YT6700 transmission

[Meofouse]

Is anyone parting out a machine that would have a transmission to fit the 6700? It has the Daikin BDV-10S-5455. A used one or a parted out one might work. There is a bearing and some pump tubes that I need.
Meofouse

[Meofouse]

An update on the transmission for the YT6700 series. The Daikin line of hydrostatic transmissions in this unit is now serviced and supplied by Sauer Danfoss. Here is a link to the technical information and drawings of this pump
http://www.sauer-danfoss.com/stellent/groups/publications/documents/product_literature/520l0935.pdf

[rattosh51]

Good info to know Meofuse...thanks.

[Meofouse]

Does anyone know if hydros from any other Yamaha models are interchangeable? Is anyone parting out a machine? I'm beginning to think I might have to somehow install a JD drivetrain or make a manual setup with pullys and belts. I've been running into blank walls looking for a transmission or parts, it seems that Yamaha only made one YT6700 and I have it. My neighbor thinks we could make a fast go-kart with the engine and wheels

[Meofouse]

Finally found a Yamaha dealer in my area who knew that Yamaha even made a lawn tractor
Most of the shops only deal in atv, cycles, shomobiles, outboards or musical instruments
The dealer had a partial breakdown of the transmission area but the hydro unit itself is n/a
If it was available the price at the time was $896.
I went to a local bearing company and was able to order a bearing that would fit what I need and some spacer races to make up the difference in proportion required for a total cost of $37.00
After I put the unit back together I will post to let you know if these units can at least be repaired with some "field engieering" and post sime pictures of the process.

[Meofouse]

Finished cleaning up the hydro and installing new thrust plates and bearings for the pump side of the hydro. The swash plate race was pitted beyond repair so I installed a new thrust washer over the old groved race, added a new thrust bearing and polished down the original pump face plate. The faces of the pump cylinders were scored and pitted also so they also had to be polished to a mirror finish. Here are some pictures of the procedure. Lots more pictures if anyone is interested. These pics have been downsized for the net but I have 26 pictures of the entire build in very fine detail and closeups. The one picture is of a small fraction of the metal filings that were removed from the oil passages. The entire unit was flushed with lamp oil, cleaned with carb cleaner and blown out after soaking. The problem was caused by lack of maintenance of the hydrostatic unit and I would strongly suggest annual oil changes. Not an easy job but sure beats a rebuild.

[rattosh51]

Great pics, Meofuse, thanks. Please send those on to me so I can get a better look. Good tip about the oil changes too...I'm going to try and change mine this weekend. Glad you got it back together again!!!

[Meofouse]

Hopefully the last post on the Yamaha hydro. Repaired and installed. Running great, like new. It took some effort the get the flow passages recharged. After installation it was necessary to pull the tracter backwards without the engine running and without the by-pass engaged. It went about 6 feet before resistance was felt and the wheels finally locked up. Same thing in forward. After starting there was some groaning while air purged the system. Back on the road again. I believe there is a way to drain and purge the hydro without complete teardown. There are three flow valves that can be removed on the bottom side of the unit with an allen wrench. If those valves, small springs and ball bearings, are carefully removed the old oil will drain out, albiet slowly but it will happen. Flush the unit with kerosene several time and refill with oil until it drains out of the valve openings and then replace the valves. Some effort required but less than looking for parts and field engineering new internals.
Now to the gunky carbs which make it hard to start.
I will begin a new thread on those, with pictures if anyone is interested.