I changed oil at 50hr with 15w40-t-6. Would rather have used 5w-40 but kubota said not to. Anyways have about 70hr on it. When it’s cold (23f) it ticks/buzzes for a few min. Hard to pinpoint where. Here’s a vid. manual allows for 10w, but also says 15w is fine for this temp. And the word thing the manual says for cold start up is to turn throttle up towards full throttle? Here’s what they say..
Here’s the viscosity recommendation.
50hr service is only the final drive oil. You didn't need to change oil until 500. Did you use CJ-4 oil. Did you change any filters too? When it's cold you might here a little noise. I would only turn idle up a little when its warming up on cold days. Did it do this before you changed the oil under the same temp. Are you up to the full mark? Those do sound different during its regen cycle the tone changes
I’m thinking it probably came with 10w30. I didn’t notice the noise before oil change but really didn’t start it up in these temps. Oil is 15w40 t6, both a cj-4 and ck-4. Changed oil filter of coarse.
I wouldnt worry about it as long as oil is up to too mark and it goes away in a few minutes. Make sure you change final drive oil and save receipts for warrany
Top mark
It is. Not too worried about it, but it would be interesting to understand the mechanics of what exactly causes it to do it. It’s definitely metal tapping. Either a lifter type connection or crank journal in rod bearing. I changed final drive at 50hr. I know the oil is not required to be changed until 500hr but it also states 1 year. I know this machine is at the 1 year mark according to the serial number build date code. Takes these machines take a wile to get here from Japan.
Valve train noise because oil hasn't gotten to the top on the engine yet and or parts haven't warmed up enough to tighten up tolerances.