Also, I had the local kymco mech adjust my carb, I don't think it's lean (plug looks tan, not white, this is a good sign, right?)
I pulled and tested the by- starter, ohm meter read checks out. Put 12 v across it, and it seems to retract fully. If I understand this thing right, it functions some what a choke, only it allows more fuel in through a secondary, smaller jet, rather than restricting air flow. I searched the net, but could not seem to find out much on this thing.
Hi Tom
Its not very accurate in reading plugs on a scoot to tune. I will explain.
Yes, reading a plug is one way to see if your AF (air fuel ratio) is correct.
This way of tuning came from racers with manual transmissions. This how you can do it on vehichles with MANUAL transmission.
Install new spark plugs. Start the engine, run the engine up to max RPM.
Pull the clutch in at max RPM and kill the engine.
Coast to a stop.
Remove the spark plug and read it.
The problem with trying this tuning method with a scooter is you arent able to shut the engine down at MAX RPM.
I use a dual band AF meter and an O2 sensor on my scoot due to many different carb configurations and Nitrous Jetting with Fuel.
Before I had the AF meter I would just start by finding a long stretch of road and using a road sign, land mark etc as a point and clocking the top speed with a GPS unit.
I would start lean and increase the jet size until the MPH would drop. Then set the main jet that had the best top speed. After I had my main fuel jet dialed in I could set my needle height and spring pressure to my likings and this would usually be a short burst from take off such as 0-35mph or mark out 125 feet and and use a GPS to see what the max speed is within the 125ft from 0.
Reading a plug isnt accurate in jetting on a CVT transmission even more so if its not a brand new spark plug.
