1970 Arctic Cat Panther 440J    

I replaced the stock HD27A carburetor with an HD62A. This carb has both high and low speed needles on the right side, away from the driven clutch. I also installed a choke cable and a primer.

The Color Chrome on the polished steel parts (shocks, body braces) had deteriorated pretty badly. Rust formed beneath the surface, which looked bad, plus it was starting to blister the coating. This product had been discontinued, but is now available again in limited supply. I removed the old coating from the above parts and repolished them. I reshot them with the Color Chrome, taking care to thoroughly dry the parts with a heat gun. This was about the only advise POR could give me to prevent a repeat of the rusting problem. I also shot the windshield strip, headlight and taillight rings to add a little more of the gold accents to the sled.

Removed the stock Salsbury 910 clutch and put on a Comet 94-C Duster in it's place. Used the stock spring and six solid pucks. This mild mannered trail putter is now a fire breathing dragon. Engine RPMs are way up and the JLO sounds very nasty (in a good way) at those speeds. Top speed is certainly up. I did my first trial run at night, and with the wimpy headlight decided it would not be prudent to test top speed.

It does run up to 40 in a big hurry however. This thing now accelerates HARD, and no doubt could pull a much taller gear with this setup. I may decide to detune some with more pucks in the Duster, or re-tune the Salsbury with heavier springs or lighter arms in the interest of keeping it a relatively sedate trail cruiser, while keeping some of the new found power.

After all of the troubles I've had getting this Cat to run right, I'm getting a big kick out of it now!!

As the riding season began, the engine would only run on the PTO side cylinder. I eventually traced the problem down to the mag side crank seal being shredded. I just wish I knew how that happened.

With the seal replaced, the engine still ran poorly mid-range, idled fine and ran pretty well wide open. After doing a lot of carb tuning and experimentation, I decided I would try removing the "carburetor intake elbow" that fits between the carburetor and intake manifold. It turns the carb 90 degrees and moves it out away from the driven clutch.

This change improved things greatly. I took the sled on a twenty mile ride and it performed flawlessly throughout, from low speed tight trail riding to wide open across fields. Power is still lacking, but I believe much of that is clutch tuning. I know from experience that putting a well tuned 94C Duster clutch on my 71 Panther is good for an additional 10-15 MPH top end speed.

I pulled out the JLO and completely tore it down. I didn't see anything drastically wrong. The pistons were scored some, but I don't think it was enough to cause the poor running. I installed new crank seals, NOS Wiseco pistons, NOS Bosch points (thanks Dan), new coils, plug wires and caps. I'm still amazed when these things start after I rebuild them.

Expanding on the custom theme of this sled, I polished much of the aluminum on the engine. The fan housing and cylinder covers were polished and I replaced many of the fasteners with polished stainless. I painted the starter and the intake manifold, and added a nicely polished G.E.M. velocity stack. I was not happy with the silver exhaust system, so re-painted it satin black.

The Platteville Cat spent the season in the shed. I ran it maybe two miles early in the season, but it was clear the clutch overhaul did not improve performance one bit. I'll yank the JLO and do a complete overhaul this summer.

I've consolidated everything that was here into the main page for this sled, and will start fresh here beginning this riding season.