Today I purchased a 2000 Polaris Scrambler 400 2 stroke. I didn't pay much for it, because it didn't run. I took the carburator off to clean it and saw a quarter sized hole in the left engine casing. After I took the head and cylinder off, I found that the entire piston skirt had busted off. These pieced got wedged between the rod end and the case, resulting in the pressure that busted the hole in the case. My question is, what are my options to fixing this? Does anyone have a bottom end that they want to sell me? I had my explorer 400 rebuilt last winter and it cost me 1300.00. Not looking to put that kind of money in this quad. Also, could I just get a left side case, and replace it with the right side? I believe you have to use the original case halfs, as they are cut from 1 piece and are only mates to themselves. Any advice will be aappreciated.

 

You can get a used left side case half from ebay.Many have done this to patch 400s up.Common problem when people let pistons go too long and skirts break tearing up cases. You might as well figure a new rod assy,crank bearings and seals and rebuild it right.If not,just part it out.

 

I was going to do a new case half, and a piston kit. Why wwould I need a new rod, crank, and all the parts? They all seem to be in really good condition.

 

IF there is no up and down play in the lower rod bearing plus crank bearings feel ok,possible to reuse them. Hard to really find one in perfect condition after piston skirts have broken. It's not just the immediate breakage that damages lower ends,but the continual wear and being exposed to bits and pieces of piston wear that work it's way into the lower rod bearing and crank bearings. Have had some customers that transferred crank assemblies to new cases and got by with it,some didn't and had to split the cases again. Just the thought of going to all that trouble of building an engine from the cases up would be enough for me to make sure.

 

So far I have not been able to find the right year case half for my Scrambler. I plan to take the case apart today and see how bad things are down there. At this point, I am considering having the case half welded. I have read that the chain driven 2 strokes were different than the shaft driven 2 strokes when it comes to the older 3 chain quads. What year would I be able to use with my 2 stroke that is shaft driven to the 4x4? I found a machinest that will bore my jug for 50.00, so that is happening next week. I need to find a case half asap, so I can get this quad out of the way. Like most people I have two many irons in the fire with one garage.

 

No difference in the cases from 1994-2003 when they ended production. All case part numbers superceded to part # 3086740. Usage : 3084774 (supercedes to 3086740)

Year Product Model Assembly
1999 ATV SPORT 400 CRANKCASE and CYLINDER - A99BA38CA
1999 ATV SCRAMBLER 400 CRANKCASE and CYLINDER - A99BG38CA
1999 ATV SCRAMBLER 400 CRANKCASE and CYLINDER - A99BG38CB
1999 ATV XPLORER 400 CRANKCASE and CYLINDER - A99CG38CA
1998 ATV SCRAMBLER 400 CRANKCASE and CYLINDER - W98BC38C
1998 ATV SPORT 400L CRANKCASE and CYLINDER Sport 400L W98BA38C
1998 ATV XPLORER 400L CRANKCASE and CYLINDER XPLORER 400L W98CC38C
1997 ATV XPRESS 300 CRANKCASE and CYLINDER (400L) XPRESS 400L W97CA38C
1997 ATV XPRESS 400 CRANKCASE and CYLINDER (400L) XPRESS 400L W97CA38C
1997 ATV TRAIL BLAZER CRANKCASE and CYLINDER (SPORT) Sport 400L W97BA38C
1997 ATV SPORT 400L CRANKCASE and CYLINDER (SPORT) Sport 400L W97BA38C
1997 ATV Big Boss 6x6 400L CRANKCASE and CYLINDER BIG BOSS 6X6 400L W97AE38A
1997 ATV BIG BOSS 6X6 400L CRANKCASE and CYLINDER BIG BOSS 6X6 400L W97AE38A
1997 ATV SCRAMBER 400L CRANKCASE and CYLINDER Scrambler 400L W97BC38C
1997 ATV SPORTSMAN 400L CRANKCASE and CYLINDER Sportsman 400L W97AC38C
1997 ATV XPLORER 400L CRANKCASE and CYLINDER XPLORER 400L W97CC38C
1996 ATV XPRESS 300 CRANKCASE and CYLINDER (400) XPRESS 400 W969540
1996 ATV XPRESS 400 CRANKCASE and CYLINDER (400) XPRESS 400 W969540
1996 ATV TRAIL BLAZER ES CRANKCASE and CYLINDER (SPORT) - W968540
1996 ATV SPORT 400L CRANKCASE and CYLINDER (SPORT) - W968540
1996 ATV NORWEGIAN 400L 6X6 CRANKCASE and CYLINDER 6X6 400L W968740 and 6X6 400L Norwegian N968740
1996 ATV 400L 6X6 CRANKCASE and CYLINDER 6X6 400L W968740 and 6X6 400L Norwegian N968740
1996 ATV SCRAMBLER CRANKCASE and CYLINDER Scrambler W967840
1996 ATV SPORTSMAN 4X4 CRANKCASE and CYLINDER Sportsman 4x4 W968040
1996 ATV XPLORER 400L CRANKCASE and CYLINDER XPLORER 400L W969140
1995 ATV 400L 2X4 CRANKCASE and CYLINDER 2x4 400L W957540
1995 ATV BIG BOSS 6X6 400L CRANKCASE and CYLINDER 6x6 400L - U.S. W958740, SWEDISH S958740 and NORWE
1995 ATV SCRAMBLER 4X4 CRANKCASE and CYLINDER Scrambler W957840
1995 ATV SPORT 400L CRANKCASE and CYLINDER Sport 400L W958540
1995 ATV SPORTSMAN 4X4 CRANKCASE and CYLINDER Sportsman 4x4 W958040
1995 ATV XPLORER CRANKCASE and CYLINDER XPLORER 4X4 W959140
1994 ATV 400L 4X4 CRANKCASE and CYLINDER 4X4 400L W948140
1994 ATV 400L 2X4 CRANKCASE and CYLINDER 2x4 400L W947540
1994 ATV 400L 6X6 CRANKCASE and CYLINDER 6x6 400L W948740
1994 ATV NORWEGIAN 400L 6X6 CRANKCASE and CYLINDER 6x6 400L, SWEDISH S948740 and NORWEGIAN N948740
1994 ATV SWEDISH 400L 6X6 CRANKCASE and CYLINDER 6x6 400L, SWEDISH S948740 and NORWEGIAN N948740
1994 ATV SPORT 400L CRANKCASE and CYLINDER Sport 400L W948540
1994 ATV SPORTSMAN 4X4 CRANKCASE and CYLINDER Sportsman 4x4 W948040
1994 ATV W948040 CRANKCASE and CYLINDER Sportsman 4x4 W948040
1994 ATV NORWEGIAN 400L 4X4 CRANKCASE and CYLINDER SWEDISH 4x4 400L S948140
1994 ATV SWEDISH 400L 4X4 CRANKCASE and CYLINDER SWEDISH 4x4 400L S948140 Usage : 3086740

Usage: 3086740
Year Product Model Assembly
2003 ATV TRAIL BLAZER 400 CRANKCASE AND CYLINDER - A03BA38CA
2002 ATV SCRAMBLER 400 2X4 CRANKCASE and CYLINDER - A02BA38CA
2002 ATV SCRAMBLER 400 4X4 CRANKCASE and CYLINDER - A02BG38CA
2002 ATV XPLORER 400 CRANKCASE and CYLINDER - A02CG38CA
2001 ATV SCRAMBLER 400 2X4 CRANKCASE and CYLINDER - A01BA38CA
2001 ATV XPLORER 400 CRANKCASE and CYLINDER - A01CG38CA
2000 ATV SCRAMBLER 2X4 CRANKCASE and CYLINDER - A00BA38CA
2000 ATV SCRAMBLER 400 CRANKCASE and CYLINDER - A00BG38CA
2000 ATV XPLORER 400 CRANKCASE and CYLINDER - A00CG38CA Usage : 3086740

 

You are very helpful sir, and I really appreciate it. All this wasted time because all these Polaris shops told me that they were different. Thank you. Is there anything that I should worry about when joining a non original case half?

 

As long as it fits and seals properly. Granted the cases are sold as a set new,but have had people replace used engine case halves along with transmission case halves.

 

Well Polaristech, I am taking your advice on the engines all being the same. I picked up a 94 2 stroke off of Ebay with 700 miles. It looked super clean, and the price was right. Supposedly it has 150psi on the compression. We shall see. I am happy to be slapping in a eengine that is already together. I couldn't have mine rebuilt anywhere near what I ended up having into this engine, that is ready to go. My next question is, should I go ahead and do a top end on it, or just run it? Also, I want to do away with the oiler. Any suggestions?

 

Just check compression.Should be around 135-140 or so on one that has had a recent top end. 700 miles? All you can do is drop it in,hook everything up,always bleed the 10mm bolt on the head to get any air pockets out of the coolant. Just pull the 3 bolts on the pump cover and check condition of the oil pump.Most problems from the pump was from water intrusion,freezing up pumps. If you wish to premix,just remove the injector hose from the intake manifold,use a smaller length bolt 6mm bolt and washer to block off the intake. Mix at 40-1 ratio. Hopefully you've got a good one.