79 trailfire track conversion

[AaronLishman]

Hello,
Please excuse my ignorance as I am a snowmobile mechanic neophite. I have a 79 trailfire 340 that was gifted to me years ago, it has been a great fun machine, and i have taken it everywhere. Last year the metal track bars (cleats?) started to come off, one split one side of the track quite badly. I found and bought a 79 440 with a good cowl and track to replace it. after taking the old track off and putting the 440 track on I realized it was too long! noticed that the 440 had holes drilled in the tunnel 1.5 inches back, so I drilled some new holes on the 340 and moved the suspension back. now the track fits fine, but I just realized that the drive wheels on the 440 have 10 teeth and the ones on the 340 have only 8, so now they don't line up... major frustration, will have to take it apart and change the driveshaft (stupid , I should have noticed when I had it apart the first time..) I cant believe they are so different, the drive shaft on the 340 is hex shaped and the 440 is round. I would like to put a rubber track on this machine, and I did look at the FAQ, but came away more confused. I believe most modern tracks are universal, is this true? I have an old indy with a good track, but it looks like the drive wheels are in the center, can I just move the drive wheels to align with the track? I just don't want to spend more time on this than necessary. Any advice would be appreciated.
cheers -Aaron

[Matt]

It sounds like someone had already done a track conversion on the donor chassis. If it's a cleated track as well, It's probably from a 80-82 Sportfire or newer 80+ Trailfire.

There definitely aren't any universal tracks. As you found out, there are many variations of length, width, drive pitch, and rail spacing. You're best bet for a rubber track while keeping the stock style suspension is a Liquifire rubber track, drive shaft, and suspension.

[manitobatrailfires]

I'm not sure your track is from a JD. I thought at least all of the Fire Series sleds had hexagonal drive axles?

If the track fit under your donor sled, you will probably be able to swap out the drive axle and get it to work in your TF. I'd carefully ensure there were no other differences between your suspension and the donor sled though. The problem in the future is that if this isn't a JD track and drive axle setup, you don't know what kind of track to find to replace this one with if it ever goes.

Someone with more general snowmobile knowledge will hopefully be able to tell you what kind of track you have, and what kind of drive wheels and axle you have. I'd guess you count the window openings on the track, the number of drive teeth on the drive wheels, and measure the length and width as best you can, then post the question.

If you were starting from scratch, to put a new track on your trailfire you need a rubber track from a newer liquifire/sportfire, and three new drive wheels from the same machines. The new drive wheels and track are both still available aftermarket, probably by calling Royal Distributing.

Good luck.

And what happened to the cylinders and dash out of that old 440 your parting...? I'm interested.
Eric

[harleysportster]

Hello,
Please excuse my ignorance as I am a snowmobile mechanic neophite. I have a 79 trailfire 340 that was gifted to me years ago, it has been a great fun machine, and i have taken it everywhere. Last year the metal track bars (cleats?) started to come off, one split one side of the track quite badly. I found and bought a 79 440 with a good cowl and track to replace it. after taking the old track off and putting the 440 track on I realized it was too long! noticed that the 440 had holes drilled in the tunnel 1.5 inches back, so I drilled some new holes on the 340 and moved the suspension back. now the track fits fine, but I just realized that the drive wheels on the 440 have 10 teeth and the ones on the 340 have only 8, so now they don't line up... major frustration, will have to take it apart and change the driveshaft (stupid , I should have noticed when I had it apart the first time..) I cant believe they are so different, the drive shaft on the 340 is hex shaped and the 440 is round. I would like to put a rubber track on this machine, and I did look at the FAQ, but came away more confused. I believe most modern tracks are universal, is this true? I have an old indy with a good track, but it looks like the drive wheels are in the center, can I just move the drive wheels to align with the track? I just don't want to spend more time on this than necessary. Any advice would be appreciated.
cheers -Aaron

Arron,
Something doesn't sound right. If you bought a 440 Trailfire track, it should be the same length as the 340. See if the 440 track has a JD part number or a Kimpex part number. Are the cleats full width or just covering 2 belts, outside to inside alternating from side to side.
From your discription, the 340 track has only 8 drive lugs which would be a 2 inch pitch, the other track would be a 3.29.
If you want to use what you have, swap out the drive shaft as well.
If you want to install a rubber track(Sportfire or Liquifire) you will need to change out the suspsension as well from either a 82 and up Sportfire or a 80 and up Liquifire.
The suspensions had extra idler wheels added for support.

[manitobatrailfires]

"I believe the Trailfire is a 2.52 inch pitch."
Oops.

Sorry, the pitch is 2 inch as stated, I made a mistake.

I think the TF wheels should be 10-tooth, so perhaps your 340 wasn't factory anymore. The 440 seems correct. The round driveshaft confuses me, though.

[harleysportster]

There was a trailfire hex shaft.

[johnnycyclone]

Just for clarification. You do not need a Liquifire suspension to do a rubber track conversion, just the track and drivers. The Trailfire suspension will work fine, I know I have done this conversion on my 1980, and it works great.

I believe the 79 Trailfire had a round shaft for it's drivers, with the center wheel also. It looked just like the 76-77 Cyclone and Liquifire drivers. Later years went with the hex shaft. Could be wrong, but I have seen drivers like this listed on ebay as 79's.

Sounds to me like the 340 had the original JD set up, but the 440 had a non JD set up. Who knows where it may have come from, some owners can be very creative.

Terre

[Matt]

Terre, did you add any idlers to the suspension?

[johnnycyclone]

No added idlers Matt. Just put the complete Trailfire suspension back in, the way it was, which includes the idlers that bolt to the tunnel. No clearance issues, or any other issues. Ran all winter last year with no problems. Of course there may be some added benefits to using the Liquifire suspension, with the extra wheels, but it's not necessary for the swap. I also re-read Joe's track interchange info, in the FAQ section, and there is no mention of needing the suspension from a Liquifire to do the swap.

Terre

[Matt]

I'm just surprised - I would expect that you would see fast hyfax bar wear without them.

[AaronLishman]

Thanks everyone, I appreciate the good info! Looks like the 10 tooth wheel has 2 inch teeth spacing. Will try to replace the whole drive shaft once I get my van out of the unheated shop (shudder). Eric, I sent you a message about the 440 motor.
-Aaron

[johnnycyclone]

I agree Matt, I just don't know how much faster they are going to wear. In my case it probably doesn't matter, we don't get much snow here and when we do, it doesn't last long. This is just a beater sled I threw together out of spare parts, until I can get my rider finished, which is next summers project. I will keep track of the wear and see if it is significant.

Aaron - if you have the means to take some pics, and post them, that would be the most help. If we can see what you can see, there would be a lot less confusion. Just an idea.


Terre

[harleysportster]

Terre,
You are correct, the rubber track will fit as you have installed one into your Trailfire and kept the original suspension. time will only tell how long it lasts. I only suggested it since JD added the extra idler wheels and most brands out there with rubber tracks also use extra idler wheels. I think there was a change of location in the rear from the tunnel as found on the Trailfires to the rear swing arm as found on the Sportfire and Liquifre due to the torque of the track. I have seen tunnel holes cracked in a 78 CC sled with the tunnel idlers.

[johnnycyclone]

I agree with what you are saying harley, you have some good points. Nothing was ever done at Deere without good reason. The changes concerning the extra idlers, and the relocation of the top idlers to the suspension are correct. But 'm hoping this little 340 will be a little gentler on the track and tunnel, than the Liquifire. I guess time will tell, and if it should start to go wrong, I'll make sure to let everyone know. I'm not saying it should be done, only that it can be done. Now I just need more snow so we can ride.

[zr870]

I know this is an old post but I picked up a parts sled 80 trailfire 440 and the drive axle is a 12 tooth and has 3 cogs
Anyone know where this could be from