The OBSERVED Valve Clearance thread

[Django]

This discussion leads me to question my own situation. I generally wear pretty good ear protection and the engine sounds like the proverbial sewing machine all the time. But once in a while I will forget the ear plugs and everything is louder. That's when I notice that under pretty good acceleration I hear distinct ticking from the engine. It runs as it always has with no discernible difference over time. So, is this the injectors doing their thing or valves rattling around? It's got 15k miles on it, mostly casual riding though I do prefer to keep the revs elevated (3500 to 4500 RPM are normal, I guess).
Or maybe I should just put my earplugs back in

I'd say, that ticking is produced by the injectors. Anyway, wearing of the valve drive system of the CB1100 would reduce the play of the valves, not increasing (and causing ticking). The risk is, after wearing too much, the out valves wouldn't really close anymore and would get burned.

You can see that at Cormanus' valves new clearance list.

[Inhouse Bob]

This discussion leads me to question my own situation. I generally wear pretty good ear protection and the engine sounds like the proverbial sewing machine all the time. But once in a while I will forget the ear plugs and everything is louder. That's when I notice that under pretty good acceleration I hear distinct ticking from the engine. It runs as it always has with no discernible difference over time. So, is this the injectors doing their thing or valves rattling around? It's got 15k miles on it, mostly casual riding though I do prefer to keep the revs elevated (3500 to 4500 RPM are normal, I guess).
Or maybe I should just put my earplugs back in

I'd say, that ticking is produced by the injectors. Anyway, wearing of the valve drive system of the CB1100 would reduce the play of the valves, not increasing (and causing ticking). The risk is, after wearing too much, the out valves wouldn't really close anymore and would get burned.

You can see that at Cormanus' valves new clearance list.

Thanks Django. That's what I thought, but paranoia is what it is. Now, off to change the oil!

[max]

Thanks Cormanus and Django for the good info.

After staring at the updated ( ta ) spreadsheet for a while and thinking about what it is that is actually wearing it appears that the only thing that could cause the clearance to decrease as it does is the valves and seats as they work their magic after the cams and buckets have seated in and polished up on the contact surfaces, it almost becomes predictable.

What a useful thread this turns out to be, thanks Cormanus for providing so much insight in our valve system.

[Cormanus]

I wish only that I understood my contribution. But you’re welcome.

[the Ferret]

Don't feel bad Cormanus, I didn't get anything from your chart other than a bunch of numbers. Don't know what those numbers mean though. Good thing we are smart when it comes to moderatin'

[Cormanus]

[Jurlie_imp]

This discussion leads me to question my own situation. I generally wear pretty good ear protection and the engine sounds like the proverbial sewing machine all the time. But once in a while I will forget the ear plugs and everything is louder. That's when I notice that under pretty good acceleration I hear distinct ticking from the engine. It runs as it always has with no discernible difference over time. So, is this the injectors doing their thing or valves rattling around? It's got 15k miles on it, mostly casual riding though I do prefer to keep the revs elevated (3500 to 4500 RPM are normal, I guess).
Or maybe I should just put my earplugs back in

I don't think anything went out of the spec after 15k miles... Air cooled engines are always more noisy compared to liquid cooled ones...

Also, here are my measurements.
Odo is 36k miles, last check was at 12k miles at dealer's shop and I believe no adjustment has been done.
(measurements are in mm)

Clearance; Old shim size; (Old shim marking); New Shim Size
Cyl 1:
Ex
0.31 2.012 (200) 2.050
0.33 1.976 (198) 2.025
In
0.18 2.027 (202) 2.050
0.19 2.027 (202) 2.075

Cyl 2:
Ex
0.30 1.930 (192) 1.950
0.33 1.928 (192) 1.975

In
0.18 2.029 (202) 2.050
0.20 1.981 (198) 2.025

Cyl 3:
Ex
0.32 1.910 (190) 1.950
0.32 1.908 (190) 1.950
In
0.19 1.979 (198) 2.025
0.19 1.956 (195) 2.000

Cyl 4:
Ex
0.30 1.910 (190) 1.925
0.30 1.915 (190) 1.925
In
0.21 1.956 (195) 2.025
0.21 1.981 (198) 2.050

The numbers of existing shims look not round. I think part of the reason is because I used inch micrometer and converted all values to mm. Probably some systematic error is involved.

My bike is '13, I typically keep revs between 1.5 and 4k PRM unless this is 5th gear and there is no next gear to gear up. I also accelerate aggressively most of the times.

[Cormanus]

Great. Thanks for posting, Jurlie.

[Jurlie_imp]

Great. Thanks for posting, Jurlie.

You're always welcome!
I've realized it will be useful to list shim sizes marked on them. Will fix that tomorrow as it gets late today...

[max]

Thanks Jurlie, the reason for the old and new shim sizes is simple;
1 we get an idea what shim sizes and how many are required and;
2 we learn about valve clearance behavior in our bikes.

As far as i can work it out my cb919 and the cb1100 use the same size shims ( 7.48 mm. ) and also the same shim thickness ( ranging from 1.95 to 2.05 mm ) and we need more than 3 as supplied with the usual kit of the same size.

For a quick overview we created this thread and a spreadsheet for this purpose;
https://docs.google.com/spreadsheets/d/1...=473671721
as of yet i have only bought shims with 0.05 mm interval but would like to get the in-between 0.025 interval as well for the future.

Out of interest did you un-tension the cam chain when measuring?