No power please reply

[YzRacer#53]

Ok on my 2002 YZ134, It runs great at idle sounds normal and everything. But in gear after low end, mid-top end getting on the throttle it sounds like it wants to drown its self and it has no power at all it just has a power off the line then it feels like it has no power. The spark plug came out tan. I just rebuilt the thing 2 weeks ago.

[superrooster]

1. Check your reeds
2. Check your spark plug wire for corrosion.....

[YzRacer#53]

It runs fine in nuetral so i dont believe its the spark plug wire.

[superrooster]

Well....I think you may have blown one of your seals (in the lower end of the motor)......do you let it warm up properly???

[drman]

Probably the powervalve.

[YzRacer#53]

I thought it was the powervalve myself yes i do let it warm up properly. I'll go rip off the exhaust and cover and see if the linkage is connected ill re post soon.

[superrooster]

I keep forgeting those dang powervavles....mabye thats whats wrong with my bike now (having the same problem on my 250... brb)

[YzRacer#53]

Well the linkage is connected.... I dont know what to do im so po'd right now!

[Mr.Boof]

powervalve...

[drman]

Yeah...the linkage can be connected and it still not work..usually they get stuck because of carbon buildup. Leave the powervalve cover off...put the pipe back on and start it to see if it moves when you rev the bike.

[YzRacer#53]

Ok i'll try that tommorrow morning

[YzRacer#53]

What would I have to do in order to clean my power valve? would I have to remove the cylinder??

[drman]

Yeah, you'd be better off doing that, you could clean it completely. Did you clean it when you rebuilt it?

[YzRacer#53]

Ok I revved it in nuetral and the linkage does not move at all there is also a rattling inside the motor is sounds like. I did not take the power valve out to clean it I just sprayed everything really well till it looked new. So the linkage does not move when revving it in nuetral so what should I do about cleaning this what do I have to remove in order to clean it?

[YzRacer#53]

I dont want to remove the cylinder so how should I go about this?

[YzRacer#53]

??????

[Cr125zrule]

take apart what u can get to!! and clean it all down real good,u could use some wet and dry sandpaper on the slides

[02mncr250]

Depending the year of YZ,

is there a side cover that houses the linkage for the power valve?

They use to connect to the case and have some sort of inertia to move dependant on RPM.

Check that

Also,

Did you possibly hook up the power valve 180 degrees off? That would mean that when it is off, it should be flush with the exhause port.

What year of YZ are we talking about?

[Crazy]

As for the yz powervalve, at least on 250s, you cant put it in backwards. Its notched. Id assume that theyd make the 125 valves the same. Just look on your lefthand side of your motor. There should be 5 bolts or so, then underneith it there is the backing plate for the powervalve which has the notches on it to limit the movement (3 screws?). On the opposite side there is a cover that looks kinda like a "P". Under this is your powervalve actuating rod and other side of your powervalve. You can take the rod off via the bolt directly to the powervalve. Now that the linkage is all the way off. There is a hole in the center of the powervalve. Use a allen and unscrew the powervalve, which is 2 halves. Once this allen bolt is out you can pull each half out from its hole then polish it back to new.

[YzRacer#53]

Ok I took it apart the bridge in between the 2 exhaust ports wore a groove into my piston and my ring so I guess it would loose compression after warm up n get no power so I guess I can ship it out to be plated monday...