Hey Multimiler,
The 725 is most like the current 722. I assume you mean 732 for the other comparative model as the 735 is the same era as the 725. It is not like the 732 because it does not have locking differential. Depending on the condition of the tractor and attachments, I'd consider the $2600 price to be on the high side of fair. When I come across a used BCS to sell, I consider spline PTO, solid axle tractors to be worth around $600, a spline PTO tiller to be $300, snow blower around $400, blade $250, and mower $500
The 725 has a two stick shifter that gives it 5 speeds forward and 2 speeds reverse in tiller mode. As with most walk-behind tractors, when you reverse the handlebars, the reverse gears become the forward gears in mower mode. This means you will have 2 speeds forward and 5 speeds reverse. The shifter is set up in such a way so that you can access only the first gear hi/lo when in mower mode. The other gears are useless because they are all reverse in mower mode.
The PTO is the older grease-filled slider on a spline shaft. I disagree with John that this is a weak design. It worked for both BCS and Grillo from the 70's into the mid-90's. The reason BCS went away from it is twofold. First, they came out with this terrible 30 inch mower with a solid blade. It was a glorified lawn mower, but they billed it as a rough-cut mower. As long as you stayed in relatively clear running with no trees, brush, or rocks, you'd do fine. The moment you hit hard material, the solid blade would transfer all the stress through the transmission to the weakest link - which would have been the clutch, and it would slip until disengaged or the engine killed. However, at the same time, BCS started coming out with larger engines to satisfy us Americans desire for "more power!". To accommodate engines larger than 10 hp (which had been fine up to that point), BCS came out with a very strong cone clutch. Too strong, it turns out. The clutch wouldn't slip when the mower hit hard objects. The next weakest link was the PTO coupler. First, they tried a 3 dog flat faced PTO on the 605s and 737s, but then they completely changed the PTO engagement to be internal and went with a tapered 3 dog PTO. Had they stayed with the smaller, adequate engines, the weaker, but effective clutch, and not come out with that terrible mower, they very well could still be using the same PTO that had served well for decades. If the brush mower you mentioned is a 30" model with a round shroud, be VERY careful with how you use it.
You have another tiller option that John didn't mention. The Grillo tiller will bolt directly onto the 725's PTO. PTOs are the same RPM, same shaft size, same bolt pattern - no $60 adapter. It is $500 for the 22 inch tiller and it is a far superior design versus the current tiller offerings from BCS. It has bolo tines that are bolted seperate to the hubs in a helical pattern, a larger, stronger gearbox, and a better, more positive depth control.
Good luck with the machine, they're excellent tractors.
