My '98 YZ400/426F is running strong but there are 2 issue that are concerning me: 1. I'm getting an oil froth/foam dripping from the breather hose once the bike gets warm. After running for 200 miles I was down about 1/8 of a quart of oil (at the bottom of the fill line). What would be the likely cause of this? Also, what grade oil should I be running in this bike? I'm currently using the Motul 10/40 but wonder if I shouldn't be going to 20/50 because of it's age. Thoughts? 2. Once warm I develop a drip of coolant from the overflow and after a days ride I usually find the radiator is down about a 1/2 quart or more depending on the miles/hours ridden. It's only coming from the overflow tube, I recently replaced the impellar shaft and seals and I'm dry there. What do you think the cause is?