the sled is a few inches higher than stock.

[JoeRainville]

Underhood we find a mix of prototype and production hardware:
Stock 440cc Kawi Liquid Cooled motor, stock end mounts, but note the 82 HRS ignition.
Stock "dual cool" cooling system with radiator and bulkhead heat exchanger
Ports for measuring exhaust temperature on the manifold.
Modified Liquifire bulkhead with strut and sway bar mounts.

[JoeRainville]

The PTO side shows more prototype hardware:
TR800, it's matched driven and a wide M69170 belt. This set up was not available until 1982, and was offered as a "Wide Belt Kit" for the older Liquifires. Only the 82 version had a black cover.
Modifed clutch cover to allow access for belt installation/removal
Here you can also see the Polaris spec 34mm Mikuni's in place of the standard 36mm Power Jets. Stan Hays tells me it was built with 36mm PJ's, so this was likely done to attempt to get the sled running for Waconia.

[JoeRainville]

I found the rear skid to be one of more interesting parts of the machine. If the stock Liquifire had 6.5" of travel at the rear wheel, I am guessing this sled was about 8.5" or so. Production sleds didn't have that much travel until the late 80's early 90's. For example the AFS Cat's of 1985 had an industry leading 7.5" of travel.

The rails look the have a simular cross section to the Sprintfire. Note the front idler set does not required any external brackets to mount between the rails.
The front arm mount was raised to allow for more travel
The rear arm looks to be a Sprintfire type with the upper idlers mouted on the cross shaft. Note the Sprint had 7.2" of rear travel for 82-84.
This is the only Deere I have ever seen with a coil over shock on the front arm. Once dialed in, this should have been a good set up for mogals. Note the front arm is un-damped on the production Liquifires.
Notice the lack of drive lugs on the outer track belt? Track is also longer that the LF, at 121" vs 116 for the production sled.

[JoeRainville]

This view shows the rear arm set up on the Prototype. It still has the slider bock set up but appears to have some linkage on the shock.

Note the drive lugs on the center belt. Looks to be a 2.52" pitch also. This track also had wider slide rail center distances. Stan Hayes and Larry Swanson told me that was because it was the standard track they could get from Yokahma at the time. I never thought to ask why they didn't use the 78 Cross Country track, as it had the same 3.29" pitch and centers as the stock LF.

[JoeRainville]

This view of the front of the skid shows the covered coill over shock with an adjustable pre-load cam on it.
Note the taller cross section rail simular to what the new Direct Drive sleds recieved for 82-84.

[JoeRainville]

I hope everyone founds this interesting as I did. This was a great sled, and could have kept Deere in the game. As for why it wasn't built, I am told Deere chose to chase the lower end of the market with the Snow and Sprintfire and it's new engine instead of producing the IFS chassis and larger fan motor for the Sportfire. And so the story goes...

-Rainville

[Matt]

Thanks Joe, I was curious about the rear suspension, thanks for the explanation.

[AirborneX4Special]

Joe
It is indeed a shame this machine was not built, but Deere was getting out and it is likely the Sprintfire was built because it was cheaper than this would have been to build and sell. The commitment was gone, much to all of our chagrin. I had heard about this program via Stan's younger brothers right after the 80 Liquifire was introduced. Details were few, but that's how the game is played. It goes without saying I was very excited about the potential of an IFS Deere and this one was/is different than the " new and better Polaris " cookie cutter stuff produced today.

Thanks for all the work on the IFS Prototype; it has been fun to learn about it.

Pat

[TOYMECH]

Joe,

Nice job on the photos and report on the IFS machine. Thanks for taking the time to post all you did as i enjoyed reading the information posted as well as the photos.
I have to admit that you might be losing your touch a wee bit since the picture of the IFS sled in the back of a pickup leaving the show to go back to where it came from is not a familiar looking truck with NY plates...

Thanks to the others who posted as well.

-I should have went to Waconia..............

[EL DIABLO]

Great info Joe, and thanks for sharing!! I love reading about the history of these old sled. I agree with TOYMECH, I thought the ending to the Waconia story of the IFS Liquifire would have ended the the quote "and its all mine now!!"

Thanks again for all great pic and info!

[Dator76]

Hi Joe: great read, one thing ive heard about 81 liquifires is that a very few of the last ones built came with 82 parts. meaning square headlight, tr800 clutch, and 82 ignition. i think the parts book might show it or the service bullitens.

[S_Kyle]

I think I read somewhere around 107 of the late 81's. I think the serial had an "A" stamped after the serial number. Could be wrong but that's what I remember of it.