So my colortune doesn't respond...

[B4S]

I've been trying to set the idle mixture on my DHLA40Hs for the past two days now, and I'm at my wits end. The throttle plates are as closed as they can be, to minimize progression hole visibility, but because they are emissions models, the first hole is half uncovered anyway. The first time I balanced them I used the bypass screws, but at that point, the mixture screws couldn't get the colortune to show anything but white-blue. The idle circuit is clean and clear, I cleaned it out thoroughly before I installed the carbs. I've got a set of non-emissions Mikuni 40PHHs waiting in the wings, and am curious to see what everyone's thoughts are on the emissions Dells. I'm using them on a 1.8, 10:1, 8v VW motor and my Des Hammill book has said that the larger displacement motors work well enough with the emissions carbs.

I'm going to try not using the bypass screws tonight when I re-balance them, but I suspect I'll have the first progression hole wide open...which couldn't be good for the idle mixture I'm sure.

Swap to Mikunis...or stick with the DHLA40Hs? I'm after most flexibility, and tend to lean towards midrange. 32mm chokes .

[velocedoc]

Do you have the right set of idle jets for this engine? If the color is white blue, it is obviously to lean at no matter what you tune the idle screws. If the idles are two turns out, you should have a blue/orange color. One turn out should make it go orange and one turn in blue/white. This is only a starting point.

[B4S]

I re-did my balance tonight, turns out the issue is my attempt at using the bypass screws to keep the throttle plates as close to shut as possible in a vain attempt to get more progression 'sweep'. I closed them off completely and balanced them like a non-emissions carb. VOILA! The colortune reads properly, and I went from 5 turns out on the mixture screws to 3-3.5. There is no hesitation from idle, and the idle is a rock steady 1000 rpm (right where I want it). Before I turned the mixture down, the flame was definitely orange too. I love this thing .