Make sure the engine is overnight cold before taking the measurements.
Yup. Dropped it off this morning. Work will start tomorrow AM.
Make sure the engine is overnight cold before taking the measurements.
And of course learn all you can while watching and maybe you'll be able to do it yourself next time...
I'm hoping someone will need this done and will let me assist.
There is a notable difference between tight and loose when using feeler gauges. If .010" will not pass at all that is pretty self evident but a "loose" .009 feeler indicates the clearance is closer to .00975 than it is .00925 and so on. If .010 will not pass and .009 has little drag when passing I record the clearance as .009+. Over time and several checks I have seen .009+ go to .009- so even though I did not know the intermediate clearances between .009 and .010 historically I could see the valve was tightening. Eventually that valve went under .009 to .008+ which I knew was .00875 or thereabouts and out of spec.
I'm curious about the science here.
1. I assume the clearances only go in one direction, i/e., they only tighten? Or, do they also loosen?
2. What is actually going on within the valve system that is causing the clearance to tighten? Or loosen?
3. Some valve clearances change with mileage and others don't...is this true? If so, why is that? Are all of the valve clearances identical when the bike is new?
4. Do some clearances tighten (or loosen) and then stop moving? Sup with that?
Using this chart is not wrong and by all means use it if you want. But it kind of makes the job much more complicated than it needs to be. If your clearance is too tight just put in the next smaller HONDA shim as they come in .001 increments. If the measurement is loose, put in the next bigger shim.Here's a web site to calculate needed shim sizes.
Just use the form multiple times to get readings for the ST
http://klr650.carguy.org/shims.html
First of all I am not a trained mechanic or engineer. My dad was a mechanic and and I learned a lot from him as he maintained our cars and later his and my motorcycles and sailboat engines.
1. My experience is that valve clearances tighten over time and do not loosen. If they change at all of course. Some remain stable between service intervals at least to the time or mileage I owned them.
2. The seating surface, the valve seat, the valve must meet thousands of times a minute gradually wears and the valve gradually seats deeper into the cylinder head. This introduces less clearance between the valve stem and the mechanism above it that opens and closes the valve. The valve face that meets the valve seat can also wear or get hammered thinner around the edges.
3. I do not know why but yes some valve clearances will remain stable or move less than others in the same engine. This might be from variations in metallurgy of the parts involved or localized temperature or oiling variations that influence wear. With today's very tight manufacturing tolerances and precise assembly procedures I suppose it might be possible an engine starts out with all valves at the same clearances but more likely there is some differences greater than .0005".
4. It is said that most of the changes occur in the first service interval but I don't know why or if that is true. I believe the practice of regular checks is to establish a baseline so wear patterns can be established and monitored as mileage or hours of service pile up.
Good to hear. So what was the final numbers?
All of the intake valve clearances were .006" and all of the exhaust clearances were .0010" (with one being a bit tight and one being a bit loose, but not enough to be considered .009" or .011")