need some advice

Make sure the suspension is sprung for his weight and the speed will come naturally. You can always bore out the 85 and make a supermini out of it, or sell it and get a bigger bike. By the time he gets fast on the 85, he will probably be big enough for a 125.

TrailDigger wrote:

Make sure the suspension is sprung for his weight and the speed will come naturally. You can always bore out the 85 and make a supermini out of it, or sell it and get a bigger bike. By the time he gets fast on the 85, he will probably be big enough for a 125.

That’s the thing. I don’t know if I should spend the money on suspension when he’s to tall for the bike or make it a big wheel with a taller seat or just get him the KX100. I don’t mind spending the money either way because my first priority is to have him on a safe bike. Honestly wish he was tall enough for a 250f and I could just be done with it. Put a flywheel weight in it and let him slowly get used to it. The sag is set at 95mm. But there’s almost no free sag. I know he needs a bigger rear spring. I used racetech chart. I used the same chart for my bike. I just hate to dump money in suspension on a bike that he might get the rest of this year out of

Go with the kx100. If hes already outgrown the 85 its time to move up. Future proof yourself at least a little bit. Regardless of where you go, spend the money on springs.

Dont waste time and money on a 85 or 100....Time for a 125...

ktm-5 wrote:

Dont waste time and money on a 85 or 100....Time for a 125...

x2. KTM has that find your line thing. 100 a month for a 125. You can always put a flywheel weight on it to smooth out the powerband and keep it running as well.

Thank you everyone for all the advice. I really appreciate it

How good is he? Unless he is ripping that 85 and money is not the problem I would do the 100 then the 125! We have sprung a few super minis for 150+ pound kids. If he is pretty good on the 85 and confident the 125 jump will not be bad, but 12 is a little young IMO unless he is above average rider....

I also did the 85 to supermini mod. It's really not worth it unless you just like building bikes like me lol!!

get a 125. He will enjoy it way more. 5'5 125 is time for a 125.

The 100 is still the same frame and ergonomics. Basically the swing arm and rims ar slightly larger so the only difference height wise is when he has his feet on the ground sitting still.

For a 125 5foot 5 is a little short but you could have the suspension shortened and back to normal after he grows a couple inches more.

IMO on the 85 I would look into taller handlebars and getting the suspension done and get ready for a 125 or 250F next year.

2nd the idea of moving him up. Find a clean 125 of any brand and have him start getting familiar with a full size bike. He will be there soon enough. You could mess around with mods or a big wheel and get by for a handful of months...but a big bike is inevitable.

Getting a bike resprung is not all that expensive. All the big money in suspension is usually from having it valves. SR1 is a company near me and what he does is trade the springs out. So if he has a spring that will fit your son he will take your springs in exchange for his. My buddy got his done and I believe it was $85. Cause all you’re paying for is labor cause he is taking your springs in exchange for the heavier ones. I’m in North Carolina. That’s what I would do. Just respring it.

lumpy790 wrote:

The 100 is still the same frame and ergonomics. Basically the swing arm and rims ar slightly larger so the only difference height wise is when he has his feet on the ground sitting still.

For a 125 5foot 5 is a little short but you could have the suspension shortened and back to normal after he grows a couple inches more.

IMO on the 85 I would look into taller handlebars and getting the suspension done and get ready for a 125 or 250F next year.

Actually the KX100 frame is bigger than the Kx85 frame. Its very obvious if you look where the gas tank mounting bolt is. Probably at least 1-2 inches bigger, along with swing arm and wheels.

have gone from a 85 to 112 then to a 125, sell the 85 and go get a 125 shave the seat a little and get an lowering link, he will ride it for 2 years then get a 250f

rsarno wrote:

ok so i bought my son a 2018 kx85 last September because he out grew his 65. over the winter the kid must have grew a foot because he's to big for the 85 now. i have all the clickers turned in and hes still bottoming out. he's 12 years old 5'5 125lbs. My question is should i do a big wheel conversion and get a taller seat or get him a kx100? Is it worth the time and money to do the suspension and all the work on an 85 or just get him the 100? The only thing is he's not using all the motor of the 85 yet, its just hes to big for it. Not sure how much more power the 100 has.He's getting faster and faster but the suspension is holding him back. hes not comfortable landing long jumps but he knows he can make them. just wondering if anyone has run through this. any advice would be greatly appreciated. thank you

"i bought my son a 2018 kx85
Is it worth the time and money to do the suspension and all the work on an 85 or just get him the 100?
he's 12 years old 5'5 125lbs.
he's not using all the motor of the 85 yet,"

Nothing here even remotely suggests he needs a 125 as others have suggested, plus he might have a hard time touching the ground. also, if he is a beginner level rider, a 125 can be a quick way to send him to the hospital.

He will likely never, ever, be able to use all the power any high perf bikle has, if he could, he would be a national champion.

I would buy a used 100.

We are currently getting the suspension done on my 12 yr old (115 lb) 2017 KX 85
It already has the longer swing arm with big wheels. New springs and revalve, I will let you know how it turns out.

I am looking for a KX 100 frame 14 and up, lmk if anyone has one for sale.

Thanks

SBD wrote:

We are currently getting the suspension done on my 12 yr old (115 lb) 2017 KX 85
It already has the longer swing arm with big wheels. New springs and revalve, I will let you know how it turns out.

I am looking for a KX 100 frame 14 and up, lmk if anyone has one for sale.

Thanks

"I am looking for a KX 100 frame 14 and up, lmk if anyone has one for sale."

Not gonna happen.

SBD wrote:

We are currently getting the suspension done on my 12 yr old (115 lb) 2017 KX 85
It already has the longer swing arm with big wheels. New springs and revalve, I will let you know how it turns out.

I am looking for a KX 100 frame 14 and up, lmk if anyone has one for sale.

Thanks

barnett468 wrote:

"I am looking for a KX 100 frame 14 and up, lmk if anyone has one for sale."

Not gonna happen.

Why is in not gonna happen ? Please do tell

SBD wrote:

We are currently getting the suspension done on my 12 yr old (115 lb) 2017 KX 85
It already has the longer swing arm with big wheels. New springs and revalve, I will let you know how it turns out.

I am looking for a KX 100 frame 14 and up, lmk if anyone has one for sale.

Thanks

barnett468 wrote:

"I am looking for a KX 100 frame 14 and up, lmk if anyone has one for sale."

Not gonna happen.

SBD wrote:

Why is in not gonna happen ? Please do tell

i have never seen a kx 100 part out, this does not mean you cant get one.

barnett468 wrote:

"I am looking for a KX 100 frame 14 and up, lmk if anyone has one for sale."

Not gonna happen.

SBD wrote:

Why is in not gonna happen ? Please do tell

brody wrote:

i have never seen a kx 100 part out, this does not mean you cant get one.

I have seen them on Ebay, Can buy a brand new one today for $598 on RM, but would prefer used for price break.

SBD wrote:

Why is in not gonna happen ? Please do tell

brody wrote:

i have never seen a kx 100 part out, this does not mean you cant get one.

SBD wrote:

I have seen them on Ebay, Can buy a brand new one today for $598 on RM, but would prefer used for price break.

isnt the 85 and 100 the same frame?
if some one is parting an 100 i would want to know why, i have bought used frames and turns out they are cracked.
i would say just be careful.\

why not buy an 14 plus 100 and take the motor out of the 85, and part the rest of the 85

brody wrote:

i have never seen a kx 100 part out, this does not mean you cant get one.

SBD wrote:

I have seen them on Ebay, Can buy a brand new one today for $598 on RM, but would prefer used for price break.

brody wrote:

isnt the 85 and 100 the same frame?
if some one is parting an 100 i would want to know why, i have bought used frames and turns out they are cracked.
i would say just be careful.\

why not buy an 14 plus 100 and take the motor out of the 85, and part the rest of the 85

No, the KX 100 frame is a little bigger than the 85.
You can easily tell them apart at the track, just by looking at the gas tank bolt location.

Cracked frame is not a big deal, we can fix that no problem!

SBD wrote:

I have seen them on Ebay, Can buy a brand new one today for $598 on RM, but would prefer used for price break.

brody wrote:

isnt the 85 and 100 the same frame?
if some one is parting an 100 i would want to know why, i have bought used frames and turns out they are cracked.
i would say just be careful.\

why not buy an 14 plus 100 and take the motor out of the 85, and part the rest of the 85

SBD wrote:

No, the KX 100 frame is a little bigger than the 85.
You can easily tell them apart at the track, just by looking at the gas tank bolt location.

Cracked frame is not a big deal, we can fix that no problem!

ok thought the frames were the same, good luck

SBD wrote:

We are currently getting the suspension done on my 12 yr old (115 lb) 2017 KX 85
It already has the longer swing arm with big wheels. New springs and revalve, I will let you know how it turns out.

I am looking for a KX 100 frame 14 and up, lmk if anyone has one for sale.

Thanks

barnett468 wrote:

"I am looking for a KX 100 frame 14 and up, lmk if anyone has one for sale."

Not gonna happen.

SBD wrote:

Why is in not gonna happen ? Please do tell

Because it's like waiting for the winning lottery ticket or sasquatch to arrive. It is simply unrealistic. If you want one that new, you need to buy a new one. There are a few older 100 frames available however.
.