Motorcycle Repair: Honda FT500 Carb Issues, honda ft500, microfiche services

Question
Hi Bill,
I have an FT500 Ascot and have been cleaning my carb. As I use the bike for a daily driver I sourced a spare from the wreckers. I cleaned and installed the spare carb which ran fine but was difficult to start. With the choke out I still had to give it throttle to run till warm. Once warm the idle was fine at 1200rpm. I cleaned and reinstalled the old carb which starts and runs fine. My question is what settings make the 2 carbs different. one needing throttle and choke to start and one choke only?

Answer
Gordon, for some reason your latest carb install has a bit of leaness in the bottom end. I haven't seen one of those carbs for years, but some Honda carbs had a fast idle adjustment that went hand in hand with the choke application. More choke, more fast idle. Yours may be out of adjustment if it has that feature. Perhaps your choke adjustment is different on that one than the other. Choke cables are adjustable to a certain degree.
Other issues are the possibility of a slightly lower float level, differences in the number of turns out on the idle mixture screw, possible air leaks in the manifold.
You said you cleaned this carb, but did you just squirt a little carb cleaner here and there or did you completely disassemble it and soak it in carb cleaner? There are tiny cross drilled passages in the emulsion tubes that are often overlooked.
I know some small changes were done to these bikes from 82 to 83 and perhaps there were some differences in the calibration of your two carbs. The online microfiche services show some different jet options for this model.

Bill Silver