Bolt size for stalk mirror mount

[TeddyG]

I've got a 74 750SF w/ a Brembo brake lever housing and I want to add a traditional screw in stalk mirror. I'm not sure what thread pitch the 10mm threading is, so before I order a mirror, can anyone verify this? I've tested w/ 2 different- 10mm bolts but they don't fit and I don't want to force it and ruin the threading. I'll probably use a tap since the threads have paint on them and appears to never have been used.
Most stalk mirrors are 10mm x 1.25.
Thank you

 

[The Sock]

The thread in the Brembo master cylinder is, I believe, 10 x 1.5.
Choices are tap it to 1.25, make an adapter 1.5 male/1.25 female allowing stock mirrors to be used, or get a long stem 1.5 mirror cut off the existing threaded section and with a 1.25 die cut a new thread.

 

[TeddyG]

Thanks- I bought a 10mmx1.25 test bolt and it fits

 

[Paul Marx]

The thread in the Brembo master cylinder is, I believe, 10 x 1.5.
Choices are tap it to 1.25, make an adapter 1.5 male/1.25 female allowing stock mirrors to be used, or get a long stem 1.5 mirror cut off the existing threaded section and with a 1.25 die cut a new thread.

10 x 1.5 is a pretty common screw.
Paul

 

[The Sock]

10 x 1.5 is a pretty common screw.
Paul

Not on stalk mirrors, Paul.

 

[Paul Marx]

Not on stalk mirrors, Paul.

You're right.
But since all I see with stalk mirrors are my elbows, on all my Laverda, I have extensions that screw into the mirror mount and into which you fix the stalk. It pushes the mirror out 5cm or so.
Paul