Topic: 76 cb550f project

[firebane]

Do you have all of the mixture screws all set 1 1/2 turns out?  Did you clean all the pilot jets really well?

Yeah everything cleaned well x3.

What I found today was the throttle cam was out of alignment so I fixed that then found the stop screw not used so I adjusted everything so the slides bottom are just visible in the opening of the carb.

I was also able to get the bike to idle at 1100 for a bit before it went pop pop then died.

[firebane]

So I am at a complete loss. I rebenched the carbs as a I realized I did them wrong the first time.

I have adjusted the valves, reset the base timing and replaced the o-rings for the intake  manifolds.

No matter what I do the bike wants to idle around 2500-3000 rpm.

Could this be something with a plugged jet or something in the carb? What I don't understand is that as it runs it pop pops and to me this is a lean condition.

Maybe I need to adjust the needles? Or maybe my aux tank is feeding the bike to much fuel? I do notice when taking off the carbs the inside of the bouts are wet.

[754]

Do they look like they close when you back the idle speed screw off ?

[firebane]

Do they look like they close when you back the idle speed screw off ?

Slides? Yup completely close when idle screw is backed off.

[calj737]

And you bench synched the carbs to 1/8" gap? If so, you have now confirmed that you have no vacuum leaks either?
And confirm the throttle linkage/cables are returning fully when you let go. It is not uncommon for the throttle to become bound against the grip and not shut. Likewise, the pull/push cable linkage can be preventing the slides from dropping fully.

[firebane]

And you bench synched the carbs to 1/8" gap? If so, you have now confirmed that you have no vacuum leaks either?
And confirm the throttle linkage/cables are returning fully when you let go. It is not uncommon for the throttle to become bound against the grip and not shut. Likewise, the pull/push cable linkage can be preventing the slides from dropping fully.

Set to 1/8" gap yes
Cables are new and linkage is free
Rubber boots have no cracks and clamps are tight but have not confirmed air leaks.

Remember I have gone from a bike that wouldn't run without starting fluid to a bike that now runs at 3k

Couple more things I found tonight... Plugs are heavily fouled black meaning running really rich but the other thing is pipes are not consistent with temps either.

[calj737]

Ok, so I re-read the entire thread here. You say you had the carbs apart and cleaned them well 3 times. But you never indicate what size jets, or needle positions. You posted earlier that the plugs were badly fouled, but haven't yet shown plugs since cleaning them up.

Even if the jets are stamped with the correct numbers, its possible the PO drilled them out, or re-jetted using non-stock brand/sizes. Given the torment that bike has seen in its life, I would have the carbs FULLY disassembled and cleaned. Since it used to require Starter Fluid to run, that tells me they are wicked clogged up. Now the bike won't idle below 2k, so there's a strong indication of improper fuel metering.

Can you provide the carb stamping number (right side of #4) so all adjustment advice is relevant to your carbs.

[firebane]

Ok, so I re-read the entire thread here. You say you had the carbs apart and cleaned them well 3 times. But you never indicate what size jets, or needle positions. You posted earlier that the plugs were badly fouled, but haven't yet shown plugs since cleaning them up.

Even if the jets are stamped with the correct numbers, its possible the PO drilled them out, or re-jetted using non-stock brand/sizes. Given the torment that bike has seen in its life, I would have the carbs FULLY disassembled and cleaned. Since it used to require Starter Fluid to run, that tells me they are wicked clogged up. Now the bike won't idle below 2k, so there's a strong indication of improper fuel metering.

Can you provide the carb stamping number (right side of #4) so all adjustment advice is relevant to your carbs.

I will be pulling carbs again today and doing a heavy once over of all things. I don't believe anything has been drilled or modified by the PO and the carbs are the 069a for the 550f

[Stev-o]

 I don't believe...

You are leaving room for doubt.  When properly trying to diagnose an issue, cannot overlook anything. 

[firebane]

So I pulled everything todat and everything is fine and stock. Needle clip was up 1 so put that back in the middle.

Before putting the carbs back on decided to do cam chain and well #$%*.

Basically this http://forums.sohc4.net/index.php?topic=87205.0

No matter what I can not undo the nut which from reading means the tensioner is hosed

[calj737]

So I pulled everything todat and everything is fine and stock. Needle clip was up 1 so put that back in the middle.

These 2 sentences disagree with each other. 
How did you confirm the jets were stock and unmodified? Did you remove the pilot jets and clean the emulsion tubes?

[firebane]

So I pulled everything todat and everything is fine and stock. Needle clip was up 1 so put that back in the middle.

These 2 sentences disagree with each other. 
How did you confirm the jets were stock and unmodified? Did you remove the pilot jets and clean the emulsion tubes?

Apologies. I when I did the cleaning in the winter I probably moved them so dropped them back to middle position. Going through again I did find the emulsion tube on #1 was missed so cleaned that up.

I also think I may not have had the carbs on all the way as I found they would go on further to the point the carb bracket would touch the boot.

I also found that in fact my aux tank does flow slower or faster depending on how far you open it so I won't open it as far in hopes to not flow faster than the bike needs.

[NobleHops]

Open it all the way. The float needle valves manage the supply to the bowls.