A/F Rich when cruising

käfertom · Posted: Sun Sep 27, 2015 11:37 am Post subject: It helped!!!

Yes, The CB-update-kit helped perfect. To double check these I built it back to 36mm vent with Weber aux. Bad, very bad. Thus, the kit (38mm vent with spray bar) in again.

udidwht · Posted: Mon Aug 31, 2015 11:05 am Post subject:

käfertom · Posted: Thu Aug 27, 2015 1:14 pm Post subject:

käfertom · Posted: Thu Aug 27, 2015 12:37 pm Post subject:

Baja_Tommy · Posted: Wed Aug 19, 2015 9:41 am Post subject:

I finally got around to making my progression holes accessible from the outside. I went as far as blocking the top 2 progression holes on each side. This had little to no effect on the rich spot. It did counteract the accel pump. Whenever I mashed the throttle it went really lean and richened back up. Why is that happening when I block progression holes and do nothing else?

Also with the throttle plate holes, the idle position just barely has the bottom progression hole covered.
_________________
A Baja Bug with some power is like a dirt bike. Quick not fast. Fun at low speed but scary at high speed.

If you're too old for dirt bikes, get a Baja Bug!

modok · Posted: Sat Aug 15, 2015 2:01 pm Post subject:

You have a lot to learn!
Your ideas make me angry.
I like that you have desire to learn! but I do not know why you dislike the weber carburetor and think it needs so many changes.

Do not bother with the CB update kit, just forget it exists.
Weber did a very good job designing the boosters FOR the application of a sportscar. The boosters and emulsion tubes may be the best ever, and this is because they were designed by experiment, many hours on the dyno and track.
You can make boosters that are better at WOT or boosters that are better at part throttle but I do not think both at the same time.

3.5=3.5mm hole. 4.5=4.5mm hole. It is the size of the passage the fuel comes out inside the booster. The hole is not round, it is rectangle, but the size refers to equivalent diameter if it was round.

Most systems of the carburetor are made to prevent the natural problem of being lean at low flows and rich at high flows, so this problem is a silly problem. I think if you are complaining about CRUISE speed you should use a model of carburetor that is made for cruising instead of a 44idf that has divorced idle system. The divorced idle system allows the use of larger venturies at the expense of less control at cruise speeds and transition. f-7 emulsion tubes......... and says it's having problems at cruise speeds well.....yeah. Of course! Divorced idle systems and f-7 emulsion tubes are made to make highly tuned racing engines that are using too big venturies to make big WOT power and not bog out of a corner and they didn't care one bit about fuel economy, AT ALL!

If you have lots of time learn to use a drill bit and solder to change holes in the emulsion tube. Try different vent sizes and jet sizes. Learn how the weber carburetors work before changing it.

käfertom · Posted: Sat Aug 15, 2015 10:23 am Post subject:

modok · Posted: Fri Aug 14, 2015 4:24 pm Post subject:

i don't think 5 exist.
3.5 do exist, I have some.

that is a silly way to delay the mains. it is much easier to lower the float level, use a larger venturi, or put additional holes at the top of the emulsion tube.
That is what a carbuiretor company would do, try it!

käfertom · Posted: Fri Aug 14, 2015 4:52 am Post subject:

käfertom · Posted: Wed Aug 12, 2015 12:26 pm Post subject:

Hi. The last test shows that the acceleration/half throttle situation is a little lean with the E/T F2. But the other readings are really well. And after changing to F7 the readings are extremely well. The car runs always between 12 and 13:1. It is only dependant on road nature. The only negative thing I noticed is a short lean spot at opening the throttles a little more after start up.
This is the result from a short test drive and I will test'n tune a little more.

These are the recent specs:
2007cc CR 9.8 Scat C25 D/P Head 32x35.5
Single Weber 44 IDF 61
Venturi 36
Idle 45
Main 165
Air 160
E/T F7
closed fourth progression hole

Image may have been reduced in size. Click image to view fullscreen.

käfertom · Posted: Tue Aug 11, 2015 6:24 am Post subject: closed fourth transition hole

I made a first test with closed fourth hole. This must be right way. After the 55s were crazy rich I changed the idles to 50s. Still rich (11:1) but at every speed below 65 miles with no rich spot. Then Car went to 13.5:1 on emulsion tubes and 12.5:1 on main jets. Now I change to 45 idles and F2 (from F11) emulsions. But testing that has to wait. I have to finish changing wheel bearings, brakes and axle boots.

But I am very confident with the carb mods.

Baja_Tommy · Posted: Sun Aug 09, 2015 2:28 pm Post subject:

I drilled a 1.6mm(1/16") hole in both of the throttle plates. Once I richened up the Idle adjustment, the idle speed was higher(1200 rpm). With the idle speed then adjusted back down, other than this change to the idle, there were no other noticeable changes with the holes and the air bypass screws open. No noticeable change to the rich spot.

I just remembered that I forgot to check the positioning of the throttle plate relative to the progression holes. That would have been helpful.
_________________
A Baja Bug with some power is like a dirt bike. Quick not fast. Fun at low speed but scary at high speed.

If you're too old for dirt bikes, get a Baja Bug!

modok · Posted: Wed Jul 29, 2015 7:00 pm Post subject:

lead/tin/silver
62/36/2

You could use any kind of solder, but life is short, use the expensive kind! It flows nice

Oh, and rosin flux and a tip cleaning set for acetylene/oxy torches.
Coat a tip cleaner in flux and just clean/flux the hole. that way the solder goes in the hole instead of everywhere except in the hole.

j-dub · Posted: Wed Jul 29, 2015 6:37 pm Post subject:

modok · Posted: Wed Jul 29, 2015 4:52 pm Post subject:

nope sorry. I use solder.

j-dub · Posted: Tue Jul 28, 2015 6:41 pm Post subject:

käfertom · Posted: Tue Jul 28, 2015 3:14 am Post subject:

rs58rag · Posted: Mon Jul 27, 2015 6:37 pm Post subject:

kafertom......difficult to see top drilled holes in progression circuilt, but they look like someone opened them up. Measure them, could be the culprit.

käfertom · Posted: Mon Jul 27, 2015 9:07 am Post subject:

käfertom · Posted: Mon Jul 27, 2015 8:45 am Post subject:

Hi.
I don't know the exact english term. But this is from product url:
"liquidmetal epoxy resin adhesive"
Hope that helps.

It was exposed to gasoline more than a year without any affect.


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