yz 125 problem

just bought a 04 yz 125 blown up replaced piston it has an 05 motor in it... anyway starts fine now but wont hit the.powerband at all starts and idles fine just has.no power was thinking its got a bad stator does anyone have the readings its supposed to give out?? the bike has given me alot of shit so far the piston wasnt right at first was standard size but too tall for the head it has a yrrd head so kept hitting it for some reason anyway I fixed that by putting a double base gasket down dont no if that would be a cause of no powerband??? im pretty sure its the stator though if anyone can help me with resistance or voltage readings??
 
I don't think it's the stator.
Piston installed w/the arrow pointing at the exhaust port? Carb clean? Very clean? Powervalve working properly?
What is a yrrd head?
 
I don't think it's the stator.
Piston installed w/the arrow pointing at the exhaust port? Carb clean? Very clean? Powervalve working properly?
What is a yrrd head?

Yamaha Racing R&D.......after checking I was wrong it's Yamaha Rinaldi Racing Development.....I was close.
 
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Explain not hitting power band?
Feals boggy at the top?
Sputters and hesitates at the mid to top?
Few things.
1 carburetor and jetting.
2 clogged up silencer.
3 timing.
 
just bought a 04 yz 125 blown up replaced piston it has an 05 motor in it... anyway starts fine now but wont hit the.powerband at all starts and idles fine just has.no power was thinking its got a bad stator does anyone have the readings its supposed to give out?? the bike has given me alot of shit so far the piston wasnt right at first was standard size but too tall for the head it has a yrrd head so kept hitting it for some reason anyway I fixed that by putting a double base gasket down dont no if that would be a cause of no powerband??? im pretty sure its the stator though if anyone can help me with resistance or voltage readings??

I do know that double base gasket will advance the port timing, which I believe moves the powerband to a higher rpm range, it shouldn't cause horsepower to change though, just where it's peak is.
 
I do know that double base gasket will advance the port timing, which I believe moves the powerband to a higher rpm range, it shouldn't cause horsepower to change though, just where it's peak is.
Do you think that minimum of a thickness would cause a noticeable change if that was the only thing wrong? I mean hell, an extra gasket is only a cunt hair off the ports. However, I have never really looked into it.
 
Do you think that minimum of a thickness would cause a noticeable change if that was the only thing wrong? I mean hell, an extra gasket is only a cunt hair off the ports. However, I have never really looked into it.

I don't know how much either...I just know it does, never screwed with port timing, so I don't know how much is noticeable. But my point was that no matter how much it changed it wouldn't reduce power, just move it.
 
all in the right way carn clean and yeah I knew it would advance the peak power but it litteraly gets no power pull the throttle back and it stays at about 2000rpm! just wont go no further and yeah it is.an 05 motor had the trouble of buying an 04 piston at first when it got here I realised it was wrong as piston had a port.at the back the 05s dont! should have checked the engine numbers though my mistake lol
 
So you have a steel frame with the 05 motor? 6 speed?

Did you ever see it run before it blewup and you ended up with it?

Anyway, go back to palmers question on sputtering or dieing. Add this, does anything change if you roll the throttle on really slowly?
 
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yeah steel frame 04 with 05 motor...god knows why?! and no didnt see it run but was off an friend of a friend who said was a mint runner! and nothing really changes much when I twist the throttle stays at the same rpm throughout the whole throttle! going to double check everything when I can and get the multimeter out if needs be
 
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