Polaris gurus' help

[Rowski]

I'm pretty p*ssed! I have a 1991 Polaris BigBoss 6X6 250 2-stroke with a blown engine.

What 4 stroke engine from Polaris would fit relatively easy into this vintage 6X6? It would be from a salvage or part ATV.

Should I just stick with the 250 2-stroke and rebuilt it?

Are there any other types of conversion?

Advise, comments???

What happened to my engine is mice chewed through my oil injector line, from the pump to the intake. The engine did not seize but the piston skirt broke. I just had the engine completely rebuilt (lower bearings, crank, connecting rod, piston, etc.) 2 years ago. I did not do the rebuild I payed to have it done, ouch!! So... I have yet to take the head and jug off to see the damage. Its possible I might only need a jug and piston. Its also possible that more is wrong.

This is my wood hauler. I'm using it on my friends 150 mountain side acres. Of course it broke right in the middle of the project. He is letting me use his atv, but there is nothing like hauling with a 6X6.


Thanks for you help!

Derek

 

[quads]

Sorry about your trouble Derek! That's too bad. I've owned Polaris for many years, but can't help you with your 4-stroke question. I can tell you that a lot of them had 250 2-strokes, so it should be easy to find an exact replacement if you decide to put another 2-stroke in it. Good luck!

 

[Rowski]

Right now I would just like to get it running for least amount $$$ possible. I won't have time to work on it till late August. So it will give me some time to find some solution. I've herd the 250 was very popular but had some trouble with the upper ends, piston skirts breaking?? So maybe I'll find a good used engine. That might be the most cost effective solution.

Thanks!

Derek

 

[Chrisg]

I would check Al's snowmobile parts I believe they sell salvage atv parts as well. I have bought parts there for sleds yrs ago skis,tracks, couls(sp) and such and they were real reasonable compared to new or other parts places. As popular as that engine was they probably have one right there and might do a trade with your blown one as a core towards the replacement. I know they were always willing to dicker when we went up there don't know how they are now though. Chris

 

[WoodMann]

If worst comes to worst you can always hunt down a jug on ebay.............................

 

[Skier76]

I'm thinking if it ran lean...it probably burned the piston pretty good. The jug may be salvageable..it may not. I think you'll be able to get away with a new top end and a new jug provided there's no damage to the crank or connecting rod. IMHO of course.

 

[Frostbit]

I would not contemplate trying to shoe-horn a 4-stroke in the chassis. You'll find it will require a lot of parts besides the engine, and I seriously doubt it will would fit, anyway. Consider the exhaust system would have to be changed, the carburetor and intake system, you'll need an oil tank, a radiator and the associated mounts, most of which are welded to the frame, which means they are not available as a part, so you would have to fabricate them. Getting the drive system to mate with what you have now spells nightmare...like I said, a tough and expensive job.

I have a 2005 6x6.

The 2-stroke is easy to work on. If it does in fact have a broken piston skirt, that chunk of piston is in your crankcase. If it dropped and lodged while the motor was running hard, I assume the engine locked up. This is not a good sign, as it may have attempted to be pushed through the lower case half. There is not room for it to pass under the crank webs and case. I have has two snowmobile engines drop skirts, both I repaired. Yours certainly could be done, but it may cost some $$$ if you can't do it yourself (I am a mechanic by trade, so the labor was free).

I would pull the motor out, as the cases need to be split to assess any damage to the crank and the crankcase halves. All of the piston chowder needs to be flushed, and it is not possible to get it all without taking the crank out. Too, small aluminum piston pieces will be in your crank bearings, and you would be best advised to also change your crankshaft end seals. If the case is cracked, its weldable. The crank can be rebuilt. Everything else is easy. Certainly your cheapest route to go.

Right on about the 6-by and its use as a wood hauler. I bought mine exclusively for this chore. I have 4 other atvs for what they do, none of which excel at wood hauling as the Polaris does.

Good luck getting her back to doing what she does best.