I'm not a carb guy, so thanks for all the info you can send my way. The diaphragms looked good, but maybe the vacuum is not good. Any connections or hoses to look at? I'll double check that the covers over the diaphragms are in place correctly. I was also going to check to see if they were sliding OK. That may be a more likely source of the issue than the jets.

Anything else? I'm hoping to make time to look at them this weekend.

 

You said your bike is a Cali model. Any of the smog stuff removed? There are a few vacuum lines that need to be set up correctly or plugged. Does yours have the purge valve still on? I had one go bad and was a slight vac leak, but it made the idle erratic.

You mentioned that one of the idle screw needles was fouled. Did you totally disassemble the carb bank and clean each carb individually or as a group. I'm still leaning towards a plugged idle circuit or two. When you cleaned the carbs did you blow all of the jet orifices out with compressed air?

The cold start symptoms also sound like your choke cable/actuator bar is not setup quite right. If you look at it under the airbox, you will see a groove in the metal ferrule that is clamped down with a screw. This is normally the setup point. But, the cable stretches over time and you have to move the ferrule back in order to get the bar to pull the actuators on the carbs far enough. This will improve cold starting a bunch.

Keep at it.

 

Thanks for posting and keeping it going.

Lets see, first I kept the carbs together and did use compressed air oneverything I could find. I'm thinking the same thing, that there is at least a partial plug somewhere.

All the vacuum lines are going somewhere LOL, I tried to follow the diagram on the air box lid. Yes, the purge valve is still there, but I am not confident that it is OK. Can a bad one disrupt the vacuum system and cause the needle jet problems? Is removing it just pluggingthe lines?

I was going to review the choke cable, I did reattach it but did not see if it actually worked. That was going to be on the list, but thanks for pointing out cable stretch because I did not think about it.

I’m hoping to have time tonight to get some work done on it…

 

You can plug the line leading to it and cap the port on the valve. Vacuum on the valve allows fumes in the cannister to be drawn into the intakes to be burnt. If the valve leaks it it like any uncapped vacuum port. The bike would idle poorly and struggle throughout the rev range. It wouldn't normally cause problems in the 3000 to 5000 rpm range like you're experiencing.

 

OK, got some work done tonight. The issues I have seen so far are: Two of the needles were not moving freely, they were sticking. One stuck fully open when I moved it and would not return. One of the needle jets I did not get fully open, when I sprayed carb cleaner in it nothing came out the other side. Funny thing is that is not the carb that had the fouled needle. Next, I over looked the chokes, aka the fuel enrichment valves. Most were sticky and one had to be forced open. I guess there was so much play in the cable that I assumed they were working. Lastly, two screws were a little loose on the diaphragm cover.

So, letting it sit over night with some carb cleaner. Will hit it again tomorrow and hit it with compressed air again. I did some more cleaning on the needles and they move freely now. The choke valves move freely as well. I also reset the pilot screws to 2 1/4 turn, high altitude has a different setting and I'm in Denver...

The choke definitely explains the cold behavior. And the clogged jet and sticky needles could explain the stumble when I hit the throttle fast.

What about the air control valve? Probably have the wrong name of the part, the vacuum diagram says AVCV. And thats about all I can find, it definitely is part of the emissions. Could some one point me towards the instructions for removing it? I can't seem to google as well as not being able to clean carbs...

 

After describing the problems you corrected, I don't think your AVCV valve is an issue, but...
There should be a vac line diagram on the top of your airbox. The AVCV valve gets it's vacuum from the fitting on no. 1 cylinder that goes to vac petcock too. The valve controls fumes it get from the two vents between the carbs. When the motor runs it opens the valve to let air in and goes to a t-fitting between the PCV that opens and sucks fumes out of the cannister under the bike. So,... You need to vent the carbs, cap off any open vacuum ports, isolate the valves, and try it.

Running your smog stuff on the street isn't an issue other than it looks complicated and it makes it difficult to get your hands in there.

 

303 - Were you able to get everything running properly?

I let my '94 F2 sit for 3 years and I'm also having what I think are fuel delivery issues. I'm looking through the tech forum trying to find threads about similar issues.