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Post by pmatulew on Jul 28, 2015 4:43:18 GMT -6
Now that's a completely different animal. I can honestly say I've never seen an engine with external valve adjusters like that. Clean and simple. Now I'm going to have to look it up to find out how that is arranged inside. And also what the intended adjustment procedure is.
Doing what he does in the video will probably get you very close. Doing it with the engine warmed up to operating temperature will be best.
Remember, ticking valves are happy valves.
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Post by pmatulew on Jul 27, 2015 14:46:34 GMT -6
Oh, and be glad you don't have shims and buckets to deal with!  |
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Post by pmatulew on Jul 27, 2015 13:57:11 GMT -6
Every engine type has it's own voice. Valve tick is just part of the symphony. Theoretically speaking, if the designer has done his testing properly, and the oil viscosity is correct, and the RPM, and operating temperature is within design parameters, and the stars and planets align on the second Monday of the week, the valve train will have a miniscule amount of clearance when running. (Running hard under load. Not necessarily when loafing at idle.) The clearance measurement in the service manual is extrapolated backward from that perfect world scenario, (with maybe an extra "0.001" thrown in for good luck.) A little loose is better than a little tight. Also the valves and valve seats in Chinese GY6 motors tend toward the soft side. After a few hundred miles they can bed themselves deeper (recede) and the clearance can shrink to nothing. Hello burnt valve.  Usually you can tell when it's time for an adjustment because the motor is hard to start and not performing like it used to. |
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Post by pmatulew on Jul 27, 2015 9:10:34 GMT -6
Whoa! Time out! Please don't burn your valves. Exhaust valve clearance is critical to the life of your motor.
You absolutely must use feeler gauges to set the valve clearance!
The engine designers are very specific about valve clearance for a reason. Too much gap and the valves are really noisy and don't open fully. Too little gap and the valve may not close completely or get enough dwell time when closed to dissipate the combustion heat. If that happens you can burn a hole in the edge of the valve or the valve seat. That would be bad. If you have them set so that they are not making any noise then they are too tight. Ticking valves are happy valves. Only engines with hydraulic lifters that adjust automatically don't have ticking valves. Scooter engines don't have those.
If getting to the flywheel marks is a problem on your machine you can skip those steps just by making sure that the rocker arm you are adjusting is resting on the low part of the cam rather than up on the bump. The cam lobes are egg shaped. Half of it is short round, the other half is the tall bump. Just blip the starter button until the cam rotates to where you want it. (or use the kick start if you have one to gently rotate the engine)
Also you need to make these adjustment when the engine is cold (room temperature). Depending on the particular engine design the valve clearance could get tighter or looser when the engine is hot. The only valid reference point you have is to work on the engine when it is cold.
As far as access to the motor under the body plastic you're on your own. Every machine is different and you just have to deal with it as best you can.
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