by RCWSO » Sat Jan 05, 2013 7:25 pm
I believe I have fixed my problem. Here is what I did and found.
I literally took the carb apart about 15-20 times. I changed the main jet, pilot jet, rebuilt the whole carb, changed needle positions and non of them in any combination helped my problem of 1/4-3/4 throttle with a loss of power. I emptied the fuel tank, cleaned it and the valve. Did the WD40 air leak test. Checked the grounding wires. Checked the float levels.
What I found after cleaning the carb one last time was a part that I did not clean very well the other times. I don't know what it is called but it is the threaded tube that the main jet screws into. that tube threads out of the carb housing where the needle comes in. That piece has many little holes in it which I did clean before. Although, this last time I noticed the threads on the piece were not very clean on the inside of the carb or the brass piece itself. There was corrosion on them. I cleaned them very well and screwed that piece back in. This time it went in about 1/8 of an inch further than previous times. I put the carb back together and the bike runs great now. No loss of power at 1/4 throttle. Full throttle response. I ran the bike for about 20 minutes today with no issues. I will take it out this week or next to give it a better run. I believe I found the problem. That piece not threading in all the way in the carb made the main jet stick further into the bowl causing a very rich condition. As if I had put a larger main jet in with the longer size and without the larger hole.
Anyway, long answer but I learned that when cleaning the carb out I should have been more diligent the first time. I didn't even notice the dirty threads the many other times.
I hate to suggest it, but maybe take it apart and scrub everything one more time. Let it soak, scrub, reset everything to stock settings and give a try. I was ready to purchase another carb and gave it one more chance. It was amazing how much more gunk I got off the carb the last time.
I hope that this was the final time for a while. As mentioned, I ran it for a while today with no problem. Idles great and starts on the first kick or two every time.
Wish I would have been more diligent the first time.
Good luck and let me know what you find.