past ck20 hst problems?

Bob_Skurka · Jan 4, 2006

The only gear tractors I will ever buy again are antiques that I will buy to restore. HST is a much better system to use when finish mower or for doing FEL work. It offers advantages wherever there are speed or direction changes and you are powering PTO equipment. Gear is clearly better for ground engaging work like plowing because it more efficiently uses power where HST wastes a bit of power, but if you have enough HP to begin with then I will take HST every day of the week except for Sunday when I drive an old Oliver down mainstreet just to wave at the folks and see them smile when they see the old iron.

Highbeam · Jan 4, 2006

"Your left foot is sad, lonely and feels left out because it has nothing to do."

Except for the occasional emergency pushing the clutch.

You might also be disappointed to note that the brakes are on the right side so you can no longer steer with the brakes unless you are crazy enough to engage cruise control and whip around corners at full speed.

You really have to try one to see. Easily inch the tractor forward or back by placing your hand on the go pedal to assist in lining up 3ph implements. The HST is like a deadman switch in that as soon as you lift your foot from the go pedal the tranny stops supplying power to the wheels and actually acts to slow the tractor down.

mathey · Jan 4, 2006

( You might also be disappointed to note that the brakes are on the right side so you can no longer steer with the brakes unless you are crazy enough to engage cruise control and whip around corners at full speed.
)

I don't think I'll ever figure out what they were thinking with this design... /forums/images/graemlins/confused.gif

stanc · Jan 5, 2006

Climbing over a 2X4 from a stall depends on the touque that the tractor can supply. Take a scale attached to the front of the tractor, in neutral, and measure how much pull force is needed to get the tractor over 2X4. Measure the radius on the rear tire, multiply by the force = torque needed to get over 2X4.

The HST in the CK20 has a rated torque = max engine torque. Note that an automatic transmission can multiply torque up to X2 (torque converter).
The only torque multiplying on the CK20 HST is though the gear reduction. HST High range torque is equivalent to the standard CK20 is high range, 2nd gear( approx, if I remember correctly). A standard CK20 in High, 2nd, would probably have difficulty getting over the 2X4 from a stall, and tough on the clutch.

I quess that a HST with more rated torque could be a solution (torque multiply), but adds expense, and takes more engine power just to operate the HST.

In the past, some HSTs relief valves were blowing off to early, not delivering rated torque.

Anyway, just my $0.02, data from my 2003 CK20 workshop manual.

Bob_Skurka · Jan 5, 2006

(

In the past, some HSTs relief valves were blowing off to early, not delivering rated torque.
)

I don't know about that point, but I do know that Getut's relief valve was within factory specs when it would not go over the 2x4.

HODAK · Jan 5, 2006

My .02 - The brakes on the right side don't bother me. Most of the time my foot only goes "out there" to set the parking brake and then release it. My old tractor brakes were on the same side, so it still is somewhat second nature. Like HIGHBEAM said, "the left foot is lonely". /forums/images/graemlins/cool.gif

RedRocker · Jan 5, 2006

( I am confused about the suggestion that you get more torque with a HST by backing off on the "accelerator" pedal. Most diesel engines have a pretty flat torque curve. How should backing off on the "gas" end up giving you more power when climbing a hill etc. Seems counterintuitive to me. )

You can't think of the HST pedal as a "gas" pedal, your gas is on the steering column, you don't move it. The pedal applies the torque as well as acceleration. It is counterintuitive, but if you have the pedal to the floor you'll get more torque by backing off of it.

KiotiJohn · Jan 9, 2006

( I don't know about that point, but I do know that Getut's relief valve was within factory specs when it would not go over the 2x4. )
In all reality, the valve did "test" at specs, but it was replaced with a valve that hit relief at a little higher pressure than the original.
There was a problem with some of the valves springs sticking which didn't always get detected in the standard testing, but manifested during real working situations. That was the case in getut's situation.
I was involved in this case and discussed it at length with one of Kioti's engineering managers. As far as I know, the offending valves are all gone, and there weren't many of them to begin with.
Kioti service sent one of their own techs to getut's house to check and repair the problem.
John