Because your pedaling too fast...
oil leaking out of the muffer and the air filter oil leaking out of the muffer and the air filter oil leaking out of the muffer and the air filter oil leaking out of the muffer and the air filter
You probably have a damaged fork oil seal, which needs replacing.
that's normal.
If you were to use brake cleaner it will clean all the dirt and oil off of it.
Yes there is no difference. I would however recommend you use synthetic oil in a motorcycle especially an air cooled one.
The oil filter is in that area behind the air cleaner box, it could be leaking around it's gasket or loose. The oil cooler lines and lines leading to the engine could be leaking too, they are sealed by o-rings which you can get at an auto parts store as an oil cooler repair kit.
Additionally information- new crush washer used not overtorqued/pan not stripped
Bad PCV valve.
An oil bath air cleaner can be maintained at little cost.
Unscrew the oil cap on the valve cover on the right hand side of your air cleaner it attaches to the air cleaner. Al Cauchon
Your oil filter is located behind the air cleaner on the Driver side wheel well close to the drivers side headlight, remove the air cleaner housing to get to it.
There is a small chrome breather tube going to the air cleaner from the oil tank. After the bike sits all the oil drains down to the tank and when you first start the bike because of the low volume oil pump the some oil goes through the breather and into the air cleaner. you can go to a dealer they have a kit to fix that problem.