Thanks for your reply. The stock jetting on an airhead is set for sea level, so the stock jetting works well up to 5000 ft, if you are consistently over that then re-jet the main, to limit the amount of fuel available. Changing mains, clip positions or needle main jets are fairly major changes. I found through my experience that the engine was slightly deader with a 2.68 needle jet, but it ran better with the stock set up. I changed the pilot jet because it was a very cold blooded bike at startup. Once I changed the pilot jet to a # 50, cold start, idle when hot etc all got better. Bike pulled well throughout its rpm range and would still accelerate under load at road speeds. The main only comes into play at 3/4 and up throttle position, and basically only really matters for wide open throttle. If the bike keeps accelerating at say 60 mph + (with minimal wind conditions ) then you are good at the main jet.
The slightly larger pilot jet allows the entire fuel circuit to be slightly richer as it never shuts off and is always adding gas to the intake air stream. If you talk to somebody who has gone to the Mikuni carbs, you'd be surprised how lean they are set up to run on an airhead. You get maximum power, at around 13.8 A/F mixture and when you consider that the stock jetting is getting you in the range of 14.6 A/F ( going down the highway at highway speeds, it is richer in the lower throttle positions ) it doesn't take much more fuel to get the engine in a happier position.
If the setup I ran with a sidecar rig, engine has to work much harder, with no lean indications, it likely will work well on any airhead running below 5000 ft altitude. I got the tip of the # 50 idle jet off a sidecar site, from a response form a question asked to a bing specialist. It worked for me, so I pass it on for what it's worth. Sorry I tend to get too long winded.
The slightly larger pilot jet allows the entire fuel circuit to be slightly richer as it never shuts off and is always adding gas to the intake air stream. If you talk to somebody who has gone to the Mikuni carbs, you'd be surprised how lean they are set up to run on an airhead. You get maximum power, at around 13.8 A/F mixture and when you consider that the stock jetting is getting you in the range of 14.6 A/F ( going down the highway at highway speeds, it is richer in the lower throttle positions ) it doesn't take much more fuel to get the engine in a happier position.
If the setup I ran with a sidecar rig, engine has to work much harder, with no lean indications, it likely will work well on any airhead running below 5000 ft altitude. I got the tip of the # 50 idle jet off a sidecar site, from a response form a question asked to a bing specialist. It worked for me, so I pass it on for what it's worth. Sorry I tend to get too long winded.
