Sportfire and Trailfire clutches

[Ryker Carruthers]

Ill let you know how it goes for me.

[JD600]

My guess is that it will make it engage at a lower RPM and make it a little more sluggish off the line since the Sportfire had something like 10HP more than the Trailfire had. If i had the Aaen Book with me at work, i'd be able to tell for sure, but i can't remember the difference in the weights off the top of my head.

DE

[JoeRainville]

Montee, Dustin is close...

The Sportfire was rated at 42 hp in 1984, so I will assume it was about that from 80-84. Deere stated it had 15% more power than a Trailfire 440, so that makes the TF "about" 38 hp or so. The 4 hp difference isn't a big deal, so the sled will probably engage about the same RPM, as I think they both used silver springs. But assuming the Sport rev's higher, the weight could actually be lighter, and let the Trail rev higher.

For example, if you bolt a Trailfire clutch on a Liquifire, it chokes the sled down to about 60 mph and 6500 rpm as the Trailfire wieght is heavier than a Liquifire B-1, to keep the RPM's down.

If the weight is heavier, the sled will go slower than stock, generally speaking. If you do run the Sport set up (It also has a multi-angel helix in the driven) you may have to re-jet the carb, as you are changing the load profile on the engine.

In short, try it, check the plugs for color and see what happens. You do run a risk of over-rev, but it may be slight. Difficult to predict from the keyboard!

-Joe

[JD600]

Thanks for straightening me out Joe. I thought there was a bigger HP difference between the T-1 and T-7 Fanners.

DE

[Ryker Carruthers]

Well, I have a minor setback, The threads in the crankshaft to mount the clutch need cleaned and we don't have any metric taps. Good news is the taper fits and the clutch looks great. Hopefully dad is ordering the tap today so I can get it cleaned tomorrow.

[Ryker Carruthers]

My guess is that it will make it engage at a lower RPM and make it a little more sluggish off the line since the Sportfire had something like 10HP more than the Trailfire had. If i had the Aaen Book with me at work, i'd be able to tell for sure, but i can't remember the difference in the weights off the top of my head.

DE

The manual says the trailfire weighs 375 pounds

The clutch that was on the trailfire I have was a TR-800 clutch, I know that was on the later liquifires at least. Did they ever put those on trailfires? I still have it but it has a chip out of the edge and is cracked on the other side. How would a trailfire perform with that style clutch?

[kenwaters]

Ryker,
The threads on the end of the crankshaft where the clutch mounts is 1/2 - 20 threads. they are NOT metric threads. Match the threads on the clutch bolt to the tap. The crank is hard, so take it easy with the tap using heavy oil or even grease as a lubricant. Please don't force the tap as your problems will grow.

I sent you a PM.

[Ryker Carruthers]

Ken, I wondered if it was 1/2-20, the die would start on the bolt but only half a turn or so. Maybe the bolts threads are screwed up. I will look at that tonight if I can get dad to take me to the shop. Thanks for the info! I will call you tomorrow sometime.
Thanks again,
Ryker Carruthers

They are talking about 5" of snow thursday, hope I can at least get it out. With the resleeved cylinders and new pistons I can barely turn it over by hand and it hasnt even seated in yet- I'm happy with that

[JoeRainville]

The clutch that was on the trailfire I have was a TR-800 clutch, I know that was on the later liquifires at least. Did they ever put those on trailfires? I still have it but it has a chip out of the edge and is cracked on the other side. How would a trailfire perform with that style clutch?

Ryker,

The TR-800 was only used stock on the 1982-84 Liquifires, but was offered as a "wide belt kit" for the80/81 Liquifires. That clutch is 8.0" in diameter, and is larger than the Comet 102-C. This gave the clutch set up a "overdrive" compared the regular 102-C's. To take advantage of that, Deere gave the 82-84 LF's a deeper gear ratio in the chain case, down to 21/39 from something like a 22/35 "I think".

If you could calibrate a TR-800 for 38 hp or even a 42 hp Sporty, and reducted the gear ratio in the chain case to take advange of it, you could have greater acceleration with the same or better top end.

However, calibration parts are pretty dried up for that clutch, and please, NEVER used a cracked or chipped clutch on a sled. It's just waiting to explode in your face. And that is a really, really bad day. Your cracked unit is really only good for parts.

I hope this helps,
-Joe

[Ryker Carruthers]

However, calibration parts are pretty dried up for that clutch, and please, NEVER used a cracked or chipped clutch on a sled. It's just waiting to explode in your face. And that is a really, really bad day. Your cracked unit is really only good for parts.

I hadnt planned on using it thats why I got the sporty clutch, I will probably keep it around though because i'm working on dad to get a liquifire

[JoeRainville]

Ryker,

I figured you probably knew not to use a cracked clutch, but just in case you are new to sleds I wanted to mention it.

I do have NOS (new old stock) clutch weights and pin kits for the Sportfires, along with a new helix for the driven clutch. But, I won't be in NY until the end of the month where most of my parts still are.

The clutch flyweight mass is what Dustin was taking about in his post, not the sled wieght. "Generally" the heavier the flyweight, the harder the launch but lower the max RPM of the motor. A stiffer spring generally gives you a higher engagement RPM, while a less stiff spring gives a softer, less agressive take off. Aaen's clutch tuning handbook would be a good read on the subject.

I hope this helps...

-Joe

[Ryker Carruthers]

Good to know thanks Joe! you could say I'm new to sleds as I'm only 15 but I know my way around engines and have worked on my dads sled for a few years.
Ryker Carruthers

[monte44]

The 102 on my 83 TF has U arms and a silver spring. I looked at the JD parts book for a TF and it calls for U arms and silver spring but other comet guides say purple spring and B arms. Which is right?? Thanks.

[Ryker Carruthers]

I had a chance to get the sled out on grass after a freezing rain, it suprised me and lifted the skis up coming out of the shop... It does alright taking off but I cant get above 30 mph.
What is the deal? If this helps at all it has new pistons from parts unlimited and resleeved cylinders... It isnt completely broken in yet, could that be the problem? Or xould it be needing different springs and weights in the clutch?
Thanks, Ryker Carruthers