So I know that the Mach 1 and Mark 3 are very similar bikes, my specific interest is in the tank. I have seen some older M1 tank pictures where the right side of the tank literally has a scoop missing just behind the petcock (very visible from a side view). I have also seen M1's and MK3's that boast the wonderful 29 ss1 delorto, but do NOT have that "scoop" out of the tank.
I recently bought a bike and yes it has a 29 SS1 delorto, however I can not tell if the tank is a true M1 or MK3. There is no missing scoop visible from the side, BUT...the underside is not symetrical in its construction; the left looks to be standard straight in back then curving around the "head," while the left starts out at an angle from the back leaving what seems more space?
I wish I know how to post pictures...I will have to work on that.
Cheers,
Merlin
Mach 1/ Mark 3 tank...
Mk3 tanks were similar in design to a number of other tanks (early Diana, GT, one year of the Sebring, one 200 model) The diana tanks were wider and carried more fuel. I've heard these described as " the five gallon tank". The Mk3 tank was the narrower version "the four gallon tank". Ducati took these catalog tanks from the vendor that made them and had their "craftsman" beat a dent into the underside of the tank to clear the carb. Then they brazed the seam where the tunnel of the tank was welded to the tank. I've seen a number of tanks dented this way so I have reason to believe it was a factory modification.