Does anyone know if the crankcase on a 400 can be flushed out? My piston shattered and I can see alot of really small pieces have fallen into the crankcase. Am I gonna have to open the case or can it just be flushed out? I can't find any drain plug other than for the counerbalance oil. I don't want to have to crack open the case but if I have to I have to. Please somebody tell me theres a way to just flush it clean.

 

I hate to be the bearer of bad news , but , here goes . Tear it apart , and even remove the main bearings , pieces will be between the seal and bearings , and also look for a broken case .

I have seen guys flush them and get away with it , and I have seen folks bit by not doing it .Do ya feel lucky ?

 

If there are shavings, you really should crack it open. If it's only pieces you can flush it with deisel (which will work as a lubricant), but you'll probably have to remove it to dump the deisel and piston pieces out. Not drain it thru the drain plug.

 

What Piston did you have? Was it a stock Polaris "Yes they will break" piston?

 

Well, after turning my crank by hand and looking down in there I thought if only I had some type of vacuum line I could just suck the stuff out. I ended up going to Home Depot and buying their smallest 2 gal. shop vac. They sold a mini accessory kit for it that contained several long vacuum tubes not much bigger around than a pencil, one was even bent at an angle. They fit down thru the gap in the middle of the crank and I was able to suck up everything in the crankcase.
Then my son sprayed it all out with brake cleaner with one of those flexible plastic tubes while I spun the crank and then I sucked it all out with the vacuum. I then blew it all out and vacuumed it again. I checked it out with a flashlight and it was spotless. My son who had insisted I was going to have to open up the case couldn't believe how clean it was. I then oiled it up real well and the crank turned smooth as silk. I couldn't believe how well it worked. It may come back to haunt me but I have it back together now so only time will tell.

 

You COULD just fill it with parts cleaner, blow it out with an air gun, then fill it again, then blow it out, repete again and again untill you feel NO resistence what so ever in rotating the crankshaft. It should turn like butter. Also blow out the lower rod bearing as well. But the "Do you feel lucky?" post before me really does say alot [img]i/expressions/face-icon-small-wink.gif[/img] Very fine aluminum -dust- still in the case can cause minimal bearing, piston and cylinder wear. I have blown out cases before with no problems but you'll always ride with the thought in the back of your head... "What if" If your only riding in your back yard, hey. Go for it. If your riding all over the county trusting your machine, do a full rebuilt. It never hurts to have a nice set of crank seals in there anyway. Piece of mine you know.