Cross Country

[guitardude081]

I'm planning on running the vintage class in the USCC circuit next winter, and my search for a sled is going to be starting soon. I'm going to run a 440 Liquifire. There isn't much competition, so it really doesn't have to be a lightning bolt. Which Liquifire would take the beating more; a '78 w/ rubber track, or a kawi? Speed isn't the issue here, it's which one will do a 50-60 mile torture test every saturday. The thing that appeals to me the most about the 70's ones is that you can bore the jugs if you have an oops moment and burn it down. I do like the ride and handling of the Kawi Liquifires better, but I can ride a '78 just as hard as a Kawi. I'm only 23 so, even after a hard ride on Saturday, I'll feel like a million bucks by noon on Sunday. Let me know what you guys think.

[JDXspec]

I would say use a 76 LF (more plentiful) and put a rubber Track under it. Its been done before. I like the Kioritz engine better for dependability. Premix so your know you have lubrication. With the standard 34s vs the PJ 36s they are less finicky when it comes to temp changes.

[wadeo108]

if your going to run one from the 70's you might as well forget about a rubber track. if you can find a cc track you will pay top dollar for it. if you do find a rubber track i would use the suspension out of the 80's for a better ride (it was based of the cc suspension so it will take it). double nut everything, and talk to the old time racers on what else to do to keep everything together (the old man has a good story on that and i have the pics to go along with it).
the choice is up to you and you will get differant opions form everyone. i would run a 80's liquifire, i grew up with one and beat the piss out of it all the time and never had a problem. you will have to remember that either way you will be racing a sled that is 20 to 30 years old, you will should tear everything down and go through it to make sure you will be good to go.

[Bassps70]

I would go for an 80's liquifire. I had my 80 with invader heads up in michigan a few weeks ago, and ran 350+ miles in 3 days. Aside from blowing out a bearing in the rear skid (my fault for not replacing it) it preformed flawlessly. If you get one, plan on replacing all the bearings you can find. As I learned, it's not worth risking it for a $5 bearing. Also, stay away from parts unlimited shocks. I sheared the top mount off of 2 of them in under 100 miles. I have 700 miles on a front shock from an arctic cat bearcat, and its still going strong. Good Luck.

Mark

[guitardude081]

I put over 500 miles on my 1980 Liquifire after I restored it, and the only real problem I had was that it was finicky about temp changes. Of course I'll go through everything. I plan on doing a mechanical restoration. It'll see a re-ring every season as well as clutch rebuilds. I plan to run both 600 ameteur and vintage. The Liquifire will see as much maintenance as the 600 will. I'll have to look to the former CC racers for reinforcment ideas. Burn downs are my primary worry because river and lake running require a lot of long term running at high rpms. Dennis Top from Baudette, MN runs a 1980 LF in vintage and most of the guys I talk to say he does pretty well. They say that sometimes he's the only one that races. I'd like to see some big turn outs so it turns into a big competition like the other classes. Bull sessions are more fun when there's a little rubbing going on in the corners. As a snowmobiler, vintage is my primary focus so I am more concerned about having a good Liquifire vs. a good 600 stocker. Either way, it's gonna be a blast. It's the first time I've ever looked forward to getting battle scars on my Deere.



~Jack

[400brian]

I've been considering putting a dual exhaust gas temp gauge ( EGT ) on my 340S.

The UL flyers run them. They won't alert you to a temp spike, but you will have a more or less real time idea of what is going on in there.

It should warn you of a deteriorating seal, or a restricted jet ( once you have established a normal baseline temp ).

Running WOT for extended periods is a good test of your tuning abilities!

[The S Man]

The EGTs' have to be about 8 inches away from the center of the combustion chamber to be accuate. I have used these on my drag sled but for refurance only. I have been told by many that by the time you see it on the gauges it is already too late.
Still the best thing is to make a pass and look at the plugs, also look down the plug hole, you should have a little wetness around the outside of the piston..
Just my 2 cens worth, take it or leave it, I am by no means a pro at this. Like anything else, test and test again. Between that and clutching that should keep you full time busy


:blink:

[JoeRainville]

Jack,

I think the 80 LF is a good choice, as Deere built almost 9,000 of them. They handle well, aren't very heavy and have some suspension. Not to mention a very rugged track. If you can swing it, get the jugs nic'ed and use new Wisco pistons and the rings made for iron or nic'ed jugs. That should help with the motor durability somewhat.

My favorite pick for a vintage race would have to be a 78 LF, but I would never have the heart to do it. It was a great fun to race my 78 CC in the up hill drag race last weekend, but I would never want to 'clank and bang' with it.

Good Luck, and take Rich's advice.

-Rainville


B)

[That Girl Racing]

Funny you guys are talking EGT's. We have ran them for years but this season I have put O2 sensors on the race sleds. I will run both systems till I get the O2's figured out but I think the EGT's are kicking gravel down the road. Peter

[400brian]

The EGTs' have to be about 8 inches away from the center of the combustion chamber to be accuate.

From what I have learned from the UL guys, ( and they are running piston port Rotaxes for the most part ) Rotax did some testing and found that the temp probe must be around 4" from the piston to learn anything useful.



Here is a post from one of the Graybeards in the UL hobby:

[ I would suggest about 4 inches from the skirt. This will get it out of
the casting and in the manifold.

Cuyuna never spent the time on a dyno/test stand to come up with a
proper location. The 4 inches is recommeneded from the Rotax folks who
did take the time to get it right.

I have a 503 on my test stand for a customer and noticed the muffler
has a EGT hole out in the tapered potion about 3 inches from the
second ball joint. So any people stuck the hole for the probe in the
wrong locations and then screwed the engine up chasing the jetting
using incorrect EGT readings that they now weld threaded bosses on the
exhaust manifold.

Also, check the depth of the probe and space the probe such that the
end is centered in the pipe. This may mean adding several AN 3 washers
on the probe before sticking it in the hole you made for it. ]






That means a probe quite close to the flange of each side of the exhaust manifold.

As I said, often a quick spike will go un-noticed or the damage will occur before the gauge registers and the operator can react. But the EGT can be used as a tuning aid. We can debate the usefullness of the EGT gauge, but I've noticed that the guys who run 2 strokes hard tend to use them.

Peter, where do you locate your probes? How is the O2 sensor superior to the EGT?

[Danzig]

I am curious also about the O2 sensor working, I do know that these sensors fluctuate on a scale using a Genesis scanner which I am very fond about, but measuring exhaust gas temp has me baffled on this one..

[That Girl Racing]

We run our probes 4" from the piston face but there is no "right" location. Typically the further down the head pipe the hotter the temps. EGT's are only measuring heat in the pipe not air/fuel mixture. They change with timing, engine load etc. They also rise as you go down the track. O2 sensors tell the f/a mixture in real time. They are not changed by load, timing etc. EGT's were the latest and greatest, but O2 technology is the beginning of programmable fuel injection on race sleds. Peter

[ICCSF 108]

Peter, does the 02 sensor hooked to some sort of memory sensor that stores the info & can be down loaded later?? now that would be great..
All these things are great for tuning purposes BUT once CC racing you don't have time to look at, If you do or are your not going fast enough.....


Kenny

[That Girl Racing]

Kenny. I don't expect a driver to look at any gauges going down the track. We monitor, pipe pressure, jackshaft speed, rpm, water temps,EGT and O2. Even engagement speed is set by the MSD ignition. There is no real need for the gauge to be on the sled. All info is downloaded after a pass and reviewed on a computer. Digatron, RacePak and Aim all make data aquisition systems racing. Peter

[ICCSF 108]

Peter, I wasn't directing that last statement toward you by no means. I was just tossing it out there as a general statement....
But Tell me about pipe pressure, I had never heard that before, what do you learn from it & how can it be changed??? By the MSD ign.???

Kenny