Inition Timing

[AzWing]

Let's talk timing on our Beasts.

Initial timing on my '78 is 10º btc, the ''76 JunkYardWing is 5º btc.
What would happen if you advanced the timing on either of these bikes in stock configuration with stock carbs?

Advance another 5º or 10º and see if they run better? :YMCOWBOY: %%-

[Ed Z]

Damage will likely result... Most likely the fuel will preignite and cause both ring and bearing damage...

[admin]

If you can find some high octane fuel you might pick up a bit of power and fuel economy but it would all depend on the built in timing curve otherwise detonation might cause some problems. Timing needs to be correct, not just advanced.

[Badorderbob]

AZ is running a carb conversion,... like the old CI setups on the 1000's where they needed to advance timing to run :-\ :d Bob

[admin]

The reason they could run with the timing so advanced is that so much fuel is un-vaporized in the single carb setups that it actually cooled the incoming charge sufficiently to allow extra initial timing but it certainly is not efficient, horsepower or fuel consumption wise. This is also why single carb setups typically deliver poor fuel economy. Heating the plenum helps but it does not cure it completely due the fact that the fuel and air must make 90 degree turns causing the fuel to separate from the air causing puddling in the plenum.

[AzWing]

I don't know from efficiency.
The single progressive Weber 28/30 gives me 39.23 mpg.
The stock carbs never gave me better than 33. And the last two runs with them was down around 24 mpg.

I was really curious to know if it would effect the stock carbs and how.
I know how it effected my 1966 Olds Dynamic 88 with the 425 big block. Advancing the timing using a vacuum gauge increased the gas mileage on that 5300 lb beast from 9 to 13 over the stock timing. Plus the power went up also. I put over 360 thousand miles on that one, with a third of the mileage pulling a heavy trailer.

I would like to know if anyone has done it with the stock configuration carbs or not, and what their results were.

[AzWing]

Mine came with a 2GC 2bbl on it. That got switched for a Holley two barrel with the same bolt pattern when it decided to go south for the winter. Didn't even invite me along, turkey!