Colin, it's surprising that your wheels are still rolling with bearings that have 60K km behind them, especially given the many water crossings you must have done.
Like AlexUK suggested, you should replace more than your wheel bearings. The steering head and swing arm & suspension linkage bearings should be replaced too, as they can't have much life left in them after this distance, especially if you consider the fact that these bearings are mounted in the factory with hardly any grease in them. And to make matters worse, the little grease that bearings receive during assembly of bikes at the factory is ordinary white lithium grease, which is useless on dirt bikes that are regularly ridden through water.
Don't be fooled by the labels on the containers that state that lithium grease is water-resistant. Essentially it can't resist water since lithium grease is a lithium stearate made with lithium hydroxide monohydrate (LiOH.H2O) which is chemically hygroscopic by nature. Lithium, or rather LiOH.H2O, is used as a grease additive because of its chemical/physical properties as the softest metal around. For those of us who still remember their chemistry lessons in high school, Lithium is the third element in the Periodic Table (Mendeljev) and is the least dense solid and lightest, softest (alkaline) metal.
If you want to substantially increase the life span of bearings on a (dirt) bike, than you should apply silicon grease or aluminum oxide grease which are both far more stable under hard conditions and much less hygroscopic. I never use lithium grease when repacking bearings, as it gums up too soon. Because of its hygroscopic nature, any water that enters the bearings displaces the oil/lubricant and the remaining dry gum has little or no lubricating properties and will thus result in friction-induced binding of metals.
Most stores that sell lubricants, bearings and/or autoparts in CNX only stock general purpose lithium grease and, based on my experience, have never even heard of silicone grease. Anyway, since you're taking your bike to the Kawasaki dealer for this service, it's no use recommending silicone grease, as they won't have/use it.
Apart from the usual consumables (air & oil filters, spark plug, valve clearance/shims, engine oil, chain & sprockets), other items up for replacement or maintenance:
- fork oil
- fork seals
- brake fluid
- brake pads
- cleaning the pistons in the brake calipers (to avoid premature wear of the new brake pads when the pistons can't retract fully because of rust/dirt)
Engine:
- clutch friction plates
- cam shaft / timing chain
- cam shaft chain tensioner guide/slide
The cam shaft chain replacement is often overlooked, but it's an inexpensive item that should be replaced around 30K~35K km for thumpers, especially when most of the riding consists of 'frequently varying RPM speeds' such as experienced when riding trails, mountain roads, and city traffic, as opposed to more constant RPM speeds when riding on the straight 'open roads'. With frequently varying RPM speeds, the timing chain incurs a lot more 'jerking' action in a single cylinder engine, similar to the 'whipping' effect that acceleration/braking has on the transmission/drive chain.
If you have a new drive chain mounted, check the slack before leaving the dealer. I have bought 3 new bikes at the Kawasaki dealer in CNX over the past few years, and each time they were delivered to me with a chain that was as tight as a guitar string. Luckily I checked and noticed it before riding off, as it might easily have resulted in a damaged shaft or gearbox exit bearing. Based on my first-hand experience, Caveat Emptor is definitely applicable when dealing with the CNX Kawasaki dealer.
I don't know if you intend to hang around at the dealer during the service (I know I would if it was my bike), but if you do, please let us know what you find when the mechanics are 'baring' the bearings.
