February 5, 2009
Installing Black Diamond’s Pro Lite Series Rear Bumper kit
By: jacob white
Shedding weight wherever possible is pretty much numero uno on our to do list. But finding parts that cut weight and improve a sled’s ability to go through deep snow is always a bonus.
Since the Arctic Cat M-Series has been out (2005), the chassis has had wide runningboards that run the full length of the tunnel. As the years went by, engineers figured out that running boards act like a shelf when the track is trying to dig down to firmer snow as it claws through deep powder. So for 2009, Arctic Cat modified the tunnel on the M-sleds, hacking off the rear most portion of the runningboards and tapering the tunnel up at a steeper slope. The difference is astounding.
But if you’ve got an ’05-’08 M-series sled, you’re SOL, right? Not quite.
Black Diamond Xtreme has designed a kit (offered well before Cat released the 2009 models, by the way) that makes the same modifications to the tunnel of your M-series, giving you the deep snow mobility that comes from not having those wings hanging up in deep trenches.
We installed a BDX Pro Lite Series rear bumper kit on a 2008 Arctic Cat M8. Follow along.
1) This is the before picture, showing you a couple weaknesses in the OEM design. First, the rear bumper is not something we’d claim to be durable.
2) From this angle you can see how the running boards to end eventually, but not until the tunnel ends, too.
3) The first thing to do is remove the stock tail light and rear bumper assembly. Keep them close by, since you will be reinstalling a few parts off of it.
4) You have to remove three rivets from both sides of the runningboard. These are the three that are furthest back.
5) Next, cut out the template supplied with the bumper and place it on the running boards, lining up the three rivet holes you just drilled out with the marks on the template. Mark along the edge of the template with a black marker, going all the way around the edge roll.
6) Following the angle of the template’s mark, carefully cut the running board from the edge roll to the side wall.
7) File off a couple rows of edge roll grip tabs. This is done so that the new footrest can sit flush on top of the edge roll.
8) Next, mark the angle of taper you are going to wind up with by going from just above the cut in the tunnel side wall to the rear of the tunnel. Our M8 had these windows cut in the tunnel near the rear, so we made our marks so that the new rear bumper would just cover those windows. Make your cut carefully, avoiding expensive stuff, like heat exchangers and track lugs.
9) We broke out the surgical equipment to make this cut next to the heat exchanger tube. The last thing you want is a simple bumper install to turn into a coolant reworking job.
10) Theoretically, you could ride it this way. Just don’t get stuck, and don’t stand on the running boards.
11) Now mount the footrest by first drilling out the holes and then riveting the footrest in place by coming from the backside of the tunnel.
12) There are three rivets behind the tunnel, one on the edge roll and three through the bottom of the runningboard and footrest.
13) Next, mark and drill new holes in the OEM snow flap.
14) Mark, drill and insert the new crush nuts that are supplied in the bumper kit for mounting the snow flap.
15) Mount the snow flap to the tunnel.
16) To make the tunnel edge sit into the bumper, we had to cut away some of the bracket that holds the cooler tubing.
17)Now place the bumper on the sled making sure that the tunnel edge sits down into the groove in the bumper and that the front edges of the bumper sit flush against the footrests. Begin fastening the bumper in place by drilling through the back side, going through the tunnel edge first and then into the hallow cavity of the bumper. Rivet from the front back, keeping the bumper pulled tight up against the tunnel as you work your way back.
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