Best Motor swap for PS 580

Team Wild · Jan 21, 2010

Ok I have a 95 PS EXT 580 carbed. I have tweeked on the chasis and now I was thinking the next thing would be the engine. What would be an easy swap that would give this old sled some more get up and go. I was planning on keeping it carbed for ease of the swap. I would like to go 700 or bigger.

Idcatman3 · Jan 21, 2010

About the only bigger motor that would go in there easy would be an older ('88ish-97ish or '99-'00) 700. I'm sure you could get/make a motor plate to fit just about anything though. We used to have a 900 triple in one of those chassis, but I'm not sure how it was done.

Idcatman1 · Jan 21, 2010

Idcatman3 was pretty young when I had the T Cat engine in one of those. It took a little cutting and welding and some brackets from a T Cat. The EXT doesn't use a motor plate. It would take some cutting and welding also to get a 700 ZR or Wildcat engine in it. Your 580 is almost as fast as the 700 would be anyway and more reliable in my opinion. If you are intent on it though and handy with a welder you can get just about any engine in any chassis if there is room.

sprockethead · Jan 24, 2010

Y not do a big bore on the 580? I think u can punch them out to 670. U have to use cylinders from a ZR580 though, they r triple port. The PS cyliinders will catch the rings and break. I cant remember what pistons u used to do this, but someone on here should know. Seems like the esay way to make some more ponies for this sled.

Sprocket

sprockethead · Jan 24, 2010

U use stock ZR700 pistons but u have to shave the shirts to match.

Sprocket

Idcatman1 · Jan 24, 2010

I am not sure but I think you also have to stack base gaskets or get a shim to raise the cylinder. I think the 700 piston is taller than the 580. Todd Porter at Rocky Mountain Performance in Rigby Idaho 208 745 9040 used to do some the 580 big bores and might be able to help.

sprockethead · Jan 24, 2010

I see shave the skirts to clear the case and stack the gaskets to keep piston crown from head.

Sprocket

Idcatman1 · Jan 25, 2010

I think the distance from the pin to the top of the piston is higher on the 700 piston than the 580. I can't find a 700 piston in my pile of stuff to compare though to make sure. Shaving the skirt wouldn't fix that. M1000 pistons in an 800 or 900 requires a shim for the same reason.

Team Wild · Jan 25, 2010

Very interesting stuff guys. I will look into this further. The 670 idea sounds like a fun project. Thanks for the info.

clutch · Jan 25, 2010

I have a 94 EXT mountain cat that my son still rides sometimes. I put a PSI 625 big bore in it way back in 97. It uses the 650 wildcat piston. Cutler used to do the 670 and it used the 700 piston. The skirt has to be shortened, the pin boss opened up wider and PSI made a thick plastic base gasket for there kit. I had a lot of fun on that sled back in the day. It would give any stock 700 more than it could handle. I ran the twin pipes on it and it was reliable as could be. To date it has almost 11,000 miles on it now and still going strong. I big bored it at 3500 miles.

fordpickupman · Feb 18, 2010

T-cat it..

I knew a guy that owned the CAT shop in Cottonwood, he had a 900 T-cat in one. If I remember right, he had swapped the PS hood and pan for a ZRT/PE hood pan for pipe clearance. It was named "Clyde". Piped and dialed in with a 156"x2" "BigHorn" track(who has been around long enough to remember the "bighorn"?). He was the big dog for a few years, until a bunch of the guys made the jump to the factory built T-cat mtn cats. I remember being in awe of that sled, in my mind at the time I thought one would have to be half crazy and a Mountain of a Man to ride it to its capacity. This was around 1996.

SouthDakotaM8 · Feb 19, 2010

Did anyone figure out where to get the Big Bore stuff to put in a 580? Anyone know what it all takes?

firecat99 · Aug 30, 2010

I have a ZRT 800 big bore pipes and everything, mean sled will let motor go for the right price

580mod · Jan 12, 2024

clutch said:
I have a 94 EXT mountain cat that my son still rides sometimes. I put a PSI 625 big bore in it way back in 97. It uses the 650 wildcat piston. Cutler used to do the 670 and it used the 700 piston. The skirt has to be shortened, the pin boss opened up wider and PSI made a thick plastic base gasket for there kit. I had a lot of fun on that sled back in the day. It would give any stock 700 more than it could handle. I ran the twin pipes on it and it was reliable as could be. To date it has almost 11,000 miles on it now and still going strong. I big bored it at 3500 miles.

Clutch, old thread, but I am looking to do this to my 580, I have a set of black magic pipes, and access to 40mm or 44 mm carbs, I am wondering I plan to get this motor sleeved, will there be enough thickness left in the sleeve for a 700 piston? Setting the 700 pistons on top of the 580 jugs looks pretty thin when centered

clutch · Jan 23, 2024

Not sure on the sleeve with the 700 piston. The 625 I did was bored to the 650 piston size and re nicasealed.
Part of the reason I went with the 625 was of concern about the thickness of the bore. I know Cutler did the 670 kit, not sure if it was sleeved or plated though.

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Best Motor swap for PS 580

Team Wild

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