In order for the fan sensor to work there must be water flowing through the radiator. One of three things could be preventing this from happening: 1. a clogged radiator 2. a thermostat which is not opening to allow hot water from the engine into the radiator 3. too much air in the system which is restricting the water flow.
Check the inlet and outlet hoses on the radiator after the engine is warmed up to see if they feel hot.
Hi bobf. I also have a Jonway scoot with the 244cc Honda clone engine. Chinese clone engines do not usually have Keihin carbs. They usually have the zinc alloy Chinese clone carb. Here's a link to a Chinese clone which should fit your scoot. A big cost savings over the Japanese carb.
My Jonway YY250T came with 23 x 18 weights that measured at 24.5 grams. I installed 19 gram Dr. Pulley sliders. Low end acceleration was greatly improved and I can still pull 70 mph. I think this was the ideal weight for my scoot.
It sounds like you eliminated all possibilities down to the starter. I would try running an additional ground from the battery directly to the engine which would eliminate possible problems with the ground circuit between the engine and bike frame and also the battery and bike frame. BTW you sure seem to have fast shipping with your batteries. I have been curious how the lithium batteries will work in our scoots as far as longevity and reliability.
I have HID's on my YY250T. I run only one light for the low beam and two for the high beam a la Reflex. Running just one headlight helps save the battery on the YY250T which has a marginal charging system. These lights are quite bright even with only one on. I also run 7 watt LEDs for the running lights to improve my daytime presence for other drivers.
Any 12 volt horn would work. Car horns and air horns are popular replacements. Anything louder than the OEM horn should be installed with a 12 volt relay to handle the extra power requirement of the louder horn. I like the Wolo Bad Boy which I use in both of my scoots. The compressor and horn are one compact unit, but they can be split up for use in tight quarters like on my VIP50.
Check the vacuum lines for cracking and dry rot. They should be soft and hopefully a good quality American line. These lines are normally replaced as part of a PDI which is performed when you first get the scoot.
The main reason for the difference in oil change intervals is that the Honda has a Japanese engine and the Chinese clone has a.... Chinese engine. Chinese engines do not have the same quality parts and metal. The softer metals in the Chinese engines will wear faster and contaminate the oil faster. Since there is no true filter, the more frequent oil changes are suggested.
BTW- the Helix oil change interval is 1250 miles while the Reflex is 4000 miles. The Chinese clone is a copy of the Helix engine.