I hope this Bombardier forum will grow into a busy site someday.
When I got involved with my Snow Trac what I found was that there is a lot of information, but very little of it is easy to find. So I set a goal to find Snow Trac owners, and gather the information and then put it into a format that could be easily shared. What I found along the way is that there are a lot of snowcat owners representing a lot of different brands that had the same needs that I had. While I love my little Snow Trac, I consider snowcats in general to be my hobby. I enjoy helping anyone who has the same interest, sharing information and promoting other sites.
To make this site grow what you need to do is find members. Like you my site started out as a single brand site but that changed over time, and it has had both drawbacks & benefits. One thing that I'd like to suggest is that you cannot wait for people to find you, you have to do things to attract members.
The Wikipedia concept is a win-win concept because it helps Wikipedia + it helps people find you.
You might want to work with parts dealers and ask them to direct people to your site as well. That is another win-win concept. The dealers benefit because they sell parts to people and your site provides the dealership's customers support for repairs.
Think unconventionally and focus on having fun. That is what we are all here for and that is why we go play in the snow.