Does anyone have a drawing/photo of what's at the bottom of the crankcase breather port on the K100 2V engine? I may have dropped a screw into the crankcase breather port while replacing the "Z" tube and I'm wondering how deep into the engine it could fall. I've looked down the crankcase breather port but can't see it.

Yes.......back soon   just have to get onto the compiter

Thanks Charlie.

in two parts , as i have the bell housing off Gerty at the moment 

thats a bad issue , because just below the breather tube is the intermediate gear that runs off the starter , then meshes with the sprag clutch .
however the screw may have lodged in a section just below the breather port on the bell housing side

i supose a magnetic pick up tool will have some issues in as much as the idler - intermediate gear is also steel but you may get lucky ? if you come from the breather tube ,  but perhaps could be lucky if you go in the starter port ?

likely the screw has gone all the way to the bottom of that housing ,,,,,  with luck ?


pic 1 engine side 




pic 2 bell housing side starter gear removed




pic 3 bell housing side with gear installed 




hope it helps , and good luck

Awesome, thanks Charlie. Just bought a cheap inspection camera from Bunnings so I'll try going in through the breather port.

Would taking the sump off allow access?

I would get a tiny rare earth magnet with a hole in it and tie it onto some fishing line. Then drop it down the hole to see if it will grab the screw and then carefully extract it

Like this 8x3:

https://www.aliexpress.us/item/3256803926580811.html

Nope      sorry to say.

That v shape is the limits of sump or internal engine and the clutch housing

Dropping the magnet on fishing line will just have it stick itself to the first piece of ferrous metal it comes near.  It will never get to the screw if it's more than a half inch down the hole.

Point-Seven-five wrote:Dropping the magnet on fishing line will just have it stick itself to the first piece of ferrous metal it comes near.  It will never get to the screw if it's more than a half inch down the hole.

True. Maybe put it on the end of some solid copper wire so that you can bend the wire and direct it. (Like a piece of Romex.)

Found! The screw was in behind the throttle body for cylinder 4 and not easy to spot.
Thanks for the responses/suggestions.

Nice   find

Yes, huge relief when i saw it.