Timing Advice

[alvin l nunley]

I was aware. I just wanted to post for amatures like me who check the historical data on the site to try to learn a little or looking for some advice.

I wasn't aware that a post could ever be "over with".

 

[alvin l nunley]

I am planning to go down to a .020 low speed idle jet and keep the .035 main with the 140 E-tube. I have also read that .018 low and .032 main with 140 E-tube will run but I have not tested how well this runs. I would imagine it would be a little more difficult to start and would have trouble idling down and backfiring through the exhaust. Bear in mind that this set up is for off track recreation use and not racing.

Did you see where I said that a .021" to a .020" is a -9.25% decrease in jet flow? I might have given you the 20 to 21 measurement. Going down is a smaller percentage than going up.

Every plug reading article I have ever read shows the plug with only a slight amount of color when the engine is tuned and running correctly.

Just for your information. .021" to a .018" is a change of -21.6%.
.035" to a .032" is a change of -16.4%

 

[W5R]

If your engine is jetted anywhere close to where it should be, the plug will almost akways be black on these engines.. Every good engine I have had was that way, you can't really read the plugs on these engines easily, dyno is the best way to tune the jetting

 

[sledge]

adult = 33 degrees BTDC / jetting = .038 hi - .021 lo
green = 37 " " .040 .022
blue = 35 " " .039 .021

these are good starting points, try to get the engines to run around 400 degrees F. by playing with jetting.