Topic: Sync Screw question

[ct_bobber]

Hi all,

I just got my first 75's CB750 bobber style.  I'm currently getting the bike ready for the summer.  I was looking around the carbs and found that one of Sync screw is missing.  However, the previous owner has put regular screw to cover it.  My question is, is it crucial to use the oem sync screw or is it okay to just any screw as long as it block the air going in and coming out.

I appreciate your responses.

thank you in advance.

[Bodi]

Just plugs the hole, any screw with the same thread is good. I would avoid having a lot of screw sticking out on the inside though. I put in allen head screws just because they don't fall off the driver.

[ct_bobber]

Thank you much.

[Johnie]

On my OEM carbs there is also a thin seal type washer behind that screw. Not sure if that is there to help prevent a vacuum leak or just for the screw.

[lucky]

I have no idea what you are talking about.

Tell us the year of the bike at least.

When you sync the carbs you are adjusting the IDLE screws.

The mixture screws should NOT be turned when you sync the carbs.
Just set the mixture screws all exactly the same. Forget that lean best idle business.
The most important thing is that they are all set the same, and all of the mixture screws are in good condition including the O ring and washer if it has them.

No holes should just be plugged with a screw.
We need a photo on this.

[Johnie]

Lucky...my thought was he is talking about the vacuum port screw.

[extek66]

if you are talking about the vacuum port it is a 5mm thread.just get short stainless allen heads cut gaskets out of gasket material available at auto zone work great easy to install and remove

[lucky]

Lucky...my thought was he is talking about the vacuum port screw.

Thanks Johnie, I was just not sure.
Without a screw to pug the vacuum leak it would not run very well at all and could burn a piston up.