<font color=blue>...Can you tell me if I would in fact risk damage or will the hitch just refuse to lift that much weight???...</font color=blue>
Hi Emery,
I'm not familar with your Kubota, but I'll answer the 3-point hitch as a generic question for all manufacturers.
A Little Background History first…
3-Pt Hitch capacity…
All ag tractors are ASAE S217. spec rated 24" behind the lift arms or link ends in a full transport position... Compacts can be rated also at the "yoke" or "rockshaft" end which will give you a much higher number...{simple law of physics} but the 'real world' is out at the implement end.
Ex. ABC tractor is rated 4800 lbs. @ the rockshaft and 3300 lbs. 24" ASAE rating.- same tractor…two different numbers and two different reference points.
They also do the same thing with loader spec's...
Ex. ABC tractor loader is rated 2325 lbs. @ the pivot pin max ht. and 1705 lbs. @ 500 mm beyond pivot pin max ht. {approx. center of bucket} for ASAE S301.2 spec’s. – again same tractor loader, two different numbers and two different reference points.
{Not to confuse the issue, but take this same loader and put it on 6 different tractors and you’ll come up with 12 different sets of numbers…}
Back to your question…
If your 550 lbs. is rated 24” behind, you should be able to lift the 650 lb. Tiller a few inches off the ground, move the tractor, set the tiller down and start rotor tilling… You may not however be able to lift it fully all the way up to “transport position” and drive down the road with it.
Normally, the relief valve will go off, not allowing you to lift more than the system can safely handle… so no damage would occur… but lifting 650 lbs. on a small compact may make the front end of your tractor very light/lift it up in the air/sloppy control of steering ability/etc…. so you may need some front weight to hold it down and keep the tractor stable.
So, you may want to load up your 3-pt hitch with 650 lbs. of “stuff” and see exactly what the hydraulics will do, and how the tractor will handle/steer/drive before you make the purchase…
Good luck Emery.