Chain Case Instructions

Instructions for installing an extended chain case in a XP/XM

We tried to make it easy for you to install this chaincase. It uses all the stock parts and as many stock mounting holes as we could use. You will need a 2.5” and a 2.16” hole saw, some pop rivets, and normal tools. You will have to find someone who can weld aluminum to fabricate the flange under the chain case. The following is a customer's first-hand account of installing this chain case:

I just completed this project with a C3 Syncrodrive on mine. Here's my Reader's Digest version:


Follow the steps in the service manual (if you don't have one, get one) to remove the jackshaft/secondary and track shaft/track. Grind the heads off the rivets from the inside. The pyramidal chassis structure bolts to a tab on the top of the chaincase. Heaven helps ya to get at the backside. Remove enough bodywork to access the other ends of those rods and disconnect them from the other ends, one near the steering post and the other at the clutch tower. There are miscellaneous other things (wiring and other BS) tied to everything in there so be patient and clear out the space you need. The chaincase and those two cross members will come free as one assembly.



Now take your pick: either this part will make you cry or final assembly will after you've done this wrong. Just kidding-there are some critical bolt holes in the chaincase and clutch side bearing relocator which pave the way for you here; in fact, 3 of the 5 holes in the side of the tunnel lined up and another was almost perfect. The fifth is a bit tricky, more on that later. The horizontal plate will fit exactly where the old one did, you'll drill the holes ONLY after the chaincase sits flush against the tunnel. You'll have to cut the foot boards enough to wrestle the new case into a position where the new bearing cup can sit flush against the tunnel. Cutting the rolled lip off the bottom of the tunnel will be required.


Using longer bolts than what you'll use for final assembly, approximate the location of the chain case such that you can trace around the outside of the bearing cup with a felt or scribe it with an awl. Then you can drill a couple reference holes where the marks terminate at the existing opening. Find something that is the same diameter as the bearing cup, then trace around it using your reference holes from the inside. It's easier to work from the inside of the tunnel. We used a drill, connecting small holes and working our way around for lack of special tools. It's good to have a buddy watch and guide you from the outside. We rounded things smooth with a cone stone.


Once you have the opening enlarged it will bear the rough silhouette of an 8 and you can try lining the case up. There is a lip at the front near the E-module which may hang you up. Grind this down until it's out of the way. You may find that one of the bolt holes toward the rear doesn't quite work anymore now that the case is flush; just chase it with a 1/4" bit. The fifth hole- I got a Canadian tire drill 90 attachment to drill the final hole deep in the footwell. You can now secure the chaincase to the tunnel for final mockup and, using a 1/4" bit drill upwards through the bulkhead drill the 2 holes through the anchor plate.

Disassemble the two chassis cross members from the old chaincase and place them back in the chassis, securing them at their opposite ends. You will use these to determine your hole location on the top tab. Mount them in a forward location relative to where they would sit after final assembly. Remember, if this hole is wrong it will distort the clutch tower. Thread the drill bit through both eyelets positioned on the front of the tab (they will be assembled as stock on the rear afterward) and use them as a guide to drill the hole.

Instructions for 2011/2015 Polaris Pro Extended Chain Case

The first step is to remove the stock chain case/belt drive assembly, suspension, driveshaft, and the clutch side bearing. The chain case is glued on. You will have to warm the glue with a Propane torch. It will then let go. Be sure to heat bolt marked ‘A’. This is threaded into the casting. You will break this bolt if it isn’t heated enough. Be sure to remove the two studs marked ‘B’.

Polaris Pro Extended Chain Case

The next step is to cut along the line marked in the lower left of the chain case opening. You should now be able to trial fit the case. Use the bolt marked ‘A’ and the bolt below it to line everything up. The studs marked ‘B’ can be relocated using the chain case as a guide.

footwell will have to be cut

The footwell will have to be cut as shown.

Clutch side drive shaft bearing

The clutch side bearing relocator has six holes in it. Three of them line up with the stock holes. This locates the bracket. Use the other three holes and a cardboard template to locate the area to cut in the tunnel. Ultimately the gold-bearing plate will be bolted on to this second set of bolts.

cardboard template

The suspension has to be moved down and back 1”. We have supplied you with two aluminum and two steel shims. They are to be installed as shown. The aluminum ones should be on the outside.

chain case

You also have two rear bracket extenders. They should be installed as shown. Be sure to add some bolts or rivets to the top of the brackets.

two rear bracket extenders

Finished pictures

 Finished  product