Weber 48 ida synchrometer adjustment

[coinop101]

just sync my 48's at 6 kg/h . what is the correct kg/h ?? 427 fe

[lemans24]

there is no specific number, they all (4 in the center) just have to be pulling the same.

[dlampe]

That's an interesting question and the answer is going to be different for all of us but....

At 1000 rpm idle, I am set to 10.5 on all four. It would be interesting to know what the others are seeing.

[carmine]

Is that with the synchrometers rubber cork bypass holes turned to fully open position
or fully closed position?
I believe fully open is the norm for our application.

[coinop101]

Thanks for all your reply's .
Bypass holes were closed when I did mine .
Now my idle is smoother . I also don't smell the rich gas odor .
Still working on my timing . At 18 degree it tuff to start . So I am at 12 now .Need to test drive to work and see how she is on the highway

[Eljaro]

there is no specific setting. The vacuum generated depends on the engine size, camshaft profile, valve size and choke size. The important thing is to have all 8 throats tha same. Sometimes you may find that one carb gives different vacuum reading on the two throats. I have had to do some throttle shaft twisting to correct that.

[hendrix427]

Originally Posted by Eljaro

there is no specific setting. The vacuum generated depends on the engine size, camshaft profile, valve size and choke size. The important thing is to have all 8 throats tha same. Sometimes you may find that one carb gives different vacuum reading on the two throats. I have had to do some throttle shaft twisting to correct that.

I agree, that has always been my experience. I used to tune many cars with webers and when someone brought a car into my shop with tuning problems, I would always start at ground zero. Plugs, wires, points, coil, timing, etc. But even before those, I would start with compression and even better, a leak down test. When you have a engine with each cylinder having their own carb, any cylinder that has different compression characteristics can effect the performance. A leak down test combined with the compression test will prove to be informative. The leak down test can pin point problems with rings and even specific valves. As any weber specialist can attest, they are (especially IDA's) are very sensitive to tune. I would then pull them off the engine and very carefully inspect the throttle plates, bores, and shafts. Leaks around the throttle shaft bushings can be very difficult to fine tune and sync the carbs. When they are off the engine is also the best time to align and equalize all the throttle plates. Large bore engines are more forgiving than the smaller bores as far as tuning, at least that has been my experience.