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YZ125 Power Valve Pins - Using roll pins

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I just wanted to give everyone an update.  I've been using roll pins on my power valves for about 30 hours now.  I took the bike apart today to put a new ring on the piston.  The pins are working perfectly, no movement what so ever.  The bike has been running perfect since I put them in.  This is a good alternative for those that don't want to shell out the $150 plus each power valve costs from Yamaha.  They can be difficult to press in, I used a bench vice and socket.  I'll try to get to the hardware store sometime to check to see what size I used, but its obvious if you take one of your pins with you and match it up.  

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20 hours on mine and they look fine. Took about 10 minutes to do both, I used a rubber cover on the vice.

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I just wanted to give everyone an update. I've been using roll pins on my power valves for about 30 hours now. I took the bike apart today to put a new ring on the piston. The pins are working perfectly, no movement what so ever. The bike has been running perfect since I put them in. This is a good alternative for those that don't want to shell out the $150 plus each power valve costs from Yamaha. They can be difficult to press in, I used a bench vice and socket. I'll try to get to the hardware store sometime to check to see what size I used, but its obvious if you take one of your pins with you and match it up.

what are the pins and would it work on a yz 125

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Seeing as how the title of this post is "YZ125 Power Valve pins- Using roll pins", I think that the answer is most likely Yes.

oh haha yeah what are they and is it a good mod worth the time, any instructions and pics of the pins you use

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The mod is only worth it if your having problems with your stock power valve pins moving.  This is not a performance mod, this is a fix for a stock part that is not functioning properly. 

 

 

acess-roll-pin_zpsd0533fe4.jpg

 

This is what a roll pin looks like, I got mine from the local True Value hardware store. 

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The mod is only worth it if your having problems with your stock power valve pins moving. This is not a performance mod, this is a fix for a stock part that is not functioning properly.

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This is what a roll pin looks like, I got mine from the local True Value hardware store.

whitch pins are they replacing I read You have to press them in. Are they the pins on the rod that connects to the power valve linkage arm

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whitch pins are they replacing I read You have to press them in. Are they the pins on the rod that connects to the power valve linkage arm

Are you serious? Read the first post!!!

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I did and no where does it say whitch ones to replace with roll pins

How many pins are there in your PV assembly?

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How many pins are there in your PV assembly?

just two barrel like spacers on each side if the spring

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Yes, these are the pins at the ends of the power valves that engage the springs to actuate the power valves. This post was meant for those having problems with their power valves.  I didn't really think I needed to explain exactly what part of the assembly I was talking about.  

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The pins I am talking about are indicated by the orange arrows.  They can loosen up an move in the direction of the blue arrow.  This causes the springs to not engage the valve, therefore the valves stop moving.  You press out this solid pin, and press in the roll pin, making sure the seam is not contacting the springs.  This will allow the valves to move in and out again as designed. 

 

7956999052_d1c9246bbd_b_zps99a95315.jpg

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The pins I am talking about are indicated by the orange arrows. They can loosen up an move in the direction of the blue arrow. This causes the springs to not engage the valve, therefore the valves stop moving. You press out this solid pin, and press in the roll pin, making sure the seam is not contacting the springs. This will allow the valves to move in and out again as designed.

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thank you it i took my power valve cover off and the valves stick shut and some times don't move so I'll tear into it tomorrow and see what it is

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If your valves are sticking shut, you need to pull the linkage on the end of the shaft off, remove the allen head screw holding the springs apart at the center, then pull out the shaft.  Then remove the 2 allens on each power valve.  Slide out the power valves and clean any carbon off them.  Mine had a small build up of carbon near the tip where it was closest to the piston.  Clean everything with solvent till it all the black sludge is gone.  Then reassemble using a light coating of pre-mix oil to lube it all up.  Make sure after you secure the two allens on each valve that they move back and forth freely.  

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If your valves are sticking shut, you need to pull the linkage on the end of the shaft off, remove the allen head screw holding the springs apart at the center, then pull out the shaft. Then remove the 2 allens on each power valve. Slide out the power valves and clean any carbon off them. Mine had a small build up of carbon near the tip where it was closest to the piston. Clean everything with solvent till it all the black sludge is gone. Then reassemble using a light coating of pre-mix oil to lube it all up. Make sure after you secure the two allens on each valve that they move back and forth freely.

I figured the hell with it and went out and took my power valve apart tonight and I removed all sludge and read it is good to polish them I ported and polished the cylinder last week and it gained so much top end so I polished the power valves and now they slide like a dream,
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