They air for the forced induction for the yosh airbox. See pic below. Sorry for the distracting features. Old Skool for sure. Special upperfairing that I believe you can still get fron Airtech . Hopes this helps answer your ?
The hoses look to be in the right place on the top, but you can see some rust around the tubes. The Yosh tanks were Alum. Lots of knock of Racer look tanks out there. I have one knock off in the garage already and am high bidder on this one. If he sends me picks of the bottom of the tank I'll know if it is real or knock-off.
It does not have the flat bottom of the Yosh tank so not done by them. I did not know yosh sold a kit to modify the stock tank. I don't remember it in any of the catalogs but that does not mean anything. I can't check all my reference stuff as it is a race weekend and it is all 300mi away. Did pretty good with the DRZ400SM in our under 500cc class. Did not get into the top three but at my age and concidering I broke my Index Finger on my Right hand, so was racing with a Splint tapped to the outside of my glove... I had fun.