Yanmar tiller: Changing rotor speed??

LD1 · Jun 4, 2013

Got a used yanmar tiller. Not sure but I think the model number is 4654T, thats whats stamped on a plate.

Anyway, the tines dont seem to rotate too fast. At least not like a KK I have used. And it makes it about impossible to till with an 8n, as ground speed is too fast. It seems the tines are just barley out running the drive tires.

Anyway, its a gear drive tiller. And I havent had a chance to look into it too much, but are the gears possible different sizes in which can be changed around to get a faster speed?? There are 4 gears, the drive, two idlers, and the rotor gear.

Only other option is possible swapping gear-boxes.

And does anyone know off hand what KK rotors turn @ 540RPM?? That would also help if I do choose to get a new gearbox.

Heres the pics

fordoutback · Jun 4, 2013

You aren't going to be able to use any tiller on an 8N unless you have the super-rare "rotorvator" attachment. Even with a Sherman Hi-Lo, an 8N is just geared too high too till. The rotorvatotor isn't actually an attachment, but a transmission that makes the 8N longer. They are extremely rare.

LD1 · Jun 4, 2013

It has a sherman.

Have used it before with a kk tiller. No issues. The KK tines turned faster than this tiller does at 540rpm.

crazyal · Jun 5, 2013

Have you thought about a PTO multiplier? It sounds like the tiller is set up for 1000 rpm pto.

LD1 · Jun 5, 2013

crazyal said:
It sounds like the tiller is set up for 1000 rpm pto.

Thats possible?? Its got a 540 ptoshaft on it though. I know that could have been changed?? Thats why I'm trying to atleast ID the darn thing and see if I can find some info on it.

I guess I have never heard of a PTO multiplier either. I'll have to do some googling I guess.

LD1 · Jun 5, 2013

Looks like I at least figured out what model tiller it is.

Its a RS1400k. IT also has tines that dont quite look like other tillers. They seem longer and more C shaped without as much of a bend to them?? Not sure quite what those are for.

But back to my initial question, given that there are 4 gears in the drive unit, is there possibly a way to change the combination to get at different speeds?? Kinda like changing gears on a lathe?? I cannont seem to find a "free" manual for this thing anywhere on the WWW.:mur:

Car Doc · Jun 5, 2013

Hey LD1 the Yanmar tractors that was designed to run with had 3-4 speed ptos may explain why is slow on a 540? Nothing a guy can do except maybe switch gears around in the gear case if they would even fit in different order elifino? edit; Oops I see where we are thinking alike you posted my suggestion already! :laughing:

LD1 · Jun 5, 2013

Yea, tiller is over at mom and dads right now. He uses an 8n. A KK that my grandmother had worked well on his tractor. This on...not so much. Tines are fast enough, just not in relation to his ground speed. It works fine on my kubota.

I was hoping someone would know for sure if gears can be swapped around on this thing or not. If the top gear (drive) happens to be smaller than the driven gear, I could swap them out. Which would also require swapping the two idlers, and providing spacing will work out okay. But of someone knows for sure if it wont work, I wont waste my time trying.

Other options I was considering...just getting a $100 chinese gearbox for the tiller to step it up, if I can find one with the right shaft sizes and configurations.

The oversized 12.4x28 tires on his N arent helping either.

crazyal · Jun 5, 2013

If I remember correctly that tiller could be one that came over with a grey market tractor. The "J" style tines are used in rice fields. I haven't seen many but the ones on your tiller could be worn.

If it was me I would figure out what gear reduction is in the angle gear box and then what reduction is in the side gear box. Once you know the total reduction you'll know what speed the tiller is running at now with a 540 rpm pto speed. Potentially either one may be reversed. I would then use the 540 rpm to see what new speed reversing one or the other will give you. It's possible that the drive and driven gears in the angle box can be reversed. I haven't taken apart many of them but the few tractor ones I've done could be reversed.

LD1 · Jun 5, 2013

crazyal said:
If I remember correctly that tiller could be one that came over with a grey market tractor. The "J" style tines are used in rice fields. I haven't seen many but the ones on your tiller could be worn.

If it was me I would figure out what gear reduction is in the angle gear box and then what reduction is in the side gear box. Once you know the total reduction you'll know what speed the tiller is running at now with a 540 rpm pto speed. Potentially either one may be reversed. I would then use the 540 rpm to see what new speed reversing one or the other will give you. It's possible that the drive and driven gears in the angle box can be reversed. I haven't taken apart many of them but the few tractor ones I've done could be reversed.

Thats another good suggestion.

Its hard to say, but from the parts list I was able to find, it did look like the driver was smaller gear than the driven. I was contemplating just re-mounting the gearbox (if input and output shafts were the same), but I will explore the option of just swapping the gears inside first, as that would seem easier than re-configuring the gearbox mounting.