2001 KX250 poweret returnspring failure?.

[kimoajaj]

2001 KX250 throttle position sensor returnspring failure?.

Hi!

Yesterday when I was out riding something strange occured to my bike.

I was riding at a beach, and was also riding a little in the water, sometimes the water "splashed" all over the bike, however I don`t know if this is related to the problem.

Anyway, I was about to pop a wheelie, I came almost to a dead stop and then suddenly the bike stopped, just as if I hit the stop button. I thought the sparkplug fouled, so I went home and picked up a new plug, threw it in the cyl and tried to crank her up. No difference.
When I looked at the old sparkplug it had a nice tan, chocolate color, so it wasn`t the plug after all.

I then thought that maybe water had made it`s way into the carb, so I laid the bike down on it`s side to drain the float chamber.

Then I tried cranking it up again, and it started.
However, when I tried to rew it , it started burbling, but it cleared up after a little while, so I thought it was water in my carb.

I also noticed that the throttle handle - operation was wierd. When I gave it throttle I suddenly felt a "stop" in the movement of the throttle, it didn`t require much force to get over the "stop" but I felt that something was wrong.

I rode the bike home at low rpm and today I remove the carb.

Took the carb off today and I found out what was causing the wierd throttle feel/operation.

It seems like the TPS arm has came "further" out and the return spring-tap is hitting the carb wall when giving much throttle.

Here are some pictures:

Here you can see were the spring tap will hit:

I was able to push it back to normal postion with my finger:

But it came out again just as easy.

I checked the parts diagram and it seems like the part is a single unit with no removable parts or anything.

What could have happened?.

Could it have something to do with the burbling?.

When I rode the bike home it seemed to rew as normal, with no burbling, but the throttle operation wasn`t smooth, suddenly I felt the "stop" in the rotation of the throttle, but I think the powerjet still worked?.

Gees I wanna go riding !!!

Oh here`s a little wheelie pic.

Joakim.

 

[Chokey]

That's not the powerjet, it's the throttle position sensor. Clearly, it has come loose from it's shaft. I believe they are just a press fit, with the end of the shaft peened.

 

[kimoajaj]

Gees man I wasn`t thinking clearly!. (gees)

What does "peened" mean?. You see I`m from Norway so I don`t know all the english words.

It has to be possible to remove the "lever" from the sensor, if not it cannot be repaired since it would be impossible to get the mechanism out of the carb.

Will I need a new one or do you think I can fix it?.

 

[kimoajaj]

What does the TPS do ?.
Adjust the ignition according to the throttle position?. Or something like that?.

 

[Anssi]

Potentially the information it provides is used when adjusting the ignition and the powerjet. Not sure about your particular bike.

 

[kimoajaj]

OK thanks Anssi.. :).

Gees anyone know what I should do with this?.

Hope I wount have to replace the TPS! ?

 

[kimoajaj]

Anyone?.

How much does a TPS cost?.

 

[xxBLAZExx]

Its like $50 at bikebandit.com- part# 1469-001

 

[kimoajaj]

Hey Blaze ! Thanks for the info !! GREAT !:)
Sweet site !.

I removed the TPS today, (would have done it before if I knew I had the right screw-bits, didn`t think I had them, but I had).
I can`t seem to find anything broken, but there was a loose little circlip, however I can`t seem to find out how the citclip possibly can "hold" it together.

I wonder if all the "parts" comes with the sensoer, like the arm, circlip and little black plastic piece.. ?.

I shot some pics of it:

The tiny little black plastic piece sits loose in the sensor it`s self, and it also sits "loose" in the arm, so I can`t see how this is held together. Wierd!

Guess I will have to fiddle around with it and maybe I`ll see how it`s put together.

Hmmm

 

[kimoajaj]

HEY GUYS !

Gees I feel like a stupid idiot, hehe.
I went back to my workshop and took a look at the parts. I didn`t realize that the circlip was attached on the inside of the "house" so that it keeps the axle from falling out.

I tried to put the circlip back on and it was a loose fit, so I will try to find a new circlip and if I don`t I`ll try to "squeeze" the old one together a little so that it will be a tighter fit.

I`m so glad that I don`t have to buy any parts:).

Another question, could this be the reason for my engine stopping that day?. I was at low speed, almost standing still with the clutch in, at idle, and then it just died. Wouldn`t fire up, changed plug and still wouldn`t start. I laid the bike on the side to drain the float chamber for any obstacles, also took the plug out and rolled the bike (in gear), then put plug back in and then it started. At that point I noticed the wierd throttle behaviour, from the loose TPS arm.

The bike ran wierd when I gave it gas and "burbled" , but when I kept it pinned for a little while, it ran ok, but it kept doing it all the time, burbled all the time before I reached top rpm.

I guess this comes from the not-working tps?. Since the axle came out, the rotating movement of the TPS arm couldn`t have been transfered to the TPS itself, so I guess it was "disconnected" .

Gees can`t wait to go riding:). Will put it back together as soon as I find a circlip and I`m not at work:).

Joakim