Rotary mower RPM

Citro-nut

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B4200 Tractor, KH31 excavator
May 30, 2021
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France
Hi, today I fitted a new 3pt lift kit to my B4200, got the mower attached and set up and got to mowing for a couple of hours. I thought the mowar sounded a bit like the first car I ever owned ('64 Triumph Herald) resersing up the road. I was operating in the Low Rpm position. After a while I thought it sounded s lot better, only to find I'd inadvertently slipped it into High. What advise would you give to a newbie? High RPM and therefore lower ground/engine speed or visa versa? I have no data for the mower.
Trevor.
 

85Hokie

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explain "low rpm position" - you have 4 gears - 3 forward and a reverse - and two ranges - high and low.

but none of those settings are rpms! those are simply ground speeds, 1st - you should be setting the engine at its highest engine rpm - wide open - then back it back a bit. Lets say 90% of wot.

Now - if you cut in low range and in first gear - this should cut the best - but it may take forever to cut the grass - you must find the combination that will shoot the grass out and leave the best finish. Engine rpms is more important than ground speed - plus how tall is the grass? taller grass will need slower ground speed to cut well. Depending on the height of grass - you might cut in high range 1st gear or low range 3rd gear. You will see what moving too fast does to the grass!
 

Citro-nut

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B4200 Tractor, KH31 excavator
May 30, 2021
46
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63
France
explain "low rpm position" The PTO has 2 positions, 540 and 860 . But as you pointed out, this is all dependent upon engine RPM, however there is no tacho so I appreciate the instruction, flat out and back a bit:LOL:. I've a mix of tall rough and shorter hand mown, hopefully all of it will become nice and short and manageable in time.
Cheers Trevor
 

Henro

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B2910, BX2200, KX41-2V mini Ex.
May 24, 2019
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Hi, today I fitted a new 3pt lift kit to my B4200, got the mower attached and set up and got to mowing for a couple of hours. I thought the mowar sounded a bit like the first car I ever owned ('64 Triumph Herald) resersing up the road. I was operating in the Low Rpm position. After a while I thought it sounded s lot better, only to find I'd inadvertently slipped it into High. What advise would you give to a newbie? High RPM and therefore lower ground/engine speed or visa versa? I have no data for the mower.
Trevor.
I have an HST and run WOT with the brush hog, and choose the ground speed I like.

I would guess if I had a gear tractor I would do the same thing: WOT and pick the gear that gave me the ground speed I wanted.

Is is there a reason why this would not work for you?

edit: With the pto selector in the 540 position naturally.
 

Citro-nut

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B4200 Tractor, KH31 excavator
May 30, 2021
46
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6
63
France
Is is there a reason why this would not work for you?
I guess not, early days, we'll see how it goes. (y)
 

Russell King

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L185F, Modern Ag Competitor 4’ shredder, Rhino tiller, rear dirt scoop
Jun 17, 2012
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In the USA the input RPM into most implements is 540 RPM so most tractors have that speed pto speed selection and it is usually the slowest speed selection. Some implements and some other countries have a different implement input speed requirement. So you need to verify the input speed required by the gear box on the implement and match that.

The tractor engine RPMs will then really dictate the speed of the pto shaft on the tractor and that is usually near full throttle as mentioned in previous post.

Since you are in France you may have a different implement standard than 540 and need to know what it is. I assume that the engine speed would be similar for all pto shaft output speed.
 

Citro-nut

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B4200 Tractor, KH31 excavator
May 30, 2021
46
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6
63
France
Hi Russell. Thanks for that. I'll need to research the input requirements for the mower. The label on the gearbox is almost impossible to read but I'm almost certain it'll be 540.
Trevor