New member - Montana

Okay so after fully cleaning the carbs again and just setting the slides just with the wire, i got them thrown back onto the bike and fired up.  Still runs at full choke but i can take the choke off and it stays running just kind of stumbles and if given slow throttle i can rev it to alittle higher than 2500 rpm before it begans to die.  At 1/4 choke it runs great and when given throttle actually revs and sounds like a bike.  So i believe now I need to get the gauges to actually sync the carbs correctly, does this sound like similiar symptoms of unsynced carbs now? or am i possibly still fighting something else?

If it will rev on 1/4 choke it appears the fuel supply is OK which would suggest an "air leak" between the carbs and head

Progress. So if it only runs on quarter choke then the carbs are running lean. Too much air in the mix. Fully seat the air mixture screws  gently at the intake side of each carb. Now open them a full turn. Anywhere between a turn and two or so out is normal. Try a quarter turn at a time from there. Let the engine warm up. With the right mixture your plugs shouldnt be wet or sooty after running without choke. Hope this is usefull 

Re. Synchronization. With the sliders all touching the wire thats roughly it. Vacuum gauges later just iron out little roughnesses between carbs but get it to tick over first.

I'll check for air leaks between head and carbs, is there any good way to do this? Or just by feel and guess. And my carbs do not have the air mixture screw on the sides only the fuel mixture on the bottom. Would adjusting that help by giving it more fuel?

There's a good chance the rubber carb holders (between carbs and the cylinder head) are over 40 years old and brittle (mine were). There's no real good way to test them (spraying carb cleaner around them while running may not pick up air leaks).  A set of new ones will ensure no leaks, just don't buy cheap chinese.  Z1 enterprises has good quality ones for a reasonable price.

Hi best way to check for air leaks is squirt easy start or carb cleaner onto the rubbers while its running and if theres a leak the engine note will change. I have no experience of your mixrure screws but a small adjustment either in or out wouldnt harm anything but note the original settings so you can put them back the way they were if needed

Originalretro wrote:

Hi best way to check for air leaks is squirt easy start or carb cleaner onto the rubbers while its running and if theres a leak the engine note will change. I have no experience of your mixrure screws but a small adjustment either in or out wouldnt harm anything but note the original settings so you can put them back the way they were if needed

This method of spraying easy start doesn't always highlight leaks, however if the manifolds are original it's pretty much a given that they are overdue replacement

Its always worked for me, any cracks surely will suck in and alter the engine note, also to buy a new set of rubbers before pinpointing that they are even necessary seems wasteful to me.

Originalretro wrote:

Its always worked for me, any cracks surely will suck in and alter the engine note, also to buy a new set of rubbers before pinpointing that they are even necessary seems wasteful to me.

A significant leak, yes absolutely it works but multiple smaller leaks not so much (unless you have access to an exhaust analyser and catch watch the Hc reading spike even if you don't hear a change) these are a known point of failure any many guys on here have spent way more in dollars and time messing with jetting and multiple carb strips to no avail. Changing them is a matter of choice as with any other part that degrades over time. Sometimes without access to thousands of dollars worth of diagnostic equipment it's not possible to pinpoint certain faults and you are best to rely on the knowledge and experience of others.(IMHO)

Originalretro wrote:

It’s always worked for me, any cracks surely will suck in and alter the engine note, also to buy a new set of rubbers before pinpointing that they are even necessary seems wasteful to me.

Agree with everything so far. No body has mentioned float levels. That will cause the lean condition. Float level needs to be set and verified. I agree with Wookie, buy new carb holder boots. It’s a sound investment that will serve you well for years. Again as mentioned the fuel type pilot adjusters very susceptible to breaking the tips off and sticking in the passage. I’d pull them out and post pictures so we can see if they are intact.

See photo bottom right
 

Here is the procedure for setting float levels. 
 



Lots more needs to be checked off the list also. One critical before moving on is coil primary voltage. 

I have not messed with the float level so ill have to get the tool to check that.  As far as the pilot screws i know are good and can adjust them as when i cleaned the carbs the tips are all nice and pointed, i talked to the previous owner and found out the carb to head boots were replaced when he first got it so fairly new and not original but doesnt mean they cant be bad but havent been able to double check.  But now onto the real issue is that i wont be able to really do to much for a bit because it winters coming early up here and just got a nice blanket of snow and ice.  i dont have a garage and my shed is full but i was able to ride it about 3 blocks down to my sister's and her fiance's house and put in their garage.  I can work on it there when its a bit warmer out or when i get a heater just because its not a heated garage.  I will continue to research more on the bike and gather parts so hopefully when we see the warmth again without the white stuff i can have it basically ready to ride.