Lexmoto Echo valve adjustment issues

[danielbe]

Hi all, just attempted a valve check/adjustment of our 2022 Lexmoto Echo....

Engine stone cold.
It seemed the clearances were tight.
We think we got TDC as T mark against the flywheel case marker and valves at their correct positions.(we think).
Have adjusted to book recommended 0.05mm/0.1mm (in/ex).
We think we adjusted correctly.
Now sounds very tapety...and almost no power....so something has gone wrong somewhere. But where!?

For what it's worth, when we tried again the following day (cold engine) I notice that there is always tension on the rocker arm and therefore tapet to valve are always on contact. So....if it's always pressing against eachother, where's the gap we're supposed to be measuring? Link to this is here.https://photos.app.goo.gl/3nuMVzrjr2B874ez9

Very confused...

[aeroxbud]

You could be 180 degrees out on the timing.

[FrankenMech]

Valve timing is set at TDC on the compression stroke.

[snaker]

Guessin Aerox is on it.
Crankshaft spins twice as fast as the camshaft.
One revolution of the flywheel and the camshaft is positioned where a valve rocker arm is stopped and the next revolution that rocker arm is moving.
Obviously, there is no gap when that rocker arm is moving.

You can rotate the flywheel and watch for the flywheel to position at the T when both rocker arms are stopped.
That is when you check the gap

Its good to rotate the crankshaft a bunch while you watch the valve movements.
It can help to see what's happening in there and understand the action.
It don't cost nothin.

[GrumpyUnk]

You have the cover off to adjust, so you can look at the cam sprocket on the left foot side of the cam. There is a single hole and two slight scribes on the cam sprocket. Hole should be at the top, and the scribes or lines should be close to being parallel with the gasket surface of the cylinder head. That would be the cam at TDC.
The mark on the flywheel on the opposite side should line up with the mark on the casting. If concerned, remove the spark plug and use a pencil/threaded rod/dowel to check that the piston is at TDC, and then see where the marks line up. The marks would be at about 10 o'clock if you are looking directly at it (close, anyway).
If the marks line up, and the circle/scribes line up, your cam is timed properly.
The valve clearance is kind of questionable. Some say the clearance will shrink as the engine gets hot. I think the clearance increase as the engine heats, given the cast iron cylinder not 'growing' in length while the aluminum cylinder head does grow. Well, it seems that valves that do not tap cold, WILL tap when the engine gets hot, and it is not from lack of lubrication. If you are willing, you can check clearance cold and then hot, using a GO/NOGO set of feeler gauges. Get one feeler larger than your desired clearance, and the desired one, and a third smaller than desired. Measure and set cold. Start and run the engine until hot, and then measure again. My bet is that the larger will now fit. I don't think the valves elongate as much as the increase in size of the cylinder head itself.
It is almost as if setting the valves with .001" clearance(both) will end up with usable clearance once the engine is heated to operating temperature.
I have yet to have one seem to stay as quiet as it is when first started. It seems if you set minimal clearance cold, then can hear happy-tappy valves when hot, you should be good. IMO.
tom

[FrankenMech]

I don't worry much about valve noise. I got used to it with my old Ford FE with solid lifters and 68 1600cc VW. The performance difference in setting them tight versus a few thousandths loose is negligible. There is however a big problem with engine damage burning the valves and valve seats if set too tight. That is why I just use .003-.004" with the valves and engine cold. I don't like working on hot engines and even less on hot running engines. LOL