Nickodell - I'm interested in your jetting recomendations. Can you post either here or in a new topic? I think a lot of us would be interested!
Hi, Andy. I posted my own method last month but that was in the old forum. Basically, the so-called "idle" jet as fitted, which also controls the mixture in progression when starting from idle, in many of the Webers as delivered does not suit the Alpine engine. So you get a momentary leaning-out of the mixture until the engine speeds up, resulting in a stumble, or bogging down. In extreme cases the engine will stall on you, which can be a killer. You often won't notice this by blipping the throttle in neutral, it only happens when the engine is under load, i.e. when starting from rest.
Now you can play around by buying a series of increasingly larger jets, but being a skinflint I "did it my waaaaay." I happened to have a set of
very small drills which I use in my model railroading hobby. By very small, I mean the smallest are hard to see. For example, the largest one you can see here is 0.036" (36 thou, or 0.91mm), the smallest (which you can't) is 0.013" (0.33mm). You need this kind of set, as each drill increases by no more than 0.003"," or three thou. You won't find them at Pep Boys or Sears Hardware; you need a hobby shop, especially one that deals with micro-modelers like railroaders who scratch-build locos, or maybe a specialty tool supplier.
(Sorry about the poor image. Cheap digital camera that I keep meaning to replace).
You also need a micro-chuck drill. Power is neither necessary or possible, so the drill you use is a one-hand little device with a spiral body (looks like a Lilliputian Bendix drive) and finger pad. You also need patience, as you will need to bore several times in 3 thou increments to get the right result.
Anyhow, I kept boring the jet out and noting that the stumble got progressively less until, at 0.031" (31 thou, or 0.79mm) it disappeared altogether. I went to the next drill, 0.034 (0.86mm) just to err on the safe (richer) side as I reckoned it might need it on a cold start in winter (not that we've had a winter here yet: 60 deg. F again today).
If you go this way, be sure you blow out the jet to remove any drillings before reinstalling, natch.
