Honda CX 500 Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
Hello clever fellows.
Any one by chance know what sort of thread is on the M12 cylinder heads bolts? What's the pitch as I think there are 3 possibilities. I've a rather bodged helical insert that needs changed, I'm guessing it's a shack proof helicoil that's chewing bolt threads. I've got some nice new replacement bolts and don't want to chew anymore up. I'll look closer tonight to confirm the helicoil.
Appreciate your help.... I'm a newbie to the forum.
 

·
Registered
Joined
·
4 Posts
Discussion Starter #3
I've locked my shed for the night but if you don't get an answer by morning I'll put a pitch gauge on one.

I think it's 1.25 mm but I'll check.
Oh that's brilliant. Thank you. Catch up with you tomorrow. I've a load of tools but no pitch gauge.
 

·
Registered
Joined
·
53 Posts
If you have a tape measure and can count, then you can determine the thread pitch.

1.25 pitch = 1.25 threads per millimeter.

Use your measure, count the threads in 4 millimeters, if you have 5 thread, then the pitch is 1.25.

Can't use this method in a female thread, but with the bolt in hand the task is easy.
 

·
Registered
Joined
·
5 Posts
Thing is Newt I think 3 of the possible pitches are 1.25...1.5...1.75
I'd like to be sure before I screw the tread up. But yes your right ....I guess with a bit of maths I could work it out. Too late for me to think it straight now. Job for the morning. Be interesting if my maths work out the same as CXPHREAK pitch gauge. Gives a nice warm feeling you know it's got to be right.....Either that or I've got Menopause as well as poor eye sight.
 

·
Registered
Joined
·
53 Posts
True.

If the pitch is 1.5, then in 6 mm the thread count would be 4.
If neither 5 or 4 threads appear in the measure, then by elimination the pitch would be 1.75.

When Plan A isn't available, then Plan B can be a viable path.
 

·
Registered
Joined
·
5 Posts
Your all stars. Brilliant. Thanks for the time and effort. Really appreciated. Next pay day a small split ball gauge and a Pitch Gauge on the shopping list. Got my cylinder heads in the shop having valve seats recut so they come first.
Thank you.
 
1 - 9 of 9 Posts
Top