From what I read, this problem has nothing to do with the carb. I’m certain it’s electrical because if it was the carb, it would not just stall while you are riding. Less than likely, anyways. The symptoms described by the OP are that of a faulty ignition. My first guess is the ignition coil/lead. It’s probably corroded to hell where the lead attaches to the spark plug cap. An easy fix for this is to remove the cap from the lead, cut a couple inches off the lead and screw the cap back on the lead. Even better, you can buy a new ignition coil, lead and cap for under NT$500.
If that doesn’t solve the problem, then you can get a made in Taiwan CDI for about NT$500.
A dirty carb can make the bike difficult to start, it can affect performance, it can cause a rough idle and stalling when stopped at a red light, but it will not cause the bike to stall while riding. OTOH, no spark caused by a faulty coil/lead/cap or CDI can make the bike stall at any time. Rainy humid Taiwan is hard on electronic ignitions, and few scooters make it ten years without needing a new ignition coil. The carb can outlive the scooter, though, without ever being cleaned.
As for carb cleaning, it can be tricky with older carbs. Many of them have rubber membranes, and air pressure is often enough to perforate old dried up membranes. From there the carb is ruined and the bike will never idle properly again. I would stay far away from the carb until I was certain that the CDI and ignition coil were in good condition.
This is an informative thread.
I, being for the most part rather mechanically inept, would posit that finding a reliable mechanic in any other country is difficult enough, much like finding a good dentist. I’m quite relieved to hear that I’m not the only one that has problem with local mechanics.
My usual chap tolerates, with something resssembling a grimace, my persistent approach to any recurring problem. His whole staff seem perplexed that I want my aging scooter to ride at least fairly well, as opposed to to some vacuous, “hey, it still runs…?!” approach.
By the way, how does one say ‘plug lead’ in Chinese? And what exactly is it, in English?
[quote=“sulavaca”]Threebond I recommend because it has certain advantages over other brands that I have used. Some sealants don’t dry efficiently and can leak immediately, especially when they come in contact with oil. Threebond mates surfaces together well as the consistency is more like silicon and less like glue, so it offers a slightly more elasticity which is great if the two faces move around a little during installation as the bonding tends to retain most of its alignment. Threebond is also not that difficult to separate once it needs to be dismantled again. Granted for some smaller mating surfaces that are more easily damaged it is best done with a razor blade and a small thin screwdriver, but I have never damaged any surface because Threebond was too strong, as it separates quite nicely. It really is a must, especially when sometimes you pop something open to realize you have just destroyed the original special gasket only to find you can’t readily get a replacement.
The next question I’ll be trying to find an answer to is where the hell can I get Threebond if not online?[/quote]
The stuff I used was called “Permatex B” and, although it works and is sold for engine assembly, and I can buy it in a local builders merchant/tool store, maybe I can’t recommend it.
I opened up the carb again because of an idling problem (I hadn’t cleaned out the idle circuit properly) and, where the stuff had been in contact with petrol, it had gone green and looked powdery. Didn’t inspire confidence.
I wonder how one of those “neutral cure” general purpose silicone sealants would work in this application.