powervalve WILL NOT come out!

[Blitz393]

the exhaust valve on my 1992 YZ125 refuses to slip out of the cylinder... the partsfish shows that it just kinda goes out the right side.... i've been utilizing hammers and this really isn't working. WHAT am i doing wrong????

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any ideas? who has rebuilt one of these? who has done one that is similar?

Rob

[Aus_Rider_22]

Sorry I can't really help but I feel your pain! After my bore was re-plated we had some trouble getting the powervalves to go back in easily. Apparently the treatment causes different parts to expand and decrease.

WE eventually got it though.

This is probably going to sound stupid but any way:
Maybe if you could somehow heat the cylinder becuase the metal should expand and that should give enough space for valve assembly to slide out. I think you would need to heat it to fairly extreme temperatures for it to expand though.

[Blitz393]

it's not stuck, it feels like there is a lock ring or something in there because i can move it left and right about a centimeter however it feels like it 'hits' something and the parts diagram doesn't help anything. i've used punches and hammers, big hammers, and lots of cursing but it still won't come out. i'm thinking there might be a lock bolt or a spacer pressed into the cylinder somewhere because it is metal-to-metal contact. it isn't stuck but it is sticky (the reason i'm removing it)

Rob

[Spitfire]

My PV was the same exact way, it turns out that there was SO much carbon built up, that it wouldn't only come out a certain amount. We finally got it out after an hour of fighting, it took a can of 2+2 and a wooden dowel rod to pry with, but we got it!

[YZGreg]

My 250 has the same sort of PV. It's 2 pieces and there's an allen head bolt that holds the PV halves together, The bolt's on the left hand side under the cover inside the hole on the end of the PV. Once that's out it pulls apart easily from both sides. Hopefully you didn't bugger it from hammering on it since it's aluminum.

[Blitz393]

there isn't an allen head bolt in there... i wish there was... even the partsfish doesn't show one and it shows that the PV is one unit.

Rob

[YZGreg]

Well there should be. That partsfish doesn't show it on mine but you can see a line in the middle of the PV thats where they come apart. Your PV looks Identical to mine and I could move mine around and it seemed like it would come out before I got a manual that showed the allen screw. Mine was covered in carbon so I had to dig around to find it but it is there.

[Blitz393]

thanks a bunch! i'll go out to the garage weilding a propane torch and a small screwdriver... that'll chip it off

[YZGreg]

Good Luck!!

[Blitz393]

i got it out!! i cleaned up all the carbon with a toothbrush and brake clean (dont worry i put my sister's brush right back where i got it) and there it was, a 4mm allen head bolt. after like 2 hours of fiddling with it, trying to bust it loose without mashing the other end with Vice grips, i ended up shoving a rag into the exhaust port and then torquing hard on the nut so the rag caught the valve and i was able to get the bolt out. then after some careful prodding with a wooden dowel and a hammer (light taps) it came out and there was a LOT of carbon... well i fixed that quick, fast and in a hurry with 180psi and 20,000 RPM's of wire wheel and a bunch of brake cleaner. then for the cylinder i used a wire brush and brake clean and it's all shiny now.

THANKS YZgreg!!

Rob

[YZGreg]

No Problem! I don't know why they don't show it on the partsfich, what if you had to buy just one half of the PV. You would have to buy the whole thing, it doesn't make much sense to me.

[Blitz393]

it should make lots of sense... that is, $en$e... :