YZ250X Head

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That's Mister Black Flag To You
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This came in the mail today......excited to get this installed and do some more riding.

Since none of you ride sit fucking tight and I will post some more epic shit that you guys can watch from the comfort of your barkolounge chairs.

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Master-Cylinder

Duck Loving Curmudgeon and Legendary Race Wrench
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I ran VHM two piece heads back in the 90's. I still have a bucket full of them, from 10.2cc's and up to around 10.8cc. The outer shells are gold colored. The trick heads have bronze inserts in the squish band to quell detonation. The inserts would eventually crack, but then, racing ain't cheap.
 

RollieFree

BAMF
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I ran VHM two piece heads back in the 90's. I still have a bucket full of them, from 10.2cc's and up to around 10.8cc. The outer shells are gold colored. The trick heads have bronze inserts in the squish band to quell detonation. The inserts would eventually crack, but then, racing ain't cheap.
You ever worked on any of the aftermarket Krauser 4 valve heads on BMW stuff from the 70’s?
RF
 

Master-Cylinder

Duck Loving Curmudgeon and Legendary Race Wrench
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I need to take the engine completely apart on mind and clean out the built up sludge in it. Mind has the Earles front end. Love the look of them.
 

RollieFree

BAMF
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I need to take the engine completely apart on mind and clean out the built up sludge in it. Mind has the Earles front end. Love the look of them.
My 64 had the earles too. Great handling little bike. Not much power but fun to run around on. That crank is pressed together and has to come apart to clean the slingers. I have never done that. The /5 model like the one I kept is not as good looking but a much better motorcycle.
RF
 
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That's Mister Black Flag To You
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Going to have to finish it in the morning as I left my calipers to measure squish at the shop along with my torque wrench.

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Master-Cylinder

Duck Loving Curmudgeon and Legendary Race Wrench
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Using hollow rosin core 60/40 solder to measure the squish? Run it front to back, to get a good measurement.
Don't want the stuff to be too large diameter. I used to buy rolls of it at Radio Shack.
 

Master-Cylinder

Duck Loving Curmudgeon and Legendary Race Wrench
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We'd run .45mm squish. Any tighter, and you'd probably lose the crank. Some tracks, we'd run the thing at 12,750+ RPM for up to 30 seconds at a tyme. From the chicane at Daytona to turn one. Also at the front straight at Road America, and Brainerd.
I think only in the desert, would you run a dirt bike that hard, WFO in top gear, that long. Or longer.
 
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That's Mister Black Flag To You
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Yes planned on using hollow core solder and we are going to be at about .05 squish which is way better than the .110 that comes from the factory.
 
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Master-Cylinder

Duck Loving Curmudgeon and Legendary Race Wrench
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Yes planned on using hollow core solder and we are going to be at about .05 squish which is way better than the .110 that comes from the factory.
That in farmer inches? That's 1.27mm, ain't gonna have any problems with a canyon that deep. My .45 is 0.0177 farmer inch.
 
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That's Mister Black Flag To You
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That's very pretty, but I'm curious why you didn't just fire up the machine and make it yourself :)

I know, I know. . .

Design, programming, setup . . . blah blah blah
I am working on something much bigger at the moment and for $200 it checks a box that I no longer need to worry about
 
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That's Mister Black Flag To You
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This morning I got up early and went to the shop for a few tools so I could finish the job. Installed the head and check squish and ended up .045 which is perfect.

She started on the first kick this morning while being cold. Took her around the block, power is broader in the range, throttle is more responsive and overall seems better.

Going to take her for a real ride here shortly

 

maui

Big Bore diggidy mayhem
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looks good Scott. Nice when you don't have a bunch of parts left over too....or so I am told.
 

Master-Cylinder

Duck Loving Curmudgeon and Legendary Race Wrench
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when CZ Eddie started his bike and I walked up behind him with a bolt and said this just came out of the silencer. The look on his face was priceless.
:lol:

I'd be at the track and a guy would have just put the top end back on his TZ250 or RS250, I'd "pick up" a wrist pin clip off his work bench and axe him if he forgot something. It was a hoot.
 
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