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What do you do when your valve clearance is just barely in spec?

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I just finished checking my valve clearances. The front cylinder was good all around; nearly right in the middle of the range. However, my rear exhaust valves were both at 0.008" (in spec is 0.008-0.012). This is within spec, but just barely. Changing shims is a pain in the ass, so I just left them as is. Though, I will be checking them in about 7,000 miles next, rather than the recommended 14,000.

What do you guys do when your clearance is in spec, but just barely?
 

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If they're in spec, leave it alone. There's no benefit in opening up those clearances more, and there's a pretty good chance they've moved all they're going to move for a long time.
 

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I just finished checking my valve clearances. The front cylinder was good all around; nearly right in the middle of the range. However, my rear exhaust valves were both at 0.008" (in spec is 0.008-0.012). This is within spec, but just barely. Changing shims is a pain in the ass, so I just left them as is. Though, I will be checking them in about 7,000 miles next, rather than the recommended 14,000.

What do you guys do when your clearance is in spec, but just barely?
the Suzuki spec takes into account how much potential there is for seat erosion over the next 15k

while valve adjustment is the most important service not to ignore, that doesn't mean it needs to be done more often than recommendations
 

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As fenderf and Randy said, in spec is in spec, no need to make adjustment, or check sooner.

Also, manufactures are very conservative with specs like this, and consideration is made for engines run at their limits. High RPM pounds the valve seats (the main cause of tightening clearance) waaay more than low RPM (double RPM = 4x the force, 2x as often), so if an engine has an easy life, the valves will hold spec for a long, long time; in many cases may never need adjustment.

The first valve check/adjustment is the most important since it also accounts for assembly/manufacturing tolerance and initial wear-in.

In the 80s Suzuki required shim check at the 600mile service, for this reason. Manufacturing precision/tolerance has improved over the decades (or perhaps the data has proven it unnecessary?) making the 600mile check no longer necessary.
 

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For those that say 'it's in spec, so you won't notice any difference adjusting them'....I beg to differ. Back when I was much more adventurous, I took the time to adjust the valves on several engines to the minimum clearance and then to the maximums to see what/if there was any difference in how they ran. There WAS an easily discernible difference between the two extremes.

On the SV1K, going from minimum clearance to maximum will decrease the overlap nearly 5 degrees.(or thereabouts) The valves open and close a couple/three degrees later. You CAN feel this! Going from max to min's will make it idle smoother and pull better down low in the revs. Mine picked up over 300 rpms at idle when the minimum valves (I had 3) were set to max. along with the others that were middling. Threw the synch way out too. It does make a difference.

Depending on what you want, you can tune the engine with the clearances. Want better mileage? Open them up. Maximum top end power? Close them up. Tighter clearances makes the cams act a little bigger...but can get you in trouble if you run it too hard with them too tight. In the USA, on the street, you probably can't go wrong, but in Germany or other places where unlimited WOT could be had...you might want to be conservative and leave some room for them to grow.

One of the old tricks building racing engines was to experiment with valve lash. Tighten them up and see if the power improves. If it does, you need a bigger cam. Lose power? Your cam is borderline too big so you should open the lash or put in a smaller cam.

Just trying to say if you are picky about how your bike runs, choose your clearances and make them all the same....don't accept 'anywhere in the specs is good enough'. This works the same for automobile wheel alignments...don't accept anything in the 'OK' range. Just an opinion from an old and opinionated guy.:)
 
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