- Joined
- Oct 28, 2014
- Messages
- 1,979
I have read many times that the weak point of the Mikuni single carb conversion is the manifold and that an improvement can be had by lengthening the manifold. However no one mentions the optimum length...perhaps this is still theoretical?
** How much distance is required? What is too long?
** Should the space be between the head and manifold or between the manifold and carb?
I realize there is a real lack of space so this is almost impossible to do but I'm curious. Has anyone experimented with this?
Last week I finally got out of Seattle and had long stretches of road where I could run the Atlas up around 6000+ briefly. I noticed the acceleration began to back off at the higher rpms. Could be any number of things. The jetting is typical Sudco...37.5 pilot #3 slide P-0 n-jet 6dh3 needle 240 main. The clip was in the # position - slightly richer. I put the clip in full rich position and felt a slight improvement. Yes, I read about the unreliable butt dyno. The Atlas is currently running the best it ever has so I am reluctant to increase the needle jet size. It is performing beautifully at low throttle.
** Also, the problem of testing the main jet. Is it possible to test the main jet by approaching a long hill approx 5000rpm in third gear, suddenly open the throttle all the way and hold it there for the duration of the hill...repeat with different main jets and compare?
I use the DENSO Iridium plugs IW22 5307...best bang for the buck. About $11apiece and worth every penny.
** How much distance is required? What is too long?
** Should the space be between the head and manifold or between the manifold and carb?
I realize there is a real lack of space so this is almost impossible to do but I'm curious. Has anyone experimented with this?
Last week I finally got out of Seattle and had long stretches of road where I could run the Atlas up around 6000+ briefly. I noticed the acceleration began to back off at the higher rpms. Could be any number of things. The jetting is typical Sudco...37.5 pilot #3 slide P-0 n-jet 6dh3 needle 240 main. The clip was in the # position - slightly richer. I put the clip in full rich position and felt a slight improvement. Yes, I read about the unreliable butt dyno. The Atlas is currently running the best it ever has so I am reluctant to increase the needle jet size. It is performing beautifully at low throttle.
** Also, the problem of testing the main jet. Is it possible to test the main jet by approaching a long hill approx 5000rpm in third gear, suddenly open the throttle all the way and hold it there for the duration of the hill...repeat with different main jets and compare?
I use the DENSO Iridium plugs IW22 5307...best bang for the buck. About $11apiece and worth every penny.