Recently I purchased a used 2000 WR400 for what I thought was a good price of $3300. The only problem that I was aware of were slightly leaky fork seals that have since been repaired. Now I've learned that it burns oil. A small amount of blue smoke can be seen for about a minute on cold start. Once it warms up I never see any more smoke. Post purchase diassembly revealed that the previous owner ran stock jetting and WR timing with a FMF power core IV slip-on and no airbox lid while ice riding in the winter in Michigan. Now the bike burns about 1/2 of the oil tank dipstick level between full and add in about 10 miles of trail riding. Any suggestions.