I dunno if mountain bike experience will play big here, but on my Norco Bigfoot, I tried a cleaner/oiler gear clip on thing a while back, worked great as Shewolf said, on the street, but as soon as I got even SLIGHTLY off road (the park trail down to the sailing center) the thing bunged itself up, took forever to free and I had to get a new chain and front derailer...
Me personally, I wouldn't risk it, since the same respective components on a WR could mean rebuilding the engine, just a thought.