Hydraulic Requirements for Sabre Samurai mower

[PHPaul]

After spending literally years looking for an inexpensive yet effective way to mow ditch banks, I finally stuck a crowbar in my wallet and sprung for a Sabre Samurai.

I have a B2650 with a rear remote and hoses plumbed to the front for a thumb. The immediate plan is to use that to power the hydraulic motor on the mower.

However, I have some reservations about that as a long-term solution:

1. Will the flow be enough?

2. It seems the motor on the mower is sensitive to speed - several references are made to throttling back the tractor to keep flow to the motor within specs.

3. Not thrilled with cycling the temperature on the tractor hydraulic oil, altho with a hydro transmission, I expect it runs pretty hot anyway. Issue?

4. Not thrilled with tying back the lever on the remote valve as a way of activating/deactivating the mower.

As I said, probably ok for a temporary hookup. I'm thinking of an alternative for long-term as follows:

I have a Prince PTO pump off a log splitter. I'll have to come up with a tank, but thinking the PTO pump with a flow control valve would be a better option. I have enough fabrication skills and equipment to make a 3PH mounted assembly to hold the tank and associated plumbing and I have hoses already plumbed to the front from the rear remote with quick connects on them. Already using them to swap around to meet either front or rear mounted hydraulic requirements.

Assuming I can put a flow control valve on the pressure side of the pump and plumb the return line direct to the tank. Hoping a big enough tank (5 gallons?) will be adequate for cooling purposes.

Am I missing anything or completely off-base here?

 

[Dieseldonato]

It only needs 3gpm so that should be in your tractors pumps wheelhouse. I'd rather have a motor control valve myself, but bungee cording the lever back is an option.
I wouldn't use a log splitter pump, they are typically 2 stage and kick Into low flow high pressure around 700psi. Not ldeal for a hydraulic motor.
Really a 3gpm pump wouldn't be very expensive, hooking it up to the pto is where is gets interesting. Pre made pto pumps are pretty salty in price.
Dan can correct me if I'm wrong, but I would use what you currently have and see how it goes.

 

[PHPaul]

Thanks. Good point about the splitter pump. As planned, I'll do the rear remote thing first. If that gets to be too much of a PITA, I'll see about rigging a suitable PTO pump.

 

[TheOldHokie]

After spending literally years looking for an inexpensive yet effective way to mow ditch banks, I finally stuck a crowbar in my wallet and sprung for a Sabre Samurai.

I have a B2650 with a rear remote and hoses plumbed to the front for a thumb. The immediate plan is to use that to power the hydraulic motor on the mower.

However, I have some reservations about that as a long-term solution:

1. Will the flow be enough?

2. It seems the motor on the mower is sensitive to speed - several references are made to throttling back the tractor to keep flow to the motor within specs.

3. Not thrilled with cycling the temperature on the tractor hydraulic oil, altho with a hydro transmission, I expect it runs pretty hot anyway. Issue?

4. Not thrilled with tying back the lever on the remote valve as a way of activating/deactivating the mower.

As I said, probably ok for a temporary hookup. I'm thinking of an alternative for long-term as follows:

I have a Prince PTO pump off a log splitter. I'll have to come up with a tank, but thinking the PTO pump with a flow control valve would be a better option. I have enough fabrication skills and equipment to make a 3PH mounted assembly to hold the tank and associated plumbing and I have hoses already plumbed to the front from the rear remote with quick connects on them. Already using them to swap around to meet either front or rear mounted hydraulic requirements.

Assuming I can put a flow control valve on the pressure side of the pump and plumb the return line direct to the tank. Hoping a big enough tank (5 gallons?) will be adequate for cooling purposes.

Am I missing anything or completely off-base here?

I would agree with Diseldonato - the tractor hydraulics are more than adequate for that implement. What sort of rear remote do you have - OEM or DIY?

Dan

 

[PHPaul]

I would agree with Diseldonato - the tractor hydraulics are more than adequate for that implement. What sort of rear remote do you have - OEM or DIY?

Dan

OEM, had them install it when I bought the tractor. Smartest thing I ever did, but I wish I'd have had them do two...

 

[TheOldHokie]

OEM, had them install it when I bought the tractor. Smartest thing I ever did, but I wish I'd have had them do two...

The OEM valves are sectionals so adding another section is real easy. I dont think they offered a motor spool but locking detent might be available. Cleaner thsn a bungee cord but a whole lot pricier.

With a little creative plumbing you could add your own valve to the circuit for a lot less.

Dan

 

[PHPaul]

The OEM valves are sectionals so adding another section is real easy. I dont think they offered a motor spool but locking detent might be available. Cleaner thsn a bungee cord but a whole lot pricier.

With a little creative plumbing you could add your own valve to the circuit for a lot less.

Dan

Good point, I'll look into that.

 

[TheOldHokie]

Good point, I'll look into that.

I have looked at the parts diagrams for the OEM remote valves but but I am not exactly clear on how the loader power beyond pipe fits into the plumbing. If you could post a top view picture or two of the remote valve I might be able to offer some more thoughts.

Dan

 

[PHPaul]

It's a cab tractor so access may be an issue, but I'll see what I can come up with. I'm VERY interested in a second rear remote as I'd love to have top-and-tilt for my box blade anyway.

 

[PHPaul]

Best I could do. Looks like it'd be an aggravating project!

 

[TheOldHokie]

It's a cab tractor so access may be an issue, but I'll see what I can come up with. I'm VERY interested in a second rear remote as I'd love to have top-and-tilt for my box blade anyway.

Well nothing is easy when working with a cab tractor so don't worry about the pictures. The B2650 loader valve and plumbing is similar to the B2601 but I can't find info on an OEM remote kit for it with or without cab. Here is what they are using on the B2601 with ROPS. Any similarity to what is on your B2650?

Dan

 

[GreensvilleJay]

Curious, so I downloaded their install sheet.
1st they say 10GPM@500PSI, then later 3.3GPM@500 PSI then 'adjust for blade slower than a blur'....
For sure I'd install a 'flow divider', once set (say to 3.GPM to unit) it shouldn't ever need changing.

 

[TheOldHokie]

View attachment 85146

View attachment 85147

Best I could do. Looks like it'd be an aggravating project!

Looks like our posts crossed. That looks very similar to the B2601 setup and aggravating is putting it mildly. Whats up front for the third function? That might be an easier way to tap into the flow especially since I just looked at the manual and now see how the Samurai mounts.

Dan

 

[TheOldHokie]

Curious, so I downloaded their install sheet.
1st they say 10GPM@500PSI, then later 3.3GPM@500 PSI then 'adjust for blade slower than a blur'....
For sure I'd install a 'flow divider', once set (say to 3.GPM to unit) it shouldn't ever need changing.

The manual provides pretty detailed specifications:

• The motor displacement is 3 cubic inches/revolution
• Maximum allowed motor speed is 500 RPM.

Doing the arithmetic maximum permissible flow is:

3 ci/revolution x 500 revolutions / minute = 1500 cubic inches (6.5 gallons) per minute.​

They suggest an actual operating speed of 400 RPM or less which is roughly 5 GPM. Since 5 GPM is the maximum the B2650 can produce I don't see any need for or benefit from flow control other than engine speed.

Dan

 

[GreensvilleJay]

According to the datasheet, the B2650 is supposed to have 8.7 GPM flow and 'SAM' needs a MAX of 5 GPM.
How do you 'get rid ' of the extra 3.7 GPM of oil ? If you reduce engine speed to reduce flow, you'll change how the tractor performs. Wondering is the 8.7 is at max engine RPM or at the '540' mark ?
Mind you as cutting grass is a slow operation, may not see the need for higher engine RPMs ?

I did see that while the motor is listed as FUMA7191, ,they spec a Char-Lynn 101-1001-009 as a replacement.

 

[TheOldHokie]

According to the datasheet, the B2650 is supposed to have 8.7 GPM flow and 'SAM' needs a MAX of 5 GPM.
How do you 'get rid ' of the extra 3.7 GPM of oil ? If you reduce engine speed to reduce flow, you'll change how the tractor performs. Wondering is the 8.7 is at max engine RPM or at the '540' mark ?
Mind you as cutting grass is a slow operation, may not see the need for higher engine RPMs ?

I did see that while the motor is listed as FUMA7191, ,they spec a Char-Lynn 101-1001-009 as a replacement.

I think your data source has you confused - possibly giving you total flow rather than implement flow. This is the official Kubota specification for implement flow on that tractor and its 5.3 GPM. Set engine RPM at 540 PTO speed just like you would for mowing and you are good to go.

Dan

 

[GreensvilleJay]

Thanks for the info !
...the spec I read is from the 4 page datasheet, which sadly doesn't even have the pressure listed either, 2300 psi +- from your source.
I did 'assume' the '540' speed even though it's not on the page.

 

[Dieseldonato]

Thanks for the info !
...the spec I read is from the 4 page datasheet, which sadly doesn't even have the pressure listed either, 2300 psi +- from your source.
I did 'assume' the '540' speed even though it's not on the page.

The spec you found likely includes the power steering flow as well as implement flow.

 

[TheOldHokie]

The spec you found likely includes the power steering flow as well as implement flow.

Kubota tends to advertise two numbers:

• Total flow which I assume is the total output of all pumps and includes the steering system.
• Implement flow which is the portion of the total flow that is available to an external implement like a loader or backhoe.

Dan

 

[bird dogger]

I also ordered a Samurai Sabre Cutter a week ago. It'll sure earn its keep around here. I'm hoping it will run just fine off the 3rd function hookup on the loader. If pressing/holding the button on the 3rd function handle is awkward, I'll try adding another switch in parallel with one of the 3rd function "operate" coils.