Advice needed. How to restrict bike?

[glukasil]

hi guys. i need an advise. just got a quad for my 8 year old boy.
it is lem frame and 50 cc 2 stroke ktm engine. it is fast , too fast for the boy as he never ridden anything but my back :)

what is easiest way to restrict top speed?

any reasonable advise would be appreciated

thanx a lot.

[Subike]

loosen the throttle cable so that he cannot get full throttle.

[cheese]

Normally there is a screw on the throttle that stops them turning it all the way.

[Akzle]

8 years old i'd say he's big enough to handle it. let him scare himself a bit and learn how real life works...

[Subike]

8 years old i'd say he's big enough to handle it. let him scare himself a bit and learn how real life works...

agree with you here, At 8 I was riding motor bikes myself, and enjoying it. A Puch 50cc
But the O P wanted to know how to restrict the bike his son rides.
And as a parent, maybe he knows how far his son can go right now, better than we do

[neels]

Simple way is throttle movement, although this doesn't always work as if it has auto clutch then enough throttle for the clutch to engage can be too much for the younguns.

The other standard way is with a restrictor plate between the carb and intake, may have the same problems with the clutch although less likely as the restricted airflow would probably have more effect at higher engine speeds.

[driftn]

It will only go as fast as the throttle is turned. * is old enough to understand that "if you turn this hard its going to take off". What im trying to say is let em go mate, only going to get scared once.

[barty5]

depending on the motor in it from what ive read you can get restrictor kit you can also addjust the clutch so they dont take off so harsh google the motor specs

[SMOKEU]

8 years old i'd say he's big enough to handle it. let him scare himself a bit and learn how real life works...

+1 to that. He may scare the shit out of himself once or twice, then he will learn to be sensible. Make sure he's wearing good gear, and to be honest, a 50cc engine isn't going to pull a massive wheelie and spit him off the back.

[barty5]

you had a go on some of those small ktm im 5'11 was 87kg bulit a ktm sx85 with a near bald tyre in the wet could hardly keepthe front end on the ground in 4th an 5th they build them to the limits of what you can get out of them. no harm in taking a little caution.

[schrodingers cat]

Geting a fright is all well and good but I'm not sure if riding full tit into a wall or a car or a wire fench improves the lesson

A friend of mine used the electronics from an old garage door opener so he could kill the ignition remotely as an aid when he was first letting his kids loose.

[scott411]

i think the clutch set up can be adjusted on teh earlier KTM motors, and it makes a hell of a lot of difference to acceleration,

the other way to restrict it is to run a thinker head gasket,

[Hitcher]

hi guys. i need an advise.

No, you need advice. Starting sentences with capital letters would improve the readability of your posts.

[White trash]

Everybody saying "Let him go, he'll learn" obviously has no idea what a KTM 50 SX motor is designed to run like. A kid who's never ridden before would quite likely run away and hide just hearing it being warmed up. They're pretty feral.

You can add a spacer to the top of the carb slide to not allow it to get to full throttle but if the kids light, the thing will still fricken fly. I'd be inclined to adjust the clutch for real early pickup, not a lot of torque at low revs in these motors. Possibly chuck a restrictor washer in the header pipe too.

[gwynfryn]

Why not re-power with a four stroke they're perfect for an eight year old. You can also bond in the workshop in the evenings while you rebuild it.

[glukasil]

thanx guys , have not expected much of reply....
rode the quad myself today :) it is not that fast to pick up but powerband hits hard later.

will need restricted for top speed only....
is it difficult to adjust clutch so it picks up a little faster?

thanx for understanding my situation....he is my kinda step son and his mum rises him soft.

[Akzle]

No, you need advice. Starting sentences with capital letters would improve the readability of your posts.

no it wouldnt

:P

[CRF119]

You could try a remote kill system so if you think he is getting out of control you can just push a button. To do this you would need a small 12v battery and a cheap alarm system which triggers a normally closed relay to open and kill the circuit. The problem with bikes is when the kid twists the throttle and it goes he is left swinging of the bars twisting more throttle which ive seen many times ends up going bad. Even seen adults do it.

If you want to restrict throttle travel the best option is to insert a spacer above the carb slide to stop it being lifted so high. This will be much better than making the cable all lose and sloppy. As he gets better you can put smaller spacers in to restrict less throttle movement within the carb slide. Quick image below to explain if this didn't make sense.

[CRF119]

Also do the little KTM engines run power valve system? If you disconnect that it will decrease the power up top.