Missing bolts

[GBDamo]

Was taking the missus out last week and thought best to give the bike a quick once over and was more than a little disturbed to find two bolts missing.

These were,

M10x30 that bolts the left side crash bar to the engine block
M12x50 that bolts the left side rear frame to the engine block

Now, I've since been round the bike and checked all other major, and accessible, fixings for torque and none were in any way loose so I find it hard to believe these two have worked loose completely and fallen out without my noticing. There was no sign of damage to the threads, which I'd expect to see if a loose (Steel in Ally) bolt had been rattling round for a few weeks before falling out.

So I have three lines of inquiry:-

1, They have worked loose, fallen out and I'm a fuckwit for not noticing.

2, They have been stolen whilst the bike has been parked up and I'm a fuckwit for not noticing.

3, They have not been replaced after servicing and I'm a fuckwit for not noticing.

All three seem unlikely but I was wondering if there would be any cause to remove these bolts during a service, the only possibility I can see is to gain access to the oil cooler line banjo, but is this something that would/should be done?

There's not a lot to be done, I've bought new and replaced the bolts and washers, but would like to see what people feel is the likeliest cause.

Ever seen anything similar?

 

[Mr K]

I've found my left side crash bar bolt loose before.

 

[Norfolk Tiger]

I've found my left side crash bar bolt loose before.

It has been said that you have a screw loose

 

[Mr K]

It has been said that you have a screw loose

 

[DGB]

You didn't say what bike it is so I'm going to make assumptions.
If they are the bolts I'm thinking of, have you had any work done to the clutch or that area? And/or have you had valve clearances checked recently?

 

[GBDamo]

You didn't say what bike it is so I'm going to make assumptions.
If they are the bolts I'm thinking of, have you had any work done to the clutch or that area? And/or have you had valve clearances checked recently?

Valve clearances should have been checked at the last service,

Ignore the arrow

Not sure if this is the exact model but the bolts in question are either side of the oil cooler line banjo, with crash bars fitted the left hole would take the M10x30.

Why would these come out for valve clearance?

And it's a 2011 GSA

 

[Bendy toy]

The bottom crash bar bolts shake loose as do the M6 bolts just under the petrol tank. The latter are a pain in the are on my bike always checking - often loose.
The frame mount could have dropped out a very long time ago. How clean are the threads?

 

[GBDamo]

The bottom crash bar bolts shake loose as do the M6 bolts just under the petrol tank. The latter are a pain in the are on my bike always checking - often loose.
The frame mount could have dropped out a very long time ago. How clean are the threads?

I've thread locked a lot of the smaller ones for that reason, in fact it was only the M6 on the underside of the cross member that was holding the left hand lower section in place.

As for the the frame mount holes, I ran a tap down them before even attempting a bolt as I thought the threads may have been chewed but they were very clean.

 

[Bendy toy]

Clean threads suggests the bolt fell out recently.
I've just checked mine. All ok, except the M6 crash bar mounts under the petrol tank, loose again.