Excessive Valve Clearance?

I'm in the process of checking the valve clearances on my Maxim 550, but I'm getting some surprisingly high numbers. As I understand it, the valves should get tighter with age. I've measured the following:

Code:

        1     2     3     4
I     .381  .356  .406   .356
E     .457  .508  .508   .508

I'm wondering if somehow I'm measuring wrong as those numbers seem way out of whack for a bike with just over 10k miles. The engine is completely "cold" (hasn't been running for a week), but it's a fairly warm (high 70s) day outside. Could that explain the high numbers?

 

What exactly are those measurements? How are you measuring?

Something isn't making sense, you're right about that. They should get tighter with age. At 10K if never touched, they should all be tight or at the "tight end" of their spec.

 

measuring at TDC or 12 o'clock?

 

Those measurements are coming off a SAE/Metric feeler gauge (I haven't found a primary metric gauge set locally). Measuring with the cam facing 180 from the valve bucket (~45 from vertical).

Only other theory that I can come up with is that the valves are seriously gunked up. I had changed the spark plugs and they fouled within 30 minutes of run time because the PO had overfilled the bike with oil (I was none the wiser at the time...the filler cap has a dipstick and I made the same assumption the PO did). Could that be the issue here?

 

So are those fractions of an inch, metric fractions, or ???

The only thing that could explain them being super loose would be if the valves aren't closing fully.

Your filler cap should NOT have a dipstick. A dipstick long enough to be effective would hit the clutch. You filler cap should just be a cap.

 

Metric decimals...millimeters to be precise.

To clarify my previous post - I'm wondering if it's possible to have accumulated enough carbon gunk on the valve/valve seats to be offsetting the valves so they are no longer closing all the way.

It does indeed have a dipstick (must've been a part from another bike with the same thread), and of course isn't long enough to be of use, but the PO filled it up to the line. I drained at least 3.5 QT when I changed the oil.

 

Anything is possible; and that's a good possibility. Start by pulling the exhaust system and watching the valves "work" thru the ports as you rotate the motor slowly. (It beats pulling the head straight away.)

 

I pulled the #1 header (cylinder with the worst carbon buildup) and couldn't see much of anything out of the ordinary, so everything got put back together this morning (post carb clean, clunk test, bench synch, vacuum leak fix) and ran the bike. I was hoping running it "clean" for a few minutes would blast out some of the crap that had accumulated. Still getting symptoms like the carbs are way out of sync (hanging up at high rpm after revving the throttle, quitting at normal idle speed). I'm planning to take another look at the clearances tomorrow to see if anything has changed. I know I'm shooting in the dark here, but are those symptoms consistent with stuck or too loose valves as well?

edit: another thought: would a compression test be a good indication of the valve seating condition?