Yes that is a 990885 which was the first mower they made specifically to fit the RBT's That is the same mower that was on my 3414 and the donner of the arbors and rollers to my "new" mower deck that Biggie Rat so graciously gave me. BTW, I think you did a super job on the conversion. So it is shaft drive to the mower than a belt runs the deck arbors. That is a great way to isolate the tractor drivetrain from the mower shock. I support the pto is belt driven through the front axle pivot. You picked a top notch mower.
Phil
"They that can give up essential liberty to obtain a little temporary safety deserve neither safety nor liberty."
Putting that much effort into adapting the deck without knowing if it was going to work was the worst part. If I had to do it again it would go much faster of course but would have liked to do a better job of blending in where the original discharge chute was closed off.
Thanks Phil. I have had projects in the past that turned out to be a total waist of effort, fortunately this is not one of those and almost hate to quit mowing with it. The little Yanmar chugs along happily and is by far one of the quietest engines I've been around. For last couple of weeks it has rained almost every day and it looks like next week will be no different. Lots of grass to mow. Yes it is belt from the engine to the PTO shaft. Then shaft to the gear box which is mounted on the deck support frame. Then from the gearbox is a belt to the blade arbors. Routing the blade belt without rubbing on anything was a head scratcher.
East Central South Dakota
The democracy will cease to exist when you take away from those who are willing to work and give to those who would not. Thomas Jefferson