The chinese must have a dry sense of humor and plant problems with the engines and carbs just to see if we can figure it out. One of the guys had a new engine kit with the version 3 CNS carb. He couldn't get it to run right from the beginning and as soon as he gave it any throttle, the engine would bog and die. He placed a post looking for an NT carb as he was reading posts that the NT is a no nonsense carb that works when others do not. I replied and sent him a Speed Carb in exhange for his CNS. We did the deal and when I got it and tore it apart, it was unreal what I found. First of all, the main jet had no number on it(as most of them do not from the factory) but the hole was so small, I couldn't even get my smallest microbit to go through. The jet was real long and didn't even seat correctly. I replaced it with a #70 jet.
The carb comes with a brass plug covering the air fuel mixture screw so you can not adjust it. This must be a mandate from the EPA to make the carb unadjustable. I drilled a small hole in the cap and took a pick and removed the cap only to find out that the air/fuel mixture screw was turned the whole way in tight against the seat. The literature on these carbs say they are adjusted 1 to 1 1/4 turns and sealed. So I adjusted the screw to 1 1/4 turns out from the seat.
The brass slide pin has only one slot on it and I was concerned that the lack of adjustment would be a problem for mid range so I took a pin out of one of my other CNS carbs but the size and taper was totally different. I put the original back in, mounted the carb and took the bike for a test run not knowing what to expect. The 66cc engine, to my surprise, ran great right off the bat with no bogging, four stroking and had super throttle response.
In case any of you had one of these CNS V-3 carbs and were having problems, I thought I would post my experience in hopes that this will help.
As I said earlier, I can just see this little chinese guy laughing when he put this carb together, thinking to himself, lets see if "American" can figure out. Hope this helps anyone out there with the V-3. The CNS has gotten a bad rap out there but as we start to understand them through others experiences, I think they will not be so hammered.
The carb comes with a brass plug covering the air fuel mixture screw so you can not adjust it. This must be a mandate from the EPA to make the carb unadjustable. I drilled a small hole in the cap and took a pick and removed the cap only to find out that the air/fuel mixture screw was turned the whole way in tight against the seat. The literature on these carbs say they are adjusted 1 to 1 1/4 turns and sealed. So I adjusted the screw to 1 1/4 turns out from the seat.
The brass slide pin has only one slot on it and I was concerned that the lack of adjustment would be a problem for mid range so I took a pin out of one of my other CNS carbs but the size and taper was totally different. I put the original back in, mounted the carb and took the bike for a test run not knowing what to expect. The 66cc engine, to my surprise, ran great right off the bat with no bogging, four stroking and had super throttle response.
In case any of you had one of these CNS V-3 carbs and were having problems, I thought I would post my experience in hopes that this will help.
As I said earlier, I can just see this little chinese guy laughing when he put this carb together, thinking to himself, lets see if "American" can figure out. Hope this helps anyone out there with the V-3. The CNS has gotten a bad rap out there but as we start to understand them through others experiences, I think they will not be so hammered.
