Dirtbike moves by itself!!!

[Whitefox]

Hey,

I recently bought a 2002 YZ250 F yamaha dirtbike, all was good until i notices a couple of problems. Firstly when the bike has been put into first gear and the clutch is let out the bike moves forward and continues to move without the use of the throttle!!!! (I can ride it around the backyard without even touching the throttle)

i was just wondering how to fix this,??? I have tried adjusting the idle to different settings but the problem doesn't change. (it gets a bit scarey when the bike moves without you wanting it to)

Secondly when riding along and the throttle is given a quick hard blip the engine splutters and sometimes cuts out. This only happens with quick acceleration with the trottle. I recon that the engine just isn't getting enough fuel. However my main concern is the first problem.



Thanks heaps,

[Grieby54]

The first issue is probably your idle. Try turning it down to where the bike is just barely running, then crank it up just a touch more.

The sputtering problem is your jetting. You'll have to talk to a two stroke guru about that one.

[Whitefox]

Thanks for the reply, I went down and tried adjusting the idle to where the engine was barely going. I then put the bike into gear and then let out the clutch using no throttle and it still went? (shouldn't it stall?) i then rode the bike around the backyard without using the throttle and the bike would continue to move. (The bike putts around not at a heaps fast pase, but enough to keep it moving with me on it)

I tried a number of different ideas like a slow idle and a fast idle but all result the same.

I was just wondering cause i'm new to yz250f's, is it normal for this to happen? I don't believe it is because it would be heaps scarey riding into a corner and using the brakes only to find the bike doesn't want to slow....

[D3luxe]

I'm having the same problem with my RM125. Hopefully someone here can shed some light on this.

[Synyster06Gates]

Do you have a Y250F or a YZ250? Is your bike two or four stroke?

[rossim22]

The first issue is your clutch cable. You need to adjust it. It's catching very very soon, before you even pull the lever. I had the same problem on my car at the drag strip. I'd start creeping with the pedal all the way in.

[MotoMan]

Ok....clarify something for me...is the bike moving when your clutch lever is pulled IN or when you let it out??

It is possible for a bike to go if you let the clutch out very slowly in like first gear on flat land. As for it not dieing....if you were to hit the rear brake it will die with the clutch not pulled in.

[Grieby54]

Does it move with the clutch pulled in, or no?

I'd try lubing your throttle cable and your clutch cable for sure. Take the throttle assembly apart and clean it out real well. Do you ever have a problem with your throttle getting stuck?

[Whitefox]

Wow thanks heaps for all the feedback!!! this forum is awesome.

Now to answer a few questions, sorry i took so long. Yes my bike is a yz250f meaning that it is a four stroke. My bike is moving when the clutch is pulled in!!! Meaning that the bike moves when the clutch is not engaged...

The throttle on my bike does not stick and is actually really quick in response, i can give the bike a bit of throttle and then let go and the throttle will twist back instantly.

Also what would you lube the throttle cable with? just normal oil?

I took the bike for a ride today on the trails and actually the bike went well with no problem, however after a few minutes of riding i held the clutch in and the bike started moving... i held it in to open a gate and the bike started rolling forward. I had to use my brake to stop it...

Thanks heaps for you help everyone!!! Much appreciated

[VAL]

It Could be something as simple as clutch cable adjustment. There is a slack adjuster at the clutch perch. You can loosen the lock and screw the adjuster out from the perch. This will make the clutch disengage sooner when teh clutch is pulled in. Don't adjust it too far or you will have the opposite effect, that is the clutch would be slipping all the time.
If this doesn't work you will have to take a look at the clutch basket to see if it is notched.
Keep us informed as to your progress. Good luck.

[Dirtbikindad393]

Originally Posted by VAL

It Could be something as simple as clutch cable adjustment. There is a slack adjuster at the clutch perch. You can loosen the lock and screw the adjuster out from the perch. This will make the clutch disengage sooner when teh clutch is pulled in. Don't adjust it too far or you will have the opposite effect, that is the clutch would be slipping all the time.
If this doesn't work you will have to take a look at the clutch basket to see if it is notched.
Keep us informed as to your progress. Good luck.

Val hit the nail on the head with the clutch basket. Tell me one thing, is it really hard to find neutral?

If it is hard to find neutral and the bike is rolling when the clutch is pulled in, the clutch basket is notched which does not allow the clutch to fully disengaged. The clutch basket needs to be changed. I suggest putting in a hinson clutch basket and inner hub. If you go here I've done a complete clutch basket changeout, including pictures, installing a hinson clutch basket on my 06 YZ 450. It is a very detailed "how to" type tutorial. Read this first before you start because it includes the symptoms.


Good luck and let us know what you find when you take the clutch apart.


Dane

PS; Yamaha factory baskets are soft and this is a known issue with them. When you take it apart if you can just barely catch your finger nail on the ridges in the basket its toast! To check this you will want to take the clutch cover off then take the pressure plate off and take out the first 3 or 4 plates (keep them in order). Test the basket if you see ridges or can feel ridges you need a new one. I know of a place on ebay to get them for less than you can retail.

Let us know

[Synyster06Gates]

Originally Posted by Whitefox

Now to answer a few questions, sorry i took so long. Yes my bike is a yz250f meaning that it is a four stroke.

Yeah I was just wondering cause in the picture you had a 2 stroke...

[Dirtbikindad393]

Originally Posted by Synyster06Gates

Yeah I was just wondering cause in the picture you had a 2 stroke...

In the first post I was confused because it was the symptom of when the clutch lever was in. But he said when you let it out, threw me for a curve for minute then I told my wife he misspoke and meant when the lever was in.

Notched clutch basket. Pretty easy fix just need to spend the $ to do it and the bike will run great (clutch wise).