6' Agmate Finish Mower modification & tune up

[TractorGuy]

I will preface this post by saying I saw no real difference in mowing quality afterwards. To make a clean one pass cut in Pensacola Bahia you need a faster blade tip speed than you get with most finish mowers. There may not be a mower that can achieve a clean one pass cut in Bahia.

The Agmate 6' finish mower has an advertised blade rpm of 2223 but my calculations with their advertised gear ratio works out to 2180. This is a blade tip speed of 13,690 feet per minute. I did a little checking and found out their 4' mower used the same gearbox, spindles, and belt pitch but has a larger gearbox pulley. The 5'&6' mowers have a 7.864" pulley while the 4' mower has an 8.5" pulley. Not a huge difference but I figured any increase in blade speed might improve the cut quality. I was able to install the 8.5" pulley and use my same belts. I had to get the belts in the pulley grooves with the gearbox mount loose but after getting all the bolts in and tight I still had to use the tensioner to tighten them a little. I won't go into all the math but it increases the blade tip speed from 13,690 FPM to 14,820 FPM.

I noticed while it was sitting on a level surface with an equal number if spacers on each wheel the deck was a half bubble higher in the front so I took out a 1/2" spacer from the front wheels to get it dead level. I also installed new blades. Also the pulleys are slightly different in construction. I measured the belt groove distance from the gearbox mount and found I had to remove the two washers that were installed under my existing pulley to get the same belt alignment.

When mowing the thicker areas I did hear some change in engine sound which I rarley heard before so it is laboring the tractor a little more. My little tractor only has 19 PTO HP so I think I found the limit on it with a modified 6' finish mower. The tach remained steady so I'm not concerned about it.

Finally if anyone wants to do this the part number for the 4' mower pulley is 69620. Don't forget to measure distance on your existing pulley but I suspect you will need to remove the two washers from underneath as I did.

 

[Brown Dog]

Great news JD855
I did the exact same thing to Befco 110" RFM.

https://www.tractorbynet.com/forums/attachments/314267-befco-c70-110-rfm-fine.html

IF you don't have 18k MINIMUM BTS : your cut is not good.

.

 

[TractorGuy]

Yeah I ran it again today and kicked the engine RPMs up a little over the 540 PTO mark and it cut a lot better. Nothing really wrong with the way this mower cuts for the money anyways but I will always try to improve something if I can. I have searched and it seems like ALL the PTO driven finish mowers are advertising about the same blade RPM. None of them advertise Feet Per Minute like commercial mowers do.

 

[majorwager]

Brown dog,
You are the first other member to acknowledge that he owns a befco C-70. 110 inch. I have no desire to increase blade tip speed, I Have a non- contact tachometer and often reduce engine speed so the pto is turning about 500 rpm. No deficiency in cut result.

 

[TractorGuy]

Brown dog,
You are the first other member to acknowledge that he owns a befco C-70. 110 inch. I have no desire to increase blade tip speed, I Have a non- contact tachometer and often reduce engine speed so the pto is turning about 500 rpm. No deficiency in cut result.

Cut quality depends on grass type as much anything else. I can promise you would see a decline in cut quality if you were cutting bahia at a slower blade speed.

 

[BMan2005]

Cut quality depends on grass type as much anything else. I can promise you would see a decline in cut quality if you were cutting bahia at a slower blade speed.

Agree! I can run 7 mph with my 6' finish mower over our Bermuda, but have to gear down to about 4.5 mph in the Bahia grass to have a clean cut without a random sprig left long and along.

Cool info btw

 

[Brown Dog]

Brown dog,
You are the first other member to acknowledge that he owns a befco C-70. 110 inch ...

I cut with a Land Pride FDR2572" for many years.
I still own a Bush Hog RDTH-84" & both of them has over 18k BTS.
The Befco being under 15k was a Big Disappointment in cut quality.
The bigger pulley mod & another tractor with faster PTO rpm really brought the Big Befco to Life.

Sorry JD855, Not trying to steal your thread.
I'm glad you got your 72" AgMate cutting better

 

[majorwager]

Brown dog,

I also cut W/ a walco douglas 90 inch, not sure of BTS but the cut is excellent. Also used at reduced pto speed, no noticeable difference.

No bahia species in NY, all cool weather grasses.

Happy for improved results realized by OP, but no such modification required here.

 

[Brown Dog]

JDguy,
How much blade overlap does the 72" AgMate have ?

 

[TractorGuy]

JDguy,
How much blade overlap does the 72" AgMate have ?

Good question. I don't know if it has any. I will measure tomorrow if it isn't pouring rain again.