350X FCR Carb Jetting

[eric95]

I have a new 38mm FCR carb on the way to complete my 350X build. Anyone with experience with the FCR have some ballpark jetting sizes that would give me an idea where to start? Motor is very mildly built with a 10.5:1 piston and Empire full exhaust.

[shortline10]

I would think somewhere from 120-170 on the main
36-42 on the idle jet .
I would start small and work your way up .
If you get an off idle bog or stumble play with the needle clip .

[Dirtcrasher]

With an Empire and open air box lid (to get the best air flow) you are gonna end up in the 160 - 170 main range and you can play with your pilot. More importantly is the leak jet, the smaller the jet the bigger the squirt, I forget what leak jets I have bought I had to buy them from Suddco to get what worked on our engines versus modern engines with a hot start lever. I just hit the thumb throttle and that big squirt is my choke so to speak, while the motor is running that leak jet will add more fuel every time you stab it. You can change that leak jet and watch the difference in the squirt, there is also a duration (length of time) of that squirt. I have the 32mm FCR on my 86 200X (has lots of work) and a 39mm or 40mm FCR on my 350X, my 452CC motor uses a 41MM FCR I believe. They are a big carb physically but they definitely add performance... I have my exact specs written down in one of these notebooks if you get lost.