I have heard that the sp700 engine came from a snowmobile. Which, I heard was a 800 F.I. My question is, is this true? I was looking on the Polaris web site and couldn't find a four stroke snowmobile anywhere. Does anyone have any in depth knowledge of this motor?

 

Its in the sept issue of Snowtech along with the arctic cat four stroke.

No real good info just a short rundown on them and a few pics.

The Polaris frontier (780cc)has 48hp with closed loop EFI. Its a limited build this year with full production scheduled for the 2002-2003 season. It looks very simaler to the atv engine and I will guess the extra 100cc comes from a longer stroke vs a bigger bore. Then again it could be both???

The artic cat is a 660cc three-cylinder with about 45hp. I read in another mag its based on a car engine and it looks huge.

 

The motor in the snowmobile is the same as the on in the 700, the original motor is an 800, the 800 is sleeved to a 683 I believe is the correct displacement.

 

I believe you are correct polarisman!

 

Polarisman
The sportsman is sold as a 700 yet is only a 683. What little info I have seen on the frontier lists a 780cc engine. It may say 800 on the hood, kinda like how it says 700 on the sportsman. [img]i/expressions/face-icon-small-wink.gif[/img]

The Sportsman 400(425) and 500(499) are both of the same engine design. The bore/stroke of the 400 is 87.9mm/70mm. The 500 is 92mm/75mm. Can you turn a 400 into a 500 by swaping some parts? Maybe but I doubt it. Will you be able to turn a SP700 into a 800? Maybe but again I doubt it.

 

Shaggy,
There was a guy on here that put a jug and piston from a 500 on his 425 Xpedition. I haven't heard from him in a while, but it seemed to be holding up well. I would doubt if Polaris redesigned more of the 780 then they thought they had to to get the displacement down. Polaris has put themselves in a good position to increase displacement, fuel delivery, camming from this motor all without having to redesign anything. I see a 800 Sportsman EFI in the future.

Brian

 

dusty

Just changing the top end to the 500 bore changes the 425 into a 465(?). I am curious as to why this was done. A different jug and piston can't be cheap. I can't find anything on this using the search feature. Any hints on a user name or post title?

elroy

What is the cost of a new crank, piston and cylinder for the 500???
If a 700 can be made into a 800 it would need a crank(assuming its different), two pistons and two cylinders.

 

Shaggy,
You are correct. I believe it doe's work out to 465cc, and no, it wasn't cheap. My point was that it is quite possible for Polaris to increase displacment with parts they have already manufactured. The 425 is a good example because all parts, with the exception of the crank on the Xpedition are interchangable with the 500. It is just a guess that the 700 has the same familiarity with the 780 sled motor.
The guy that did this on his 425 was 425Xpedition. He is a Texas mudrunner, and I suppose he did it to run those huge tires those folks like so much.
Brian

 

The reason for putting the 500 cylinder on the 425 was to increase the bottom end power. You are correct on the displacement of 465cc. The increase in displacement does help some but the biggest increase in power comes from the increase in compression. If the HPD piston is used the compression increases from 9.2 to 11.5. If a stock 500 piston is used the compression will increase to 10.2. Most of the power increase comes from the compression increase. It is a simple bolt on job. It is not real cheap to do. The parts run close to $600.

 

SHAGGY500HO,
The part numbers and MSRP are as follows:

2000 Sportsman 500
Crank..........3085399.....$549.75
OEM Piston.....3085866.....$69.75
OEM Rings......3085379.....$26.75
Cylinder.......3086811.....$269.75

2001 Sportsman 500 HO
Crank..........3085861.....$439.75
OEM Piston.....3085866.....$69.75
OEM Rings......3085379.....$26.75
Cylinder.......3086811.....$269.75

And all parts are currently available and in stock at Polaris.