'80 SG... First Start...

[DGXSER]

Have you set the petcocks to prime? If the float valves are stuck in any way, you will get fuel out the airbox.

[crazy steve]

I ditched the octy and blocked off the 'prime' in the petcock, so yes, if the petcocks are on I've got fuel flow...

But that's the odd part; I didn't get any fuel out of the airbox, and I looked. Now, I did use the brass jet needles out of the rebuild kits (c-clip in the middle groove), but they're a bit shorter and definitely blunter than the OEM needles. That's the only variation from stock, so maybe I'll swap those out too and see if that helps.

[DGXSER]

If the needle is different in the same emulsion tube, then it could/would change the fuel mix. That could very easily be the problem. Again, you may have 81 carbs instead of 80 carbs there.

Did the original needles have an adjustment for height? I know the 81 models do not.

[crazy steve]

If the needle is different in the same emulsion tube, then it could/would change the fuel mix. That could very easily be the problem. Again, you may have 81 carbs instead of 80 carbs there.

Did the original needles have an adjustment for height? I know the 81 models do not.

I asked about the needle jets, and got a reply from James who used those that they were no problem. And they were touted as an 'improvement' over OEM in the eBay listing because they are adjustable, while OEM supposedly isn't (mine aren't).

[crazy steve]

Ok, a possibly bone-headed question....

Pulled the carbs, and I still don't see anything wrong. I even flipped the carbs upside down with the bowls off and checked for fuel flow; there is none.

BUT, I also noticed that the float valves have tiny spring-loaded pins in their centers; if you press on the float tang, it will drop the floats another .1" at least. So, do you press down on these while adjusting the float level? If these springs allow any fuel past as the floats come up, the float level was hopelessly rich (which would explain everything). Possible causes could be vibration or just the way it works....

Push on these for adjustment, or not? Or just remove them? The manual makes no mention of any spring-loaded plunger...

[bikerphil]

Ok, a possibly bone-headed question....

Pulled the carbs, and I still don't see anything wrong. I even flipped the carbs upside down with the bowls off and checked for fuel flow; there is none.

BUT, I also noticed that the float valves have tiny spring-loaded pins in their centers; if you press on the float tang, it will drop the floats another .1" at least. So, do you press down on these while adjusting the float level? If these springs allow any fuel past as the floats come up, the float level was hopelessly rich (which would explain everything). Possible causes could be vibration or just the way it works....

Push on these for adjustment, or not? Or just remove them? The manual makes no mention of any spring-loaded plunger...

No, don't push them down. Whatever weight the float supplies pushing the pins down, that is where they are to be measured. I would also use the original diaphram needles as long as they are in good shape. These carbs (early and late) run best with no modifications made to them other than main and pilot jet sizes, JMHO.

[crazy steve]

Well, let me ask this; do those plastic floats get 'fuel logged' over time? These are undoubtably original floats....

[petejw]

hi steve,
phil's got u covered there, also the spring in the plunger should be strong
enuff to hold the weight of the float without compressing.

with the 80 model carbs u have did they come stock with the plastic
floats or did u swap them out from the brass ones?

if all 4 plugs are wet and running rich there must be something in common
with all 4 carbs causing the rich condition, are the pilots stock? or aftermarket items? air jets stock?
theyre not the carbs that have the crossover and need the pilots plugged, just throwing some things out there.


sorry just reread ur first post, most of the answers were there.

[petejw]

Well, let me ask this; do those plastic floats get 'fuel logged' over time? These are undoubtably original floats....

not that ive ever seen or heard of.

[petejw]

are the float bowls the same as the 81 model where
u could attach a hose to it to check the float heights
while the carbs are in situ?

[crazy steve]

Yep, that's the type of bowls I have, so I guess my project for tomorrow will be to check float levels ala the '81 method with the hoses. I suspect that the floats aren't floating as good as they should, as that's about the only thing I can see that could be the problem. Now that I think about it, when I was adjusting the float levels I was surprised by how high they had been apparently set as I had to lower every one, and by a bunch....

[petejw]

if u have the carbs off the bike still u could
stick them in some water or fuel and see if they float
that way.

"when I was adjusting the float levels I was surprised by how high they had been apparently set as I had to lower every one, and by a bunch.... "

was that after u replaced the needles with new ones?
have u looked at the old ones and compared that there the same?

what if u put an old needle and float in 1 carb and compare the heights with a new needle and float in the next carb?

[crazy steve]

...was that after u replaced the needles with new ones?
have u looked at the old ones and compared that there the same?

Pete, the carbs were already partially disassembled and some stuff was gone, the float valves in particular...

Although the new ones look just like the ones I found in some other '80-81 style carbs I have.

[petejw]

no worries,
just throwing sum thoughts out there
and have nothing better to do atm.

[bikerphil]

Steve, you're 100% sure no crossover passage, otherwise you need the rubber plugs. You are running 120 or smaller mains and 42.5 pilot and 185 air, correct? The height of the needle/seat should not matter as long as the float height is somewhere in the 23MM range.