'78 Liquifire 1st sled need advice

[farmboy76]

I bought a '78 Liquifire from a relative (original owner) for $100 a couple of weeks ago.
Cleaned the carbs and gas tank out, put new fuel lines on it, and away we went!
The sled sat for almost 30 years, but was prepped for storage back in the 80's, so I lucked out there.
This is my first snowmobile ever. I'm used to working on motorcycles and honda atc's, but these are a completely different animal.
I need some advice...
Riding with my dad, it topped out at about 45mph. I looked, and the secondary isn't opening up all the way.
Do I need a special tool to remove the secondary? I know the primary takes a special puller.
Next, the gauges The water temp gauge doesn't work. Is there a place to get a new sending unit?
Also, is it possible for the speedo to not work, while the odometer still works?
Finally, the track. Mine is in good shape for now. Is there a newer track out there that is a direct swap-in?
I have fond memories of this thing at the sledding hill when I was a kid, and I want my little boy to have memories like that.
I'm looking forward to being able to restore this machine in the next couple of years.
Thanks for the help!

[69camaro]

78 Liquifires are my personal favorite. I'm going to beat everyone to the punch on this one. Replace the crank seals.

Duane

[Matt]

No special tool needed for the secondary, just remove the retainer bolt and slide it off. Make sure it has the 3 wear pucks and everything moves freely.

You can't replace just a sending unit on these gauge sets. There is some info in the FAQ about using a generic aftermarket temp gauge, or I have reproduction gauges in my store that match the originals, but they aren't cheap.

Seems unlikely that the odo works but not the speedo, but I'm sure it's possible if something failed inside the gauge.

No easy direct swap-in for the track on this one. Do a search here and you will fine some topics about track conversions.

[ICCSF 108]

First off welcome,
just for curiosity what size is it, 340 or 440, Does it have a cleated track or all rubber?
The Water Temp Gauge is a mechanical meaning no sending unit that can be replaced. you can either purchase a water temp mechanical gauge with shortest lead available from after market or there is a guy selling repopped OEM style gauges with short snowmobile leads, I don't know who he is but someone on here will or maybe Matt is selling them in the New Breed parts store here? either way I would not go Cheap on this part as IF it fails so could possibly your engine...
The driven clutch is just held on by one bolt in the middle, there is also a key in the shaft, sometimes if the shaft gets rusty the driven comes off really hard, so don't ruin it getting it off..
check the three cam buttons for excessive ware..
you 45MPH problem could be as simple as a worn belt or the driven sticking or problem with the drive clutch, or in your carbs, make sure that you are getting WOT by with the air box off & holding the throttle WO stick a finger inside the carb & make sure that the slide is rising all the way to the top.. do both sides like this also ck to make sure that at WOT both slides on both carbs are at the same height.
Also make sure when you JUST touch the throttle make sure that both slides rise at the exact same time.
Also Make sure the exhaust isn't plugged ( mice & other rodents like to make nests in them which can prevent a 2 stroke from winding out)..
What kind of RPM are you getting when you go from idle to WOT ( within 25-50 ft. you should be seeing around 7000-7500 on your tach )

Grumpy

[lwb140]

farmboy , sounds like you have a great project ahead of you , 78s are great sleds youve gotten some great sdvise so far ,im about an hour west of indy give me a shout if you need anything else wade

[WinnipegStPaul9]

Welcome Farmboy! Like Wade, we're Hoosiers too. We're in Churubusco near Fort Wayne. Usually have some parts laying around and am always willing to help with restoration. Before you suffer a major catastrophe you need to consider replacing the crank seals. Regardless of how the sled was stored, those seals are old, old, old and most likely have hardened. Don't take a chance of burning down a piston because of a crank seal. Call me at 260-six-0-nine-two eight three three if you have questions. Again welcome aboard!!

DA

[farmboy76]

Sorry, I missed it in my original post. It's a 440 with the cleated track.
I read up a lot on here and plan to replace the crank seals probably this summer when I go through it. There's not much chance to us getting much more snow this winter, and we have a planter to overhaul for spring.
Matt, thanks for the info on the gauge.
My tach is not currently working. It shows 1,000rpm when running. But from my research, I need to check and clean some wire terminals.
I think the secondary is sticking, judging by the marks on the pulley. The belt is almost new. Is there a recommended lube for the secondary, or should I leave it dry?
I blew the exhaust out when I got it. It was stored in a hay barn, and it looks like the mice chose the hay over the sled. Thank goodness.
Thanks for all the info, it's a big help!

[69camaro]

If you want to change the track to a all rubber track 85-88 Arctic Cat Eltigre tracks work along with Panteras, Panthers, and Cougars.

[harleysportster]

Yes, the AC tracks fit but not a perfect fit without minor changes.

[WinnipegStPaul9]

In my humble opinion you're just as well off keeping the JD Track. Yes I have the AC track on my CC but it was not without a lot of work.
DA

[farmboy76]

I don't want to replace the track unless absolutely necessary. I just want to be prepared in the future.
I'm planning on keeping it for a long time.
I may have a chance at an '80 sportfire, and an old JD snowmobile trailer. I'm working on the guy.
It would be fun to have a pair with trailer!

[lwb140]

I don't want to replace the track unless absolutely necessary. I just want to be prepared in the future.
I'm planning on keeping it for a long time.
I may have a chance at an '80 sportfire, and an old JD snowmobile trailer. I'm working on the guy.
It would be fun to have a pair with trailer!

ive got a 78 with the cat conversion , if you are just plunking around the corn field you will never see an advantage of the cat conversion unless maybe on ice , that same track on your sled was used from the 74 jdx sleds through the 78s , in other words there are many,many usable tracks around to burn up before we are out of them , on the flip side it s a big job to change them , not something you want to do often ,this summer after you get that planter put away, inspect your track closely , i bet it has a ton of miles left in it.

[harleysportster]

You can stud the 2/3 track with either the JD star studs or short straight studs and have good results.

[farmboy76]

I got the new parts for the secondary yesterday (thanks Matt) and got it all slapped together this morning. We got about 1.5 inches of snow this morning, just enough to test the new speedo in the bean field. I must have done something right, because I hit 65mph in the flat on frozen ground and a little snow. I could hear the belt spooling out like I hear on my dad's Exciter, so I think changing the pucks made a big difference.
Thanks for all the help, guys!

[Sprailfire340]

Congrats