Whats best kids 4 wheel motorbike

be fair dude-Im betting your students fall into two groups.
Bikers and non bikers.
By bikers I mean people who have even possibly do ride bikes for work or fun.
Bikers have already done the whole brakes at the fingertips,gears down by your left foot,throttle is on the right handlebar bit.
Non bikers have to learn a whole different set of skills.Quite different from driving a car.
So I agree with you that bikers will pick up quad riding faster
but I genuinely feel that a kids first bike ideally should be a little quad.

IF you can find one its around three to four times the price of the LT50 and a truck load harder to onsell once its outgrown.

Mate I couldn't disagree more.
I used to run "have a go" days on an acre or so of wasteland near here.
The issue with starting out on a 2 wheeler is that the kid has to work out a lot of "stuff" all at once.
Balance,brakes,throttle,how to get it to turn etc.
Added to that the simple fact that once going they are totally on their own.
Literally I see it as putting a student pilot in a plane solo after a bit of instruction and saying-go for it.
On a SMALL Quad on the other hand the kid can get a feel for throttle control. bike brakes etc. If they get scared then simply stop or if getting out of control you pull the plug (kill switch) and stop em
Throttle control with young kids (first starting to ride) tends to be non existant-light switch stuff. turn off the switch and a quad stops. turn off the switch on a bike and usually they fall off.
Now I am JUST talking first riding experience here.
Ive seen kids do an hour on an LT and then hop onto a JR50,PW50 etc and pick it straight up.
Equally Ive seen far too many kids faceplant on the peewee dad bought them and not want to go near the bike.
BUT all that said. I do not for a SECOND advocate kids of the age /experience of the young lady concerned being put onto adult sized or even down to LT80 (1/2 the physical size of an adult quad) sized quads.
Its far too easy to go very very badly wrong.

When is quality ever harder to sell ? Plenty in
NZ with money.

2 wheeler way to go ! Chuck them in the deep end like average country
kid.
2 wheeler far safer - 4 wheeler more potential to end up seeing
your kid in a wheelchair or worse.
Always put trainer wheels on two wheeler if you really have
to but then start heading towards 4 wheeler potential danger.

not so, most of the folk I deal with are riding quads every day, some have thousands of hours in the seat. Generally, the ones who also ride two wheelers regularly, have far greater observation and risk management skills, even if they gave never ridden a quad before.

Fairy nuff dude--But I still say get a kid on a quad first before moving on to a two wheeler. GENERALLY Ive found that the most effective way to get them started.

try listing 900922649 KFX50, realy good [gutless] 4stroke quiet 'as', electric & kick start. Neighbours have one & alway wondered why so gutless but had my suspicions so strobed it & at about 5 grand they retard back to tdc pretty much. Stay constant till then & then go straight back to stop them revving. Found a KFX90 4stroke tci box [or battery powered cdi box like original which is also a dc powered box] that stays advanced but revved so hard & went so fast i took it off & put the restricted one on before someone got hurt. Motor parts are cheap on trademe as motor is the most common 50 4stroke type found in seemingly 'all' chinese scooters. Can't remember the type but 'think' GY6 or QUB139 or something. Got a complete top end for about $79 delivered a couple of years ago. Head complete, Cylinder & piston kit, Oil pump, Belt Pulley 'ramp' rollers, Complete Engine Gasket Set etc. Mind you cheap is [for a reason], ended up fitting the original exhaust valve back in after a year as cheapy had burnt out. Checked with a magnet & original was 'non' magnetic & new [burnt] valve was magnetic. Just my thoughts from experience with this model. In saying that i'm sure there's nothing wrong with an LT50 2stroke, will be lighter & can restrict with a washer between exhaust & cylinder & vary the hole size as child gets more confidence. I think a washer on these would work more positively to govern it than relying on the adjustable throttle stop on the thumb throttle. Or do both things as there's no sense in holding it wide open when the exhaust washer is stopping it wanting to rev. Sorry about the essay & hope it makes sense.

one more thing--if you buy one [KXF50 4stroke] make sure it's got good compression on the kick start plus a working electric start & that it starts easy & idles well when warm [as in good compression].

YZ490--did you ever strobe an LTZ50 ? or a DRZ50?
Just wondering if they put the big restricters just on the giveaway kwakkas