Cr125 power valve setup? Linkage arm?

[hondahead98]

I have not ridden my 125 for about six months. It had done a head gasket and I did the water pump seal just in case. I also installed a new piston and rings.

I am pretty sure I must have set the powervalve linkage arm up wrong. I am looking for a manual or diagram on how to set the linkage arm up?

The bike is braking down at high revs. I tried swapping the carby (had a spare!) and changed the spark plug no change. So pretty sure it is powervalve

[KcDavis]

Did you check to see if the powervalve is operating correctly or not?

[hondahead98]

The bike is a 2003 125 by the way. I haven't checked that the power valve is operating correctly. When I had the right had side cover off and the powervalve linkage out I found a manual that described how to set it up. I've searched everywhere but cannot seem to find it. I just want to double check what I know I've play with first.

A picture or diagram on how to line up the powervalve linkage would be good!

[b1m3x8]

A picture or diagram on how to line up the powervalve linkage would be good!

http://www.motosport.com/dirtbike/oem-parts/HONDA/2003/CR125/EXHAUST-VALVE-%28'02_'03%29?mmy_source=oem

[Luvskris328]

My linkage arm won't reach the pin on mine. Any advice on how to fix that?

[cloead]

My linkage arm won't reach the pin on mine. Any advice on how to fix that?

Mine is the same way.. could use some advice on that.

 

I got it to reach by fighting the springs holding it down, but the bike runs like crap and won't get into the powerband in first and way late in second and has a hard time staying in it.

[Luvskris328]

Your going to have to pull the case off and adjust the gear that control that linkage arm from the inside. It's pretty simple, just take the bolts out and turn the gear to where the linkage arm will be high enough to fit on like it did before.

[cloead]

Your going to have to pull the case off and adjust the gear that control that linkage arm from the inside. It's pretty simple, just take the bolts out and turn the gear to where the linkage arm will be high enough to fit on like it did before.

 

By case do you mean cover ?  Or like split the cases again?

[Luvskris328]

Got to take the cover off then the next section

[Steelmesh]

Check out this: how the linkage should sit in the crankcase cover 92-97 CR125

http://i.imgur.com/2jXMvIj.png

[cloead]

Thanks for that. 

 

So I'm assuming when the power valve is rotated all the way to the left (counter clockwise) it is closed?

 

I raised the arm up so it slid over the post on the power valve when the valve is turned all the way to the left, which is where it seemed to like to sit.

 

Rode the bike and it seems to be fixed but I only got a few laps in before someone called the cops.. love living in suburbia sometimes.    Before it would barely get into the powerband and would never stay there.  My quick 1-2-3 shifts seemed to be MUCH better after doing this.

[MSFIT]

Thanks for that. 

 

So I'm assuming when the power valve is rotated all the way to the left (counter clockwise) it is closed?

 

I raised the arm up so it slid over the post on the power valve when the valve is turned all the way to the left, which is where it seemed to like to sit.

 

Rode the bike and it seems to be fixed but I only got a few laps in before someone called the cops.. love living in suburbia sometimes.    Before it would barely get into the powerband and would never stay there.  My quick 1-2-3 shifts seemed to be MUCH better after doing this.

 

From the manual:

 

https://drive.google.com/file/d/0B0Etc82a4kHMdXhqQUNLdFUxTk0/view?usp=sharing

[cloead]

From the manual:

 

https://drive.google.com/file/d/0B0Etc82a4kHMdXhqQUNLdFUxTk0/view?usp=sharing

Nice! So I have it on there correctly now.  Rode it on a track yesterday and she sure does rip compared to before. 

 

You wouldn't happen to have the rest of the manual available would you?... ?

[Micscience]

I am in the same predicament. I followed the manual and placed the arm linkage exactly as the manual says took it for a rip and that ride the bike seemed fine for a few blocks but then Iost the powerband again especially in the early gears and today I went to check where the linkage was sitting  and it is back to the bottom where the freaking power valve is supposed to be opened but in actuality is closed so some how my power valve linkage keeps getting out of adjustment. This bike has been nothing problems I think I am going to stick to 4 strokes after this.  /cry All I want to do is rip.

Edited July 24, 2020 by Micscience

[Micscience]

For the record the bike seems to be running good so far. I adjusted the power valve once I started playing with both arms I got them to open and close at the same time which I believe they wern't doing before I adjusted due to the lack of power in the early gears. I also got a new top end and rebuilt the transmission. The previous owner messed with the tranny because the washers were off. I had to  go through it. I bought the bike for cheap but If I went back I think I would have bought a good running bike this 2 stroke learning experience was a struggle with a 6 day work week. Two stroke engine case gaskets are so finicky. I honestly believe it is easier to fix four strokes. Two strokes are faster and easier to disassemble that is true but they are harder to get running right in my experience so far. Anyways thanks for the help guys I did learn a lot about my bike though like it has 4 points of idle adjustment which is kind of ridiculous.