Mixture screws backing out issue

S

Spinnbait

New Member
I just finished rebuilding the carbs on my '81 CB750. It runs well for a bit, but the mixture screws back out and fall out after a few minutes of tuning. Is there some trick to keep them in place?
 
if you have the spring then the washer then the oring on the jet how the !@#$%^ is it backing out
 
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cxman said:
if you have the spring then the washer then the oring on the jet how the !@#$%^ is it backing out
Click to expand...

Your guess is as good as mine. 2.5 turns out and the little bastard backs out under vibration...

I was hoping there was a super secret squirrel Jedi trick that I was unaware of to solve this problem.

Enjoy the popcorn.
 
xb33bsa said:
or double-up on the o-rings ?
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Thanks! I'll head to the store tomorrow and source some o-rings. If that doesn't work then I'll hit it with a bit of red locktite. The engine temps will likely be too high for blue or green, but should keep the red at a reasonable viscosity for adjustment.
 
I was just thinking about the residual heat, but noted. I'll post my solution once discovered. Thanks for the advice.
 
that's a lot of vibration to loosen the screws if the springs are correct. I would be more worried about the vibes. Means the floats are shaking and wearing out the pivot pin.....Carbs are rubber mounted and should be vibrating that much...any other mods done?
 
Yeah - don't loctite them. Carbs will be junk if you do.


Something amiss with the springs. Either they need stretching or you don't have them in or....something. The screws shouldn't move of their own accord.
 
BTW - if you have it all correct and they still back out (for whatever reason), a smear of silicon over the screw heads should stop them moving. That way you can remove the silicon later on and re-adjust the mixture.
 
Thanks again! I'll stretch the springs and maybe find a slightly thicker o-ring. The silicon sounds like a good idea. It seems to be happy at 2.5 turns out so I may not have to worry about the silicon once set.

Only mods are a 4-1 and taped pods. It runs quite well until the screws back out, and even then it's not too bad.

It barely vibrates more than my M900 did, so that says a lot.
 
hillsy said:
BTW - if you have it all correct and they still back out (for whatever reason), a smear of silicon over the screw heads should stop them moving. That way you can remove the silicon later on and re-adjust the mixture.
Click to expand...

I'll second this.
 
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