Welcome to the forum! When you get a chance, please introduce yourself in the introduction portion of the forum. In the mean time, here is an older post with the info you need.
If you find yourself with a leaking primary cover first thing to check is the Primary Case Vent which is easy to get at with a 7/16" wrench (be carefull as some are nylon). A friend had a small leak in his primary and after installing a new clutch and cable I also removed the primary vent...
www.bigdogbiker.com
BDM had a Service Bulletin (SB-1062) in Sept 2005 that added the vent button on the back of the inner primary due to the vent in the cover being a failed design. If im not mistaken, they also removed the sponge and oring and added the flat paper gasket the following year. You had to use rtv with the original flat gasket but the material has now been upgraded and no longer requires rtv per the attached Service Bulletin.
On a side note, the recommended primary oil quantity has also changed on the 05-up. The recommended 32 ounces worked fine in the older Big Dogs since the primary was actually larger. Since 2005, we have all seen a ton of failed starters due to primary oil getting into them. The cutout relief in the starter is supposed to allow the oil to drain back into the primary but it also seems to be a flawed design.
The clutches that came in our dogs are made by Energy One and per them, can be ran with no fluid. The only reason we need primary fluid is to cool the chain. 18-20 oz non-synthetic dyno is now the recommended amount.
