Vacuum tune cb360 issue

[keeleydavis]

I am trying to sync my carbs on a 75cb360 and have a 4 gauge vacuum emgo tuner. Imbusing just the first two gauges.I can't seem to get the first carb to sync with the second. I wants me to turn the screw way further counter clockwise than the screw will go. Is this something to do with the air screws? The screw stopped turning and I don't want to force it if it's at the end of the line. Any thoughts?is it also odd that the gauge needles go the opposite direction when I gas it?

 

[mydlyfkryzis]

Maybe you have the adjustment screw the wrong end of the travel? Or you may have a vacuum leak.

But the vacuum should go the same way when opening the throttle. Not sure how you got that to happen...

 

[keeleydavis]

So I tried syncing the carbs again again and it looks like I just cant turn the adjustment screw out anymore. The pic below is as far as I can get them synced. The left muffler pops also when i decel, Would getting the carbs in closer sync take care of that pop? I just adjusted the timing points also. Any thoughts?

 

[mydlyfkryzis]

The picture show the left gauge (Assuming left carb) is shut all the way, and the right is doing all the work. Did you try going the other way on the adjustment screw?

Are you adjusting the correct screw? Is the screw assembled right. There are two washers on that screw, the linkage for the left carb should be sandwiched between the washers.

 

[keeleydavis]

The picture show the left gauge (Assuming left carb) is shut all the way, and the right is doing all the work. Did you try going the other way on the adjustment screw?

Are you adjusting the correct screw? Is the screw assembled right. There are two washers on that screw, the linkage for the left carb should be sandwiched between the washers.

Thanks for the feedback. Yes i did turn it the other way and the left hand needle would go further to the right. The weird thing is when I feel the pressure coming out of the two mufflers, they feel almost the same.

When you say there are two washers do you mean there is another locknut on the underside of the screw? How would you get to that one if there was? It would make sense why I can only turn it but so far out.

 

[mydlyfkryzis]

Look at the attached picture. you will need to remove the carbs from the bike, loosen them from the bracket. The sybc screw has a spring and 2 washers. The u-shaped bracket of the left carb needs to be placed between the 2 washers. the attached photo shows it wrong, but is the only detail I have. You can see the 2 washers on the left side of the bracket. The u bracjet needs to go between them.

FYI: I "borrowed" this pic from CrazyPJ's earlier post on the same subject

 

[crazypj]

I've just finished a set of carbs with similar problem, couldn't get left side to go anywhere other than 15~20 on gauges even though right side would go from 10~60
Got them set perfect, as long as lock nut wasn't tight
Ended up fitting a different throttle shaft and de-burring the throttle plate, (it couldn't completely close even though you couldn't see light until throttle was cracked open)
Initially the throttle plate wasn't properly centered in bore
almost got me tearing my hair out (been 'playing' with these carbs for couple of weeks)
They will probably get mailed back tomorrow ;D 8)

 

[keeleydavis]

I've just finished a set of carbs with similar problem, couldn't get left side to go anywhere other than 15~20 on gauges even though right side would go from 10~60
Got them set perfect, as long as lock nut wasn't tight
Ended up fitting a different throttle shaft and de-burring the throttle plate, (it couldn't completely close even though you couldn't see light until throttle was cracked open)
Initially the throttle plate wasn't properly centered in bore
almost got me tearing my hair out (been 'playing' with these carbs for couple of weeks)
They will probably get mailed back tomorrow ;D 8)

Hmm. I think you have my answer crazypj but Im not entirely sure I am following you. So what did you do to fix the issue again? What is de-burring and also unclear as to what centered in bore means. Sorry to make you dumb down an answer that is probably already perfect. Im still new to the game Also what would cause this issue? Did it have something to do with me messing with the carbs in the first place?

 

[crazypj]

The throttle plate should pretty much seal off the carb bore when fully closed but if the screws were tightened before centering it only contacts top or bottom
I didn't notice the burrs on edge until I took throttle plate completely out, used a real fine needle file to remove them.
I'll post pictures sometime but not this evening

 

[keeleydavis]

The throttle plate should pretty much seal off the carb bore when fully closed but if the screws were tightened before centering it only contacts top or bottom
I didn't notice the burrs on edge until I took throttle plate completely out, used a real fine needle file to remove them.
I'll post pictures sometime but not this evening

Yeah I think the photo would help me out for sure. Looking forward to seeing it. Thanks much.

 

[keeleydavis]

I am correct in thinking that turning the screw counter clockwise will turn up the throttle of the left carb?