Yamaha PW50, go BLUE.

I had an xr 75 when I was a kid..absolutely indestructable
!!

Here is my nephew at 5 years old . KTM doesn't even make a bike tough enough for this little MX star .

Go with the gas quads.Here are some pics from a couple of weeks ago of my 5 and 8 year old girls tearing up the yard as the snow melted.My oldest has been riding since three.E-ton make the best 40 cc and 50 cc on the market.

Nordic95

Thats what i have, still ride it! (52 MPH GPS )

Or a dirtbike, ride those too.

Hey Jerry i sent ya a PM. Call Dean an tell 'em i sent ya his screen name on here is Wahoo ATV. He's got some nice products.



http://almostfreeatv.com/

I would look at the E-ton 70cc and 90cc quads, we have 4 of them between family and friends. They have a hydraulic disc brake on the rear and a digital rev limiter, automatic trans, etc... check'em out.
We went thru 3 battery trucks before we got these. My boys were 7 and 5 also, I'll post some pics later.

I went the battery powered ride ons for my kids. (Gator and larger Pergo quad) They are ok until you get off the driveway. They get stuck on wet grass and the battery life sux.
Bought this for my 3 & 6 yr olds last Christmas.
http://www.jerseyatv.com/prod01.htm
I can't believe what you get for $400!! Elec. start. Key fob starts and turns ign. off at 50 yrds if they are going too fast and heading for a tree. It's actually a 100cc, and quick. full suspension, headlights and honda clone engine. It has an alarm on it, so no unauthorized rides. It's quiet enough so the neighbors don't mind.

If you live near a Pep Boys auto parts they carry a line of similar gas powered vehicles as those above.

I second the wahoo atv...what are we if we dont support each other...