Carb jetting


I'm,looking For a good starting,point for h,and l jet for 425 and 550 restrictor carbs akra big pipe motors


We ran 42/30 with cl-3 cam, green plate, and big pipe on 1/6 banked dirt oval. Throttle was wide open all the way around. Under cautions I told my son to hit the throttle and brake at the same time or under red not to let the engine idle. Got to keep the spark plug clean. We ran a 14-66 and came in at 5700rpm with 4-500 drops. This was winning ticket for us. Top two every race for the whole summer.

When we went to small track I went 10-60 if dry and dusty or 11-65/66 if track was tacky fast. That would come in at 6100 with 1000 drops.

When we went to blue plate on small track only I re-jetted to 39/28. I stayed with the same gear and came in at 6700 with 1000 drops. This worked well. Our kart setup was more important than ever. Once we got our tires and setup better we won some races.

We are now first year unrestricted. 38/28 jetting. Tires and setup is so important. It took us about 15 races then we found the winners circle. It was a variety of small adjustments and air pressure adjustments that we found worked. Can't wait for the new year to start. Hope this helps