YZF 250 F valve clearance

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Rnm528

Anyone help me understand what could be the cause of not being able to get the right measurements of the valve adjustment? The manual states exhaust 0.17-0.22mm and I’m only getting at most a 0.008 mm feeler in there. On the intake it’s supposed to be 0.10-0.15 mm and I’ll be damned if I can’t get a .003 gauge in it. Let’s assume I’m not stupid and do know about mechanics and I do have the piston is at TDC. Thanks in advance!
 
SRAD97750

SRAD97750

Moderator
Staff member
Howdy,
That's the valve wear you're checking for specifically. They need to be adjusted back into spec.
If they can't be adjusted into spec with available shims, the head needs a complete valve job.
-BIG DAN:thumb:
 
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Rnm528

SRAD97750:
Howdy,
That's the valve wear you're checking for specifically. They need to be adjusted back into spec.
If they can't be adjusted into spec with available shims, the head needs a complete valve job.
-BIG DAN:thumb:
Click to expand...
BD, so that’s the norm? I was thinking I could fit an airliner in there if they were worn out?? Not the opposite. Thanks brother!
 
2Wheels

2Wheels

What year?
Have you shimmed since you’ve owned it?
If
You have to go more than .10mm it probably could use a head job or valves at the very least.
 
2Wheels

2Wheels

I’d call that zero’d out. Those heads are pretty reliable, but being so old I’ll pull it and rebuild it, or at very least inspect the valves and seats.
 
2Wheels

2Wheels

Rnm528:
Let’s assume I’m not stupid and do know about mechanics. I’m only getting at most a 0.008 mm feeler in there
Click to expand...

If you know about mechanics, you know details matter. I’m fairly certain You do not have a .008 mm feeler gauge. Get a manual, Tear that motor down to the crank and rebuild it. If if runs when you’re done, you will have learned more than you ever thought you knew. Not to mention, it’s FUN! Good luck!
 
2Wheels

2Wheels

That's beyond inappropriate it's dumb! unless you live on Galapagos or Booga Booga Africa there are better solutions. This OP is long gone but, being a 2001 4our banger it's time to go out to pasture anyway. There's a rusty headded goober on here with an unhealthy passion with the old blue iron but I wouldn't spend any money on it. At very least get a shop to pack in some BeCu but once you get it apart, the tab starts going up fast.
 
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croberts24

meh...it works. My kids have hundreds of hours on two bikes in this condition - still running strong. Yes, I'm well aware of the implications but when they have zero budget options are limited
 
2Wheels

2Wheels

The shims recess into the spring retainers though, and your bucket rests on top. Once you get to the thinnest shim it's done. Bucket doesn't spin..
 
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croberts24

agreed. That's why I take down the valve stem tip 0.010"-0.015" so bucket does not contact the retainer and I can go back to thicker shims. Obviously there's a limit that the valve stem tip cannot be any lower than the retainer counterbore. Still, it adds many years of life to hammered in seats.
 
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