Advice needed. How to restrict bike?

**glukasil** · 27th July 2012, 21:25

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** · 27th July 2012, 21:33

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

**cheese** · 27th July 2012, 21:49

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

**Akzle** · 27th July 2012, 22:37

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** · 27th July 2012, 22:40

Originally Posted by 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...

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** · 28th July 2012, 00:02

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** · 28th July 2012, 07:49

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** · 28th July 2012, 11:46

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** · 28th July 2012, 11:57

Originally Posted by 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...

+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** · 28th July 2012, 12:20

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** · 28th July 2012, 17:25

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** · 28th July 2012, 18:38

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** · 28th July 2012, 19:26

Originally Posted by glukasil

hi guys. i need an advise.

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

**White trash** · 28th July 2012, 20:13

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.