I think valve clearance is very important. That being said the Kubota engines don't seem to get out of adjustment much. Maybe you could buy a service manual and learn to do it yourself? It really isn't very hard. Or maybe there is a local mechanic who could check it for you?
I'm assuming that by valve clearance they are talking about the space between the valve stem and the rocker arm? If that is the case, like eserve said, it shouldn't be much of a problem with a set of feeler gauges and a new valve cover gasket.
Joe I want to add one more thought to the recommendations already provided. On cold start up listen for valve chatter ( clacking in the valve cover ) if it grows louder as the tractor warms up you need to check the valve lash. It will do a lot of damage to your valve seats causing hot spots because the wear lash ( out of adjustment from factory specification due to metal to metal wear as the engine breaks in ) will not allow the lift needed to cool the valve face and seat relationship not to mention overlapp needed for peak torque and Horse power output ( mechanical advantage ). Give the old ear a shot at finding this noise and judge it using your God given senses before worring about nothing. It's like Ed said, Kubota's valve trains are superior to other diesel manufacturer specifications.
Now, that's good news! Especially for my financial situation! I do want to do what is "right" by my tractor and I strongly believe in good pm, but the cost of bringing a mechanic to my tractor was going to cost a lot more than the proceedure and I really can't afford that!
Thanks, Ob1kubota, and congratulations on moderator appointment! I do listen to start ups....and the loud clatter is very brief....one to two seconds. As it gets colder, as in below 20F, that's when I plug her in for an hour before starting and I have a "quieter" cold start. It is comforting to know that I need not worry about valve clearance until or unless that clatter persists beyond the brief few seconds at start up!
It's also a big comfort to hear Vic say he hasn't done any "routine" valve clearance adjustments, only in conjunction with another job involving tearing the engine down.
Not trying to ressurect an old subject, but my B7001 has unknown hours on it and was just wondering if this would help. It is a '77 model, and doesn't appear to have ever been serviced on the inside of the engine.
Someone on another thread stated that the engine ran better after adjusting the valves.
Mine runs OK and is only clanky in the valves when cold...
Just wondering if it is worth the trouble.
Kubota M7040 was running a little rough at idle and smoking a bit more than usual, 1600 hours and the valve lash was more than a bit excessive. Valve cover spec and dealer spec was .015mm. Front two cyls were just a little loose, maybe 018 or so, but the rears were super sloppy, 025 or better. The 7040 needs a bit of digging, remove power steering gear, air intake tube, cover intake with coffee cup remove muffler, and big bracket over the valve cover, clean everything again then remove glow plugs, injector lines and valve cover.