80's Liquifire Airbox Question

[Horicon Joe]

Remember ... Deere started with shorter boots.

The length and design (wall thickness) is the key to stopping the foaming. If possible keep your original boots. I have the prints for the original boots and it could be possible to remanufacture them.

discus- "I wonder if there is any foaming from the fuel sloshing around when you're bouncing down the trail or across the lake?"
To be clear, this is not the same thing at all. The foaming from Harmonic resonance is not from "sloshing" and it occurs immediately on the dynamometer that is not bouncing around. I don't believe venting can solve this problem because the fuel is immediately consumed as it foams. Stan told me Dick Bahr worked for Polaris before he came to Deere and solved their foaming problems as well.

discus- "I'm not sure how aware JD was back when they designed their snowmobile air boxes, but manufacturers eventually learned how to design them to work with the engine." Talking to Lee Hardesty (engine design lead) about the air box on the Liquifire, told me it was critical to run the air box and not individual pods. They did extensive work on them and it was not taken lightly. The big reason for them, was the air under the hood was so turbulent that they needed the air box to normalize and controll an even air flow to both carbs.

Most of us are occasional riders of these machines and likely can get away with cheating on the boots and never see a problem. However, if you do have a problem ....... you might be guessing as to what really caused it?
When Deere did the testing it was for the long haul and likely everything they did was for a good reason. When I rebuild my machines I do everything by the book if possible.

The reason I posted this was simply to allow all of you to make your own informed decisions.

My personal solution to this problem is a little different. I have it on my Liquifires so that I can remove the seat and pull the tank back in a couple of minutes. Tank clamps are easily removed with nuts and threaded studs and I have an extra 8 inches of fuel line to allow tank to pull back. It makes everything easy with just a little work. This also saves the boots from extreme bending that can cause cracking.

Good luck to all!
Cheers
Joe

[AirborneX4Special]

I must agree with Joe's analysis. Stick with the original setup if possible, especially the airbox. Deere was after the most benign air for the intake, which includes the u - shaped hose tucked under the box, rubbing on the jackshaft and supporting the fuel line. Not the easiest situation to service but keep mind the overall concept of a machine with the lowest center of gravity possible and a compact, lightweight chassis.

I was also going to trumpet Joe's fuel tank adaptation to gain access to the carbs but it seemed prudent to let him handle that. It's a simple fix that Deere could have implemented and appropriate that someone close to the source was able to envision and install.

[JDGuy]

THANKS Joe for the JD development information. My 80LF has 3 vintage challenges on it with new Mikuni short flanges plus other less demanding vintage rides without a problem.... so far. Lucky? I changed out the original long carb flanges to new Mikuni short flanges having no knowledge other than I wanted new rubber.