Jinma 254 PTO speed vs RPM

[254OZ]

Yes, the wheels have been set to their widest stance by flipping the inner discs of the rear wheels. I highly recommend doing this as it dramatically improves the stability. I also swapped the wheel weights to the other side of the inner discs so they still end up on the outside of the wheels. I painted the weights as what was the inner unpainted side is now outwards.
Some people swap the front wheels over to get a wider stance on the front too but I reckon that is a big mistake as there is evidence it leads to front hub breakage and because the front axle has a central swivel point it doesn't really improve stability much anyway.
This is what the wheels look like after the change


I have about 225 hours on this tractor now and from what I have read (from the more cluey owners anyway) there is no reason why it shouldn't go on for many years as long as all the maintenance is done properly. I'm very happy with it anyway. I wouldn't buy one for commercial use but for a hobby farm and someone who doesn't mind doing their own maintenance it's a lot of tractor for very little money compared to the competition.

The photo in my previous post also shows part of my CAD designed, homemade backhoe sub-frame... but that is another (long!) story.

 

[mickstanz]

I'll have to look into widening the rear wheels after harvest. My first thought is that it's going to put more stress on the rear wheel bearings, but everythings a trade-off.

I got mine with 125 hours on the clock, an older guy owned it since new and used it to take hay to his horses down the back paddock and drilled half a dozen holes. All the paint etc was still on the bucket it was like brand new. Before I did anything with it, replaced every fluid with quality stuff, threw the Chinese filters out and replaced with Baldwin filters, but by far the most important thing I did was reset the valve clearances and re-torque the head bolts. Should have been done at 50-100 hours but better late then never. A bit scary how far out a couple of them were.

I'v only done 30 hours since I got it but so far so good. I agree, if you look after them they should last for a fair while.

A homemade backhoe is a big project to take on, would it need its own hydraulic pump, PTO driven?

I'm in the process of designing a 5m spray boom. It will basically be a 150l tank, electric pump, skid mounted so can be mounted to/removed from the carry-all, wings will fold in and be able to be turned off so can spray using just the tractor width, with a hose/hand wand for spot spraying. Before farming I was a draughtsman/designer but my AutoCAD skills are average now, I just use SketchUp from Google. Obviously it's not as sophisticated as AutoCAD but it does a bloody good job.

 

[254OZ]

Sounds like you got a good buy there and that you're doing all the right things to look after it.
Is the tractor stored under cover? I reckon that's really important as the dubious quality of some Chinese rubber components means that the overall weather proofing is perhaps not quite as good as you might be used to with some more expensive tractors.
Another thing that is well worth doing to improve the machine's longevity is a proper full clutch adjustment as these are often a bit out from the factory (it will probably need doing by now anyway). It's not a particularly quick or easy job as there are six individual fingers to adjust through quite a small access hole in the bell housing but it's important to get it right to get the maximum life out of the clutch.

I didn't design a whole backhoe, just a sub-frame to rigidly mount what used to be a three point mounted Chinese backhoe. There are quite a few horror stories around about three point mounted backhoes causing tractors to break in half, (usually in the area of the clutch bell housing) so a proper sub-frame seemed like a worthwhile project.
I'm a 3D AutoCad guy so that's what I used but I agree, SketchUp is great and quite capable of doing a perfectly adequate job for this sort of thing. In fact AutoCad seems to be quite rapidly dying out in most industries these days in favour of programs like Solidworks but I can't be bothered (or more likely I'm just getting too old) to learn all the latest software as AutoCad does everything I need.

 

[mickstanz]

Yeah it's always parked in the shed if it's not being used. Last owner must have done the same.

Good call on the clutch, I hadn't thought about checking it as it feels alright but your right it would be worth looking at. I had a quick search and seems there's a few threads round already on how to do this.

I guess we're lucky enough out here that when a job calls for a back hoe we can borrow the big toys from our neighbours.

 

[254OZ]

There's another thing that's important for the longevity of these engines that is often overlooked as it isn't really mentioned in the iffy documentation. You said you changed all the fluids but did you change the injector pump oil?
It should be changed at the same time as the engine oil and uses the same oil type as the engine. The oil doesn't really get dirty but it does get thinned out by high pressure diesel internally leaking in to the oil reservoir. It only takes about 200 or 300ml and is easy to change. There are two drain plugs, a filler plug on top and a level pipe on the front which should have a sort of rubber sleeve plug/cap pushed over it. Can do you some pics if you need them.

 

[mickstanz]

Yeah mate got that oil as well, cheers. I did wonder how often to do it, I think the engine is 100 hrs so you reakon the same time eh?

 

[254OZ]

Yes, 100 hours seems to be generally reckoned to be enough. I suppose it really depends though on how much and what the tractor is used for. I know some people change the engine oil at 50 hour intervals but that seems a bit of an overkill to me.
I always try to avoid running any engine for short periods. If it gets started to do a quick job then I reckon its better to let it warm right up before shutting it down.