Tbh I cant see how changing your oil more often can have a bad effect on your engine life.
Simply put. Your engine creates friction with all the bits going up and down and round and round.
This causes microscopic bits of metal flakes to drift about in your oil and this becomes an abrasive causing
even more friction, leadin to even faster wear... An engine change significantly reduces this abrasive effect.
One thing that can lead to faster engine wear is over/under filling. OR NOT FILLING AT ALL
Over filling causes exsessive crankcase presure. Im not sure of the effects of this, but is a well known fact that
over filling is AS bad as under filling.
Under filling leads to exsessive wear, higher engine temp and finally engine damage.
The correct way of filling a Zoomer, "and I'm not saying you done this wrong ofc, just as a reference", is when filling
up the oil level, the level is checked by only holding the dipstick to the crankcase WITHOUT screwing it in at all.
Level can then be anyware between the top and bottom marks of the stick.
The 600 mile change wont harm your engine, but the maual does suggest a change at round 2000 miles.

This ain't an issue about oil change.
I've always changed my oil @ 1st change 300/450miles
then 1000/1750 etc.
I've had no issues.(5bikes)
Engines love clean fresh oil and correctly filled and maintained
they'll last just fine.

There are several factors that effect the performance of your scooter, loss of compression, spark fuel or air or impropper mixter in 2 cycle engine. I have read the earlier posts and no one has mentioned your carburator, or reed valve, the reed valve is what controls the amount of fuel going into the intake manifold(opens and closes when the piston goes up and down based on crancase pressure...if this is damaged or not functioning properly it could cause loss of power issues. My guess it is a accelorator pump issue, (dirt in needle valve or jet). First - easiest and cheapest is if you have a fuel bowl drain screw open it, and let gass run out till clear and steady stream. check plug for propper gap, check/ replace fuel filter (may not be getting or allowing propper amout of fuel to flow to carb.) the fack you had a water issue make me suggest you drain your tank and start with fresh gas and use premium gas 93 octane or more(the smal carbs do not like the ethinol in fuel). at 1200 miles I do not see your roller weights as an issue although you scooter mayt have a restricter washer located on the cranck shaft beteen the variator and the pulley faceplate, removing this washer will give you about 4-6 mph faster top speed (washer is about 1mm thick - prevents variator from allowing belt to go higher on pully) check your air box filter if applicable.
If you checked all the basic things - next and cheapest is the reed valve (about 20 bucks) then the carburater (about 45 bucks) you will need a reed valve gasket also. (personally I dislike 2 cycle motors - have more that can go wrong and less overall power) If any questions or where to find parts in your area feel free to send an email scooterboys@charter.net advice is free and will always be. good luck ...(you may also check carb jets for forign matter blocking or restricting fuel flow - I do not belive your CDI (spark plug timer/initiator) due to the age and milage of your engine I have a 50cc 2-stroke 1PE40QMB Minarelli based engine with the same issue in my shop at this time - it has 15,752 miles on the odometer (history not know second owner does not have maintnace history) I have ordered a reed valve, and will be replacing the carburator, reed valve, roller weights and belt on this unit to get it road worthy once again (aproximately 90 bucks in parts.) <---customer cost.

Is it possible that your fuel injector is clogged .
I see no gas filter on Zoomer but still looking.

Forgot to mention my biggest suspicion of your lack of power at full trottle or WOT - I would almost bet money your have a hole or tear in your accelerator pump diaphram - as far as I know you can not buy this part indavidually unfortunately you will have to purchase an entire carburator, but you will be anble to inspect the diaphram rather easily. good luck

Thanks for youe input fuzzy, but there is no reason to mention a Carb ,Reed valve, needles, jets or restrictor washers since a Honda Zoomer doesnt have any of these things... Its a fuel injected, four stroke, liquid cooled, 50cc with an electronically monitired ignition system.

Im sorry to say, but I disagree with your statement of 2 stokes having more that can go wrong on them. They dont have remotely as many moving parts as a four stroke. ie: Tentioner, timing chain, rocker arms, valves, etc etc etc...
2-t's are way faster that 4-t since they can rev 3 times higher than 4-t's
4-'s are more durable since they rev lower. It is a simple fact: less revs, less fricktion less wear, longer life....

I have a very similar setup and same issue in heavy rain. The issue seems to be air-filter getting splashed. I have a K&N cone air-filter.

Are there any air-filters that would handle rain..the Venture II from Doppler looks pretty cool - not sure if it can handle heavy downpour? http://www.sip-scootershop.com/en/produ ... +_dp459370

if you want to stop it getting wet just fab up a cover out of a plastic bottle and some cable ties, for a while i used a k&n style inside a foam so the foam would soak the water not the paper.

i drove through a flooded road water up to my shins and no probs, scary as fudge but interesting!

i had issues in the wet or damp at full throttle.i just put the stock airbox back on with some rubber spacers to clear my fat shock and problems solved.didnt see any performance gains with a open filter anyway.just made a good throaty racket.but with the stock box runs fine.went out yesterday in the torrent and it ran like a stocker.no bogging