[Adithya Pillai]

I did my first clearance check at 43000 km because my service center does not consider this a problem. Anyways here are the results of the feeler gauge.
IN Right : 16(Ok) 17(Tight)
IN Left : 18(Ok) 19(Tight)

EX Right : 35(Ok) 36(Tight)
EX Left : 29(Ok) 30(Tight)

Yes, the right EX shim has to go. 35 is far too gone 🤣🤣🤣🤣

 

[Adithya Pillai]

EX Right shim size was 1.875mm.
I ordered 1.950mm as a replacement.

 

[Tamir]

The measurement requires some experience, what exactly should be felt at the feeler gauge, what are those feelings of GO, and NOT GO, or for example tight versus easy sliding or slide fit. Because if you use a lot of force, you can sometimes insert the feeler gauge with a hard slide.
And if you approach the feeler gauge at an angle not parallel to the shim, then this can also create an error in the measurement (a feeling of pressure, when in practice the clearance is large and loose).

I recommend to look at YouTube for what this slide fit is.
I have such a video somewhere, I will try to find it and upload it myself to my YouTube channel (only the moment of feeler gauge measurement).

 

[Tamir]

Loose or tight?
The first time I adjusted it to be more tight.
Now I loosened it, I corrected one size back (minus 0.025 for each of the shims)

I expect better compression (but I don't go back to check compression), which may help with easier cold weather starts.
More loose means more exhaust gas pressure at EX outlet, therefore an engine that heats up a little more, and more wear on the valve seat.
More loose means a little less wear on the valve actuation mechanism.

In the previous situation, one step more tight(0.025), I reached a fuel consumption of 39 km/l. It's hard for me to say that this is the reason, I'm just reflecting what happened.

If I feel the change in the new shims system I will share.

 

[Adithya Pillai]

@Tamir did all the research before opening the head.
I did the thickness check with a calibrated micrometer.

what are those feelings of GO, and NOT GO,

"Ok" means the gauge doesn't need much effort to slide in and out.
"Tight" means don't go in smoothly and need some effort to go in and out.
The gauge was put parallel to the shim and not at an angle.
I decided to go for a 1.950mm shim giving me an expected clearance of 0.275mm

 

[Tamir]

my service center does not consider this a problem.

At normal use, when you don't ride sporty and hard, when you don't let the engine scream all the time, in the normal case these shims have no tendency to go out of adjustment.

The mechanic advised you correctly, because the repair is very expensive (many hours of work), and even after an inspection if it finds that it is possible to be more precise, the effect will be negligible.
For example: The generic kits of shims are sold in 0.05mm increments. This is for giving proportions regarding the accuracy of valve adjustment.
Another amplexe: Honda supplies shims in 0.025mm intervals, but the feeler gauges themselves are in 0.02-0.03mm intervals.

As long as it is not about some super dramatic out from tuning it is almost meaningless, and if there is a dramatic deviation from the specification then the mechanic hears it, but then there might also be a chance of damage to the valves.

Adithya Pillai, people like you and me adjusted valves because we can, or because it's our hobby, or both.

In my opinion, the manufacturer himself did not intend for us to mess with it, because otherwise why did he make the procedure so difficult and long? In my opinion, from the manufacturer's point of view, valves are adjusted once when the engine is outside the frame, either because it is a new engine, or because it is an engine after an overhaul.

 

[Tamir]

"Ok" means the gauge doesn't need much effort to slide in and out.
"Tight" means don't go in smoothly and need some effort to go in and out.

These are the video materials I found, and now also edited...