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  1. #1
    Gold Member
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    '07 KuBoTa B7800 and Jinma 254

    Default Jinma 254 Clutch is Harsh...

    By harsh I mean that even though adjusted to the specified clearances and pedal free play the clutch has a sudden nearly violent engagment at the top of the pedal travel.

    This is making fine manuevering in close quarters difficult. I am parking both tractors inside my smaller barn - once a horse stall for four horses with a tack area but with the stalls and feeders and all dismantled and set aside leaving a space about the size of an older two car garage. It should be enough room but the Jinma clutch makes not hitting a wall or the kubota a touchy thing.

    Even at idle the tractor jumps forward or back once the clutch engages - there's no way to finesse it by slipping.

    Anyone have experience of this and know a solution?

  2. #2
    Bronze Member
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    North Alabama, USA
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    Farm Pro 2425

    Default Re: Jinma 254 Clutch is Harsh...

    Do you have the creeper gear box? I can't imagine you would need a slower speed than LL1.

  3. #3
    Gold Member
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    '07 KuBoTa B7800 and Jinma 254

    Default Re: Jinma 254 Clutch is Harsh...

    Quote Originally Posted by CSH
    Do you have the creeper gear box? I can't imagine you would need a slower speed than LL1.
    Yeah, it has the creeper but it's not in play here. I tried it out but leave it in it's High range.

    There's enough torque to start off in any gear but using a different gear that way has no effect on how the clutch engages.

  4. #4
    Super Member greg_g's Avatar
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    JD3720 Cab, 300X loader with 4-in-1 bucket

    Default Re: Jinma 254 Clutch is Harsh...

    There are more clutch adjustments than just pedal play. Have you referred to the clutch adjustment section of your owner's manual yet?

    //greg//
    USN (Ret)
    Former Chinese tractor owner (x4)
    Current John Deere owner

  5. #5
    Elite Member RonMar's Avatar
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    Jinma 284 delivered 06/28/05

    Default Re: Jinma 254 Clutch is Harsh...

    What Greg said. There is some good information IRT clutches on Tractor Outlet's 3 pages of online service bulletins, with clutch info on page 3 Jinma Service Bulletin 3

    Johns Jinma website also has some excellent resources. JMClutchAdj

    This clutch does not use the traditional coil springs to apply pressure to the plate. Instead, they use a compressed cone shaped washer type spring, part # 4 in this link. http://www.johnstractor.homestead.co...DualClutch.jpg

    This type spring has a very narrow operating region so this clutch has a very small range of movement which makes adjustments more critical between main and PTO clutch and throw-out bearing/control linkages.
    Ron

  6. #6
    Gold Member
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    '07 KuBoTa B7800 and Jinma 254

    Default Re: Jinma 254 Clutch is Harsh...

    Yeah, a Bellville spring, or at least sometimes called that.

    Yes, I've checked through the adjustment procedure that was included in the user/maintenance manual as accurately as the translation allows and the clearances seemed correct per that volume.

    I've not seen the bulletin you've posted Ron, so I'll see if it might offer a clue to relieve this problem.

    I think I did notice something about the clutch when whizzing through John's site, so I'll revisit.

    This is a drivability issue only - the clutch works and holds very well. It is apparently adjusted within the parameters of the manual I have so I'm only looking for something short of holding my foot on the pedal to 'burn in' the disc(s).

    It may just soften up with use. I once bought a new Subaru that had a clutch that felt a lot like this. There was nothing much to do about it except get used to it, which I did within a thousand miles or so.

    edit: the process described in John's by a fellow named Mark is pretty much what I did (I wasn't ABOUT to split the tractor over this!) but using my best reading of the manual for measurements. Mark's work offers some hints that are beyond the manual so as soon as I can I'll get back in there.

    I just thought that maybe someone else had experienced a similar new clutch and had found a way to make it less sudden.
    Last edited by hill; 10-11-2007 at 11:15 AM.

  7. #7
    Elite Member SPIKER's Avatar
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    Ohio, Jeromesville, Ashland County
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    Jinma 284

    Default Re: Jinma 254 Clutch is Harsh...

    Hi Hill

    I'm Mark from Johns site, and recently was back into mine, to attempt a re-adjust for similar problem as you are having, mine is like you stated holding (for now) with little or no feel left in it.l I have close to 400 hrs and have only used perhaps 20% of the usable clutch material (80% left) but there is no adjustment left in there on mine. I'm wondering if there may have been a breakage of my spring washer as it seemed to happen overnight. This time I didn't get pics as I was in a hurry but have a better camera now too anyhow I'm hoping to get mine though winter & keeping it going until my concrete gets done. (wanted it done this summer )

    how many hrs and perhaps I can get you better info on HOW to better adjust the clutch. remember adjusting the MAIN clutch will mean the PTO also will need some fine tuning as the pto is engaged off from the main plate using the bolts and lock nuts as a means of changing the distance the two clutches are IN at and pedal free play between PTO and MAIN engagement's.

    mark M
    I may remember why I went to the other end of the shop, I'm just afraid once I get there I'll forget how to get back!

  8. #8
    Gold Member
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    '07 KuBoTa B7800 and Jinma 254

    Default Re: Jinma 254 Clutch is Harsh...

    Hi Mark,

    This one is new with just 5 hours, and the issue arises out of my preservice activity. The tractor was assembled when I received it, bought at auction, but I don't think it was assembled by anyone too familiar with the practices worked out by you and others in the effort to assure a long and happy life for the tractors. for example both bolts that hold the wheel hub to the brake backing plate and go outward from center were loose, one of them showing at least 1/4" of thread. The gauges were intermittent because of crossed connections at the oil pressure sender (of all things) and the main battery ground having been left loose. There were several other minor things, and I'd imagine that there are more as yet not discovered.

    As said, this is a drivability problem, a "grabby" clutch. Maybe it's only it's newness that causes this? It's a type of thing that I am hoping will get better with use.

  9. #9
    Elite Member RonMar's Avatar
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    Jinma 284 delivered 06/28/05

    Default Re: Jinma 254 Clutch is Harsh...

    Well with only 5 hours on the clock, the mating surfaces on the clutch face and pressure plate may still be rough. Heck, there could even be corrosion in there as this thing may have set for a while. The clutch is setup at the factory, and unless a very thurough service was done by the assembler, it was most likley not even looked at. Based on the number of asembly gripes you have found, I would say it was not examined. I would definitely check the plate relationships and make sure the throwout bearing is separating from the fingers, but put a few more hours on it also to see if it smooths out. You may also find the brakes are the same way. My clutch was allright when new, and got smoother with use. the brakes being used less, took longer to loose their "grab"
    Ron

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