Vacuum screws

[Pauarc]

Does anyone know what size the vacuum screw on carb on cb750k are  like to change them they are a bit damaged

[Trigger]

Does anyone know what size the vacuum screw on carb on cb750k are  like to change them they are a bit damaged

M5 with a 5mm thread 

[Pauarc]

Thanks Trigger

[Trigger]

Thanks Trigger

You can use brass cheesehead screws but, hard to find in a 5mm thread length so you have to cut them down. The sealing alloy washers are 4.9mm which bloody expensive for a sealing washer   

[sprinta]

These may be of use to somebody who is not bothered with originality and would like the ability to just push on the vacuum gauge hoses without having to remove the screws and then fit the extensions as they can be left in place?

https://www.ebay.co.uk/itm/134331731567

[Laverdaroo]

Does anyone know what size the vacuum screw on carb on cb750k are  like to change them they are a bit damaged

M5 with a 5mm thread 

Not entirely correct that….

Surely if it’s an M5 bolt, it’s telling you it’s 5mm, the pitch of the thread is what your after in that question in which case it’s only one of two options .08 or .09, that’s all it can be. Not in the workshop so can’t check but if you have a tap and Dye set use your thread gauge and find the matching pitch in that particular screw. Simples




Sent from my iPhone using Tapatalk

[Matt_Harrington]

Roo, I think he means 5mm long....

[Trigger]

Does anyone know what size the vacuum screw on carb on cb750k are  like to change them they are a bit damaged

M5 with a 5mm thread 

Not entirely correct that….

Surely if it’s an M5 bolt, it’s telling you it’s 5mm, the pitch of the thread is what your after in that question in which case it’s only one of two options .08 or .09, that’s all it can be. Not in the workshop so can’t check but if you have a tap and Dye set use your thread gauge and find the matching pitch in that particular screw. Simples




Sent from my iPhone using Tapatalk

The Question was: What size the vacuum screw; and the bolt is M5 with a 5mm thread length. He never asked the pitch but, it is JIS standard 0.8 

[Oddjob]

If that's the case he should have written it M5x5mm. Thread refers to pitch not length, especially as there are screws and set screws. It's an 0.8 pitch BTW which is vital to know if your not replacing like for like as in using stainless ones instead.

[Trigger]

And there are copper screws which the 750K has. 

[Pauarc]

Thanks everyone check with gauge they are .8 this may help someone

[Matt_Harrington]

Interesting stuff - thanks for posting.

[Laverdaroo]

Sent from my iPhone using Tapatalk

[Oddjob]

He never asked the pitch but, it is JIS standard 0.8 

According to that chart from Honda that information would appear to be wrong, ISO is standard at 0.8, JIS standard would be 0.9. 

[Trigger]

I have been in the Honda business more than 20 years and must of handled and sold more than a million JIS screws and the M5 standard pitch is 0.8.


[ Guests cannot view attachments ]


Hard to get a good picture


[ Guests cannot view attachments ]