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Discussion Starter #1
OK, so a little background.

I have an offroad buggy that I have been working on. it has Honda 400 EX long travel front suspension, Arctic cat 550 rear suspension and is a single seat full tube chassis.

Currently it is powered by a ragged out 10 hp Briggs with a Comet CVT and an 8:1 reduction gear box.

the motor is toast, so I just picked up a Polaris 250 2-stroke motor that I want to fit in this chassis.

I was able to get he motor (ec25pf-01) with all the controls and wiring from the handle bars down with the head light for less than 100 bucks. The only thing I am missing is the ignition coil,the air box, and the driven clutch/cover)

I have a couple questions.

1 - I know its air cooled, but does the clutch cover provide the cooling air flow? Right now I plan to either add scoops on the sides of the car to force air over the cylinder or add a fan.

2 - The motor number on the engine plate says 87-03033 which I assume means its an 87 motor?

3 - I can find performance parts for 88 and up , but nothing for 85-87. Will the parts interchange?

4 - I notice that aftermarket exhaust for a trailblazer wraps around the head and does not go right out the back, are trailblazer and trail boss exhaust interchangeable ( considering I have no constraints on mounting, just overall length)

5 - I dont plan to run a clutch cover, Does the intake pick up from it? and can I simply put a small cone filter on the carb inlet and delete the rest?

The motor seems to have good compression and turn nicely. I plan to clean it all up, and get it running in its current state in the car, and then once I have it all set up, pull it back out and do some power upgrades and a full rebuild. What would you guys suggest. I have seen big bore kits for it along with different CPIs and power pipes, but like I said most of them state 88 and newer. Will they work on an 87 motor?

I am new to this, so thanks for any input in advance

Justin
 

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Welcome to the board!:med:
 

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Discussion Starter #3
so I tore into this motor over the weekend

I found some oil/gas residue inside the flywheel housing, I assume this is not normal? bad crank seal?

Any suggestions on how to test the stator?, its pretty dirty from the residue, but It looks pretty solid

Second, It is hard to tell, but I think I feel a tad bit of end play in the crank on the PTO side. how much is too much?

3rd, any suggestions for good aftermarket crank seals and main bearings? I could order polaris parts, but I did know if there are any reputable aftermarket brands.

I think at this point I am going to tear it all the way down and send some parts out to ritter racing ( cylinder bored and ported) and a trail lightened flywheel

thanks for any input

Justin
 

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Oil residue on the stator is definitely a bad crank seal. You can ohm test the stator with the proper specs in hand. I don't have a manual for anything that old or I'd post them up for you. You really shouldn't be able to feel any end play. As far as pipes go you will be fine with whichever of them fits better. If you run a pod filter on the carb you will have to test and tune to get the jetting right as it will start out very lean. No need for a fan to cool it. Definitely come up with some sort of a clutch cover. 9lbs of aluminum spinning at 8000rpm coming apart WILL cause you some major harm or kill you.
 

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Discussion Starter #5
Oil residue on the stator is definitely a bad crank seal. You can ohm test the stator with the proper specs in hand. I don't have a manual for anything that old or I'd post them up for you. You really shouldn't be able to feel any end play. As far as pipes go you will be fine with whichever of them fits better. If you run a pod filter on the carb you will have to test and tune to get the jetting right as it will start out very lean. No need for a fan to cool it. Definitely come up with some sort of a clutch cover. 9lbs of aluminum spinning at 8000rpm coming apart WILL cause you some major harm or kill you.


Thanks for the input. I do plan to run a steel clutch gaurd for safety, but it wont be a sealed cover like the OEM one. The engine is rear mounted and there is a sheet metal firewall between the driver and any moving components. My worry was the intake system that is built into the OEM clutch cover. I wont have any of that.

I will go ahead and just rebuild this thing I think. Any input on a decetn aftermarket brand for crank bearings?

Thanks

Justin
 
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