Another full choke runner

[eluwak]

I have a sort of similar problem to RHHarrison in this post. I have a '90 GL1500SE that just recently came into my possession that has been sitting a few years. I could hear it kicking over and was able to adjust the idle knob until it would idle. It has a new fuel filter and a tank full of fresh gas that I dumped the better part of a can of seafoam into. The petcock was leaking fuel, so I rebuilt it and made sure it was working properly. The vacuum pressure to the petcock seems to be good at 500+ mmHg, and fuel does flow out. I've been starting it up and letting it idle for 20-30 minutes at a time slowly backing off the choke, but I just can't seem to get it past 15-20% up before it dies. Increasing the throttle also causes it to die.

My next guess/step is to yank the cabs and have them cleaned/rebuilt, but I have a question. I noticed that when I back off the choke to the point of the bike dying, and then reapply it, that it seems that there is a whoosh of vacuum release tied to that action. Is that consistent with anything or normal?

[RockportDave]

Welcome to the forum.
The choke is really an enrichment that allows more fuel into the carb.
If it sat a while it probably needs a carb rebuild and possibly vacuum lines replaced.
Mine had sat a lot of its life before we got it and it had a rough idle and lack of power. I finally pulled the carbs (3rd time), soaked them in carb dip, installed new jets, o rings, accelerator pump kit and new carb isolators. Balanced the carbs and did the idle drop. It runs great now. I also checked all the vacuum lines while in there and found one with a hole.
I wanted it to be dependable so I spent the money and time to do it right.
Dave

[eluwak]

So I finally got the carbs off the bike yesterday to try to rebuild them. The vacuum lines are not looking the greatest, and I want to just replace as many as I can while the carbs are off. I am finding some difficulty locating the correct size hoses to order...

Does anyone know where I can find these on the diagrams in Partzilla? I saw WingAdmin over here showing three sizes (3.2/4.2/5.8 mm). where's the best place to find these as amazon seems a bit limited?

[bellboy40]

Try these links and see if you can find what you are looking for.

https://www.partzilla.com/catalog/honda ... e/tubing-1

https://www.partzilla.com/catalog/honda ... e/tubing-2

[ct1500]

I noticed that when I back off the choke to the point of the bike dying, and then reapply it, that it seems that there is a whoosh of vacuum release tied to that action. Is that consistent with anything or normal?

Not a vacuum release. A carburetor controls RPM for a given load by the amount of throttle plate opening metering air/fuel mix into the engine. At a closed throttle idle an enrichment system needs to also add air to enable an increase in RPM.

The enrichment system adds fuel AND air via a dedicated carb circuit. The intake of this air is a port at the top of carb. The whoosh sound is simply the air making its way through this labyrinth into the engine and is normal.