PTO rear shaft upgrade ?

[Kerryman]

Hi guys. Do my orange is a b7200. Very clean for its age (better than me ) and I have fitted a mower deck to it, A 54” Kubota deck RCk54--22BX via the rear 3 point linkage.
Only problem is the mower isn’t spinning fast enough to slice the grass. More like it’s pulling it. I have it set in high pto speed (825)) with the engine at 2800 revolutions (high). Running in 2nd low gear. The grass is getting cut but not right. Blades are super sharp.
My local dealer maintains I cannot change the pto shaft to increase the speed.
Any thoughts out there ???

I have a donkey who will eat the grass eventually

 

[mikester]

men are men and the sheep are nervous...

 

[rc51stierhoff]

Good day.

I am not familiar with your machine at all. I wonder how do you know the blades aren’t spinning fast enough?

Blades are installed correct direction, correct? Belt tension good? All blades spin properly? Etc.

 

[GreensvilleJay]

If I read this post correctly, you took the MMM and put it onto the 3PH ?

There are 2 issues when you did this.

1) RPM. MMM (front PTO) spins at 2000-2500 RPM, PTO is 540.

2) DIRECTION of rotation. the blades could be spinning backwards !

#2 is easy, #1 is pricey

#2 )pretty sure the PTO will spin CCW ( to the left, from 12oclock ) ? If so, MANUALLY spin the PTO shaft and see if the deck blades turn the CORRECT way.

#1 ) buy and install an 'increaser' gear box. Yes, they are available, or make your own. essentially a large gear powered by the PTO, that drives a smaller gear which powers the deck. A 4:1 ratio seems 'good'.

 

[Sidekick]

I think the BX mid pto spins at 2500 rpm at 3200 engine rpm. There's pto speed increasers available if you search. Also I have seen people switch the gearbox gears to the set from the zero turn to increase tip speed. Start increasing pto speed and hp will suffer with inefficiency. Probably be cheaper to find a used finish mower.

 

[TheOldHokie]

Hi guys. Do my orange is a b7200. Very clean for its age (better than me ) and I have fitted a mower deck to it, A 54” Kubota deck RCk54--22BX via the rear 3 point linkage.
Only problem is the mower isn’t spinning fast enough to slice the grass. More like it’s pulling it. I have it set in high pto speed (825)) with the engine at 2800 revolutions (high). Running in 2nd low gear. The grass is getting cut but not right. Blades are super sharp.
My local dealer maintains I cannot change the pto shaft to increase the speed.
Any thoughts out there ???

I have a donkey who will eat the grass eventually

Your mid-mount mower wants 3X the 820 RPM of the B7200 rear PTO. Buy a 3pt finish mower. Its probably less expensive and definitly a lot easier than stepping up the drive ratio on the mower.

Dan