Hydrostat surges jerky in low range

[Kent R]

I purchased a new KIOTI ck20s in May 2013. I like the tractor over all but the hydro is very jerky especially in low range. It is noticeable mostly on level ground. If I try to ease it like parking in the barn it tends to jerk then surge forward. It is not smooth. When under load it does not do this. Rpm's do not make a difference. Dealer says it will wear in and smooth out. I have 50 hours on it now and am curious if any one else has the same problem.

 

[Leejohn]

Were you going change hyd oil and filter at the 50 hr. service?

 

[rider7767]

According to the troubleshooting tree it says:
"Tractor jerks when traveling slowly."
"Inspect neutral valve"

It is a place for your dealer to start.


2.3.5 NEUTRAL VALVE
Neutral valve is a valve that secures neutral position during starting. When the swash plate’s angle and discharge volume become smaller, the motor does not rotate because the oil flows into the inner passage of case (passage B-drain circuit) via orifice. (Maintaining neutral width) As the swash plate’s angle increases, the oil volume passing the orifice also increases causing high pressure drops in fore and aft of the orifice. According to pressure differences generated at this moment, the oil pressure overrides spring force, then the valve moves toward left by blocking contacts between passages A and B. Accordingly, the discharged oil from the pump that was flowing toward the drain circuit (passage B) flows into motor causing its rotation

 

[k0ua]

I can tell you this much, it is not normal. I have owned 3 hydro tractors, 3 different brands, including my present machine a Kioti, and all were smooth as glass at any speed.

James K0UA

 

[rider7767]

I can tell you this much, it is not normal. I have owned 3 hydro tractors, 3 different brands, including my present machine a Kioti, and all were smooth as glass at any speed.

James K0UA

I agree; I test drove a CK20S HST before I decided on the gear model. It was smooth as silk.

 

[Gil Case]

Keep the RPM's at 2100 or above for best performance of HST, or so I am told by dealer.

 

[k0ua]

Dealer says it will wear in and smooth out. I have 50 hours on it now and am curious if any one else has the same problem.

I have a dollar in my pocket that says if you go back to that dealer and drive a different CK20 on the lot, I bet that it does not jerk. Your tractor is defective and needs to be serviced.

James K0UA

 

[Fuggley]

hummm....wondering if your hydro fluid is low?
I have a CK30H that always gives a few good jerks when first starting off in either forward or reverse and I can't seem to get a good reading on the hydro dipstick. When first pull the stick, there is no fluid on it but when I put it back in and haul it out again it shows max full. Think I need to dump more fluid in it... maybe it will smooth out the drive?

 

[oldnslo]

Kent R,
Are talking about transitioning from sitting still to moving? If yes I would suspect the neutral valve also. My Branson also does this in high range when cold. In low range it is smooth. I have 100 hrs on mine with little or no change in how the HST operates.

 

[GMtb42]

Like others my CK20HST is smooth too, no jerking. Take it back to dealer something is wrong.

 

[VictorW]

My CK30hst has been smooth since I got it with 2.4 hours. The only time it acts I guess sluggish but not jerky is when I first start it with temps below 30'F. After a few minutes for it to warm up, it moves fine. The 2000rpm advise is so the hst is getting the proper precharge but that is for it to work at 100%. It should still be able to move at 1000rpms and be smooth.

 

[mj007]

Like others my CK20HST is smooth too, no jerking. Take it back to dealer something is wrong.

Mine has been the same (241 hrs.)

 

[Coyote machine]

Mine has been the same (241 hrs.)

Smooth or jerky?

 

[Coyote machine]

I purchased a new KIOTI ck20s in May 2013. I like the tractor over all but the hydro is very jerky especially in low range. It is noticeable mostly on level ground. If I try to ease it like parking in the barn it tends to jerk then surge forward. It is not smooth. When under load it does not do this. Rpm's do not make a difference. Dealer says it will wear in and smooth out. I have 50 hours on it now and am curious if any one else has the same problem.

It's NOT right. Call your dealer and ask him to fix it NOW. When does he say it will 'smooth out? 61.5 hours? 324 hours? Ridiculous!:confused3:

 

[timbatrader]

At work we have had hydrostatic forklifts for the last thirty odd years (Linde’s made in Germany) over the years we have had problems with them being jerky it has always ended up being a blocked oil filter on occasions mechanics have assured me they have changed all the hydraulic filters and it has not cured the problem and gone looking in other areas valves etc. On both occasions they had missed changing a filter hidden out of sight inside the hydraulic tank once that was changed the problem went away

 

[mpham]

When I first start mine up and try to sneak it out of the garage it will jerk quite a bit. Once I drive it a while and it warms up it is smooth as silk.

 

[shelby12]

My ck20hst does it too. Dealer replaced tractor. New one does it too. I will ask him about neutral valve. If you find anything out let me know.