95 views and you're prolly wondering why nobody responded with a "great job" reply.
I'll explain.
Sorry to bust your bubble but, Dude, the machine is way too big for that lil boy. It's NOT safe. It's obvious to all except you.
He can barely reach the footpegs and cannot use the shifter and foot brake. NO, adding a hand shifter isn't the answer.
I look at the doughnut part and see how small his hands are and that to reach and use the brake lever is impossible.
Maybe read the ATV Safety Institute guidelines on proper sizing for riders and machines.

I read about a 125cc machine. Suspension is the first upgrade not cc's. The machine is faster than the stock suspension can handle.

PLUS, your "fromt" bumper is unsafe. It protrudes out too far and has sharp edges.

When (not if) your son crashes from not being able to control that machine, I guarantee you that you will feel terrible and wish you had a proper sized machine for him.

You need a nice 50cc DRR or Apex for him. He'll fit it and have loads more fun and in a safer manor.

I also suggest that you remove the video from you tube. Unless you want to continue showing the world your decision to make your son ride a unsafely sized machine.

 

I would suggest u keeping to your self I know it may be a little too big for him i am sorry for not having great deal of money o buy that is a trx90 not a 125cc I put a 110cc in it and put the hand shifter on there for the reason it has fwd n and reverse I widens out the quad out a extra 4 inches he can reach the breaks fine also it has a foot break t just hand breaks also everytime he goes riding I am out there with him you may talk about my fourwheeler build but you saying or implying I am not a good father crosses the line with me I completly rebuilt the suspension also kingpins wheelbearings tire rod ends due o the reason of being unsafe he dose quite well on the quad an ha no issues what so ever

 

Also to add to it I did most of the work with my son to teach him about this if you don't have anything nice to say the leave it to yourself I know alot of single fathers that don't get to do stuff or don't care to do stuff riding is somthing that has made me and my son very close and all you have to say is negative I was just trying to give my son somthing I never got to do at that age thanks guess I should of bought him a Xbox and let him ride on there

 

Actually, I commend you on your desire for your son to ride. I also commend you on the team effort between father and son.
My reply was to the obvious miss sizing of your rider and quad and the dangerous fromt bumper.
Try reading my reply thinking that I'm being safety concious instead of reading it as a all negative reply.
Your 2nd reply re-enforced the fact that I'm right and you just don't like it.

 

Whatever man he has rode that machine and was his first one for 7 months he has had a few incidents on it ran it in deep mud hole and sank it and has ran into a few things and saftey was the first thing on my mind I put him on a lt50 an he litteraly looks like me sitting on his fourwheeler and the only time he rides aggressive is on that track which I built him to teach him the dos and the donts of riding how to lean how to take corners drift do donuts I know when I was a kid my father never let me do this stuff so the first thing I did when I was out I sight and ear shot I rode like crazy and Hurt myself alot in the middle of the woods with no one around I decided if my son wanted to ride I would get him a good bike for him to learn on to grow into the bumper is a temporary addon only and will be cut down to size or replaced with a after market one but it has saved his reared a few times with fences the only thing unsafe right now is the lack of nerf bars which are on order as we speak when we go trail riding my son knows how to respect his machine and dose so accordingly he can reach the brakes just fine on the foot lever with no issue when it comes to saftey I deal with this everyday being offshore I deal with dangorus stuff on a daily basis that people of the normal 9 to 5 job would not understand I will say I respect your comment on your personal opinion but when me and my son built the bike was for saftey ad the hand shifter was only on there cause he could not rally get the shifter down and it did not fit on that motor plus with it being a 3 speed fwd bye and reverse and he accidentally put it in revers while riding I would mess some stuff up the bike is also as wide as my wolverine lower to the ground and is darn near impossible to flip like I said I respect your opinion but I wanted my son with a good Atv and somthing not prone to flipping I have learned the hard way about safety on a Atv and do not want my son to learn it also but in your reply it was nothing but a bash nothing but negative on what you think the only reason I even joined this site was because I recived alot of help while building it reading older post this is the reason why I usually stay in the kid section to help other fathers like me so fathers and kids can enjoy some quality time I'm sorry you think my sons Atv is unsafe and that he is to small he learned how to ride on this Atv ad he will have the Atv for at least another 6 years or so in which It will go under many changes not a bad idea to me for the initial cost of $300 for a wore out 93 trx90