My '99 Scrambler 4X4 needs an engine rebuild. It looks like quite a chore to get the engine out especially with having a front driveline etc to mess with. Is it possible to rebuild the top end with the engine in the bike if you pull all of the front plastic, fuel tank etc off? Has anybody done this? Would i just be better off pulling the whole thing out? Any insights to if this is possible or about rebuilding these in general would be greatly appreciated [img]i/expressions/face-icon-small-smile.gif[/img]

 

If you dont have a Polaris service manual, Id suggest getting one before you start the rebuild. The manual says that you can rebuild the top end with the engine in. Its not much to remove the plastic and tank. You will probably have to in order to rebuild it.

 

I have the top end off of my Xplorer 400 right now and all I had to remove was the front plastic and the tank.

 

It's really a lot easier than you think. More darn screws in the plastic than anywhere else.Bubba

 

I rebuilt mine while it was still in the frame. It actually made it easier. The engine won't budge while your working on it, because it is in its own "vice" if you will.

 

Thanks for the help guys, got it torn down easily. A cylinder bore and new piston are next. Was wondering if anyone by some chance has the page or pages from the service manual that deals with removal of the piston from the rod and reassembly including the torque specs scanned in that they could email me? I plan to buy the manual but right now coming up with the money for the rebuild is going to be tough enough as it is.

Thanks for any help anybody can offer [img]i/expressions/face-icon-small-smile.gif[/img]

 

The specs are easy. The base bolts go to 24ft/lbs and need to be rechecked after a warm up and complete cool down. The head bolts go to 18ft/lbs naturally in a criss cross section. Dont add sealer to the base gasket or head gasket, and I always use the OEM base gasket. They are far superior in quality.To get the piston off the rod, remove a circlip off one side (stuff an old shirt or towel in the open crankcase to keep stuff out). If you dont have the pin tool, have someone hold a block of wood against the piston side and use a small socket a hammer a gently tap it out. They usually dont give problems. The new one will go in no problem. All the work can be done in the frame. Done pull the motor on these unless its a have to case. You have to realign the clutches if you do.It wont hurt to pull the top motor mount,just put it back where it was. I forgot to tell you in that PM, take about .015 off the head too. That will help the low end out and boost overall performance a touch.Bubba

 

I believe Bubba has the torque specs backwards. The base bolts should be 18 and the head bolts should be 24. Rechecking after warm up and cool down is critical also. Olav Aaen also recommends a thin layer of silicone on both sides of the head gasket.

 

I just put my cylinder and head on last night and the tq specs in my polaris maintenance manual said 28 ftlbs for the cylinder and 20 for the head. This is for my xplorer 400.

Bubba,
I was wondering about using a sealant on the base gasket and did not see that there was any sealant on it when I removed it so I all I used was the OEM gasket. Glad I made the right guess. Hopefully with another night of wrenching I'll get this baby fired up soon.

 

I stand corrected you did it the correct way sorry. Good luck