2f Carb Tuning - Timing - and Vacuum Routing for Desmog (1 Viewer)

[g-man]

You can look at the image of mine to get and idea of how far to mount it. Good idea to insulate the wires. See the white wire cover?

 

[g-man]

So why did the truck rpm's increase at the light? Make sure you check the vacuum hose that runs under the air cleaner from dizzy to advancer port on the carb. Does the inboard side of your carb look like this?

 

[dannyvp]

So why did the truck rpm's increase at the light? Make sure you check the vacuum hose that runs under the air cleaner from dizzy to advancer port on the carb. Does the inboard side of your carb look like this?
View attachment 2044144

Great question.
But no by carb does not look like that. A Fuji / city racer carb only has one port on that back side. Remember it’s desmogged.

 

[g-man]

hmmm? does in come with instructions on hooking it to the dizzy?

 

[dannyvp]

hmmm? does in come with instructions on hooking it to the dizzy?

No instructions. Just a video emailed on the otramm lean drop method of tuning.

 

[g-man]

An open vacuum port, A loose connection. You'll figure it out. Go back to trying to run it at idle with the choke off. Use process of elimination to find it. Good news is your compression figures are good and you have a good engine.

 

[dannyvp]

An open vacuum port, A loose connection. You'll figure it out. Go back to trying to run it at idle with the choke off. Use process of elimination to find it. Good news is your compression figures are good and you have a good engine.

Yea I just need to find where the choke screw needs to be set at.

 

[g-man]

Images may help here. What are you calling the "choke screw"?

 

[NeverGiveUpYota]

I found this in a box. It doesn’t happen to be a temp sensor does it? It’s pretty small, think quarter sized.
View attachment 2044105

Cut it off the pipe. Use two bolts to add it to the two threaded holes on the intake. The cable will need to be attached to that tiny threaded end. To wire it, you’ll need a piece of bicycle cable, choke cable (I replaced mine so used the junk one), or some sort of insulated cable. Regular wire will fry pretty quick after a few cycles.
If you want pixs lmk.

 

[NeverGiveUpYota]

Yea I just need to find where the choke screw needs to be set at.

Furthest screw out on the facing right of the carb. Pull the choke handle and get the RPMs to 1800. That’s it.

 

[NeverGiveUpYota]

No instructions. Just a video emailed on the otramm lean drop method of tuning.

You followed the directions in my city racer thread right regarding the vacuum lines and a tee or two?

 

[NeverGiveUpYota]

So why did the truck rpm's increase at the light? Make sure you check the vacuum hose that runs under the air cleaner from dizzy to advancer port on the carb. Does the inboard side of your carb look like this?
View attachment 2044144

G, unless you have a City Racer carb, stop posting info that is no help to Danny.

 

[dannyvp]

You followed the directions in my city racer thread right regarding the vacuum lines and a tee or two?

Yea. I should be exactly the same as you.

 

[dannyvp]

Cut it off the pipe. Use two bolts to add it to the two threaded holes on the intake. The cable will need to be attached to that tiny threaded end. To wire it, you’ll need a piece of bicycle cable, choke cable (I replaced mine so used the junk one), or some sort of insulated cable. Regular wire will fry pretty quick after a few cycles.
If you want pixs lmk.

I’ll have to find some cable like that. I may temp wire it just to get it working though till I can find some.

 

[dannyvp]

Furthest screw out on the facing right of the carb. Pull the choke handle and get the RPMs to 1800. That’s it.

So once I do this and bring the engine to 1800, what do I adjust the screw to? Until I misadjusted the screw yesterday (with cars driving around me) I didn’t even have to touch my choke to start it. It didn’t even hesitate to start.

 

[g-man]

for the fast idle adjustment screw, you turn it til your engine is at 1800 but of course this is for a OEM carb...disclaimer i know nothing about a racer city /fuji carb!

 

[NeverGiveUpYota]

^^^ that procedure is what you would do.

 

[g-man]

actually you need to pull and plug your vacuum on your dizzy when you do this. (step B) disclaimer I am not a fuji carb mechanic!

 

[g-man]

I'm a bit worried that.....

At the next red light I was watching the RPM’s. It went from 1000 to 1500

is the main vacuum advance port on the dizzy hooked directly and only to the carb? If there is a VCV, VSV, VTV, BVSV in the line or "T"d into the vacuum advance, it could cause the vacuum advance to move and increase rpms. These valves open based on ...electrical signal, temp and other variables.

The new blue VCV that you installed ...it is only connected to the vent on top of the dizzy right? and not on either vacuum advance port?

 

[dannyvp]

My vac advance to the carb was unplugged somehow.
However that same line also connects to the vcv.