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What is this thing called I need to find a new bolt for it.

Shefferan

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Sirius13!!
I’m getting frustrated because everything I try to search to find the bolt size is showing me the wrong stuff.
 

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I’m getting frustrated because everything I try to search to find the bolt size is showing me the wrong stuff.
I’m getting frustrated because everything I try to search to find the bolt size is showing me the wrong stuff.
I would call this a tachometer drive housing bolt. Have a look at "cmsnl.com" Take some time and I'm sure you will find this exact bolt on this web site. It has expandable parts diagrams. Could be an M5X25 (?) (I don't know the year of your bike.
 
I would call this a tachometer drive housing bolt. Have a look at "cmsnl.com" Take some time and I'm sure you will find this exact bolt on this web site. It has expandable parts diagrams. Could be an M5X25 (?) (I don't know the year of your bike.


Year is 1982 cb750c custom
 
It is the cable lock bolt for the tach drive. I think it is a 6mm x 1.0 pitch x 1" long
thank you

Also now it’s leaking from there and maybe from the head gasket in the same area too, hard to tell. Granted I still don’t have the proper screw for the cable lock bolt.
Bike is running thready and wants to die. Still drives just a pain to get carbs adjusted to where I want them. I am afraid of taking apart the engine and losing most of the summer doing it. Also have no idea what I’m doing. Any help?
 
So an oil leak in that area could be the tach drive seal or the valve cover gasket. The oil will travel during operation, so a way to trace the source is to clean the area and dust with Talcum Powder, then go for a ride. The oil will leave a track in the powder back to the source of the leak. Neither cause that I've mentioned is a difficult repair and doesn't require engine removal, etc.

We'll need more detailed explanation of symptoms to help with carbs
 
Thanks, I finally got a bolt for it temporarily until the right one comes in. Gonna see if that helps the leak. The bike is surging when running and dying when the clutch is pulled in(not every time). Then I adjusted the mixture screw on the carbs and it was idling perfect(after I made sure the throttle cable had enough slack) it was idling and running better but like ten min later I tried to start it and it was idling super low, way below where it was prior to shutting it down. I have no idea what’s happening.
 
Erratic, or surging, idle is often a sign of the carb throttle plates not in synchronization. It will also show if the bike is rev'd to ~3500rpm and when the throttle is released, the rpm does not fall right back down to idle rpm (1000rpm) but will hang and return slowly.

If you richened the fuel mix screws too much - beyond 3 to 3.5 turns - it may be a bit too rich and a lower idle speed will result.
 
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