CL77 bolt question

[305CL77Texas]

In my reassembly I have ned to repace some bolts
Example is a seat bolts listed in part manual as 8x40 but at hardware store I see codes like
m5 40 etc . I realize new labels have been establised how do I convert
Also not clear on thread pitch I know there is standard (1.50) and two fine threads (1.0 1.25)
but manual does not show pitch I think because all are 1.25 ????

example say part # CL77 90110-273-000 SEAT REAR MTG. BOLT (LATE) 8x40 to new lables

[e3steve]

The seat bolts -- for CB & CL, at least -- have extended, machined 14mm a/f heads to enable removal of the seat with the toolkit spanner (wrench).

Our bikes' screw threads for M6, M8 and, I believe, M10 are ISOmetric (International Standards Organisation); the pitch varies with screw size (Google <isometric fastener threads> for info).

The rest are JIS (Japanese Industry Standard), the pitch of which is still metric but, in most instances, marginally finer.

[davomoto]

The pitch for M6 is 1.0, M8 is 1.25, and M10 is 1.25 JIS.

Davo

[e3steve]

Thanks for the clarification, davo; so the only JIS threads that directly correspond with ISO are M6 & M8. I couldn't remember if it was M10- or M12-and-above that faded into the past (as well as JIS3, 4 & 5).

[davomoto]

As far as I know, yes. The axles and such may or my not correspond to ISO

Davo

[Snakeoil]

The seat bolts listed in the parts manual say 8X40. But the seat bolt for rubber mounted seats are a 40mm long shoulder bolt with the shoulder passing thru the rubber seat grommet/cushion. If your bike is a '67 you should have a rubber mounted seat. If you use standard harware store metric fasteners, you should make a sleeve to act as the shoulder to avoid crushing the seat grommet.
regards,
Rob