bakaracer wrote:keep in mind that on these bikes , its hard to get a really accurate plug chop since there is no clutch lever to pull in so when you kill the engine it stops right away.so the more the engine is turning the more the plug chop for wot will be not accurate.so the faster you can come to a stop safe the better the more accurate the plug read will be. plus you can tell also by feel and sound if the carb is to rich too so adjust jetting before doing a plug chop. again the jetting can be check with just a short ride down the street and back. no need for a 1 mile ride. if the bike is running crappy, dont waste a new plug on a plug chop. keep adjusting till it feels better then do a plug chop. if not your going to need a whole box of plugs.
I read on the wiki "From "Fred's Guide on How to Fix Your Moped,"
READING SPARK PLUGS and JETTING and PLUG CHOPS
Two stroke engines are sensitive to the level of heat inside the engine. The main jet size in the carb is the main determiner of how hot the engine runs at wide open throttle.
Too hot and they will seize the piston. Too cool means they are not making full power.
Engines get the hottest when they are running at wide open throttle making maximum HP.
"Reading" a spark plug is the best way to see how hot your engine is running. Reading the plug means looking at the ceramic insulator inside the plug and checking its color. The color will indicate the overall level of heat in the engine.
Reading the plug requires fully warming up the engine by running it for about 10 minutes... Then making a top speed full throttle run for a half mile or more, then killing the motor and stopping and pulling the spark plug on the spot. That is called.."Doing a plug chop".
When doing the "plug chop"... It is important to chop the throttle and turn the engine off with the switch or key and then pull over to stop... You don't want the engine to idle... that will change the plug color."
When it says chop the throttle, you mean you have it at WOT then let the throttle close all the way quickly, hit the kill switch and stop the scooter right?
Next question BAKA, you said if its running crappy, don't waste a new plug on a plug chop. Instead rejet and then do the plug chop. Are you implying you can only do 1 plug chop on a spark plug? As in, if you put it back in the motor and rejet, and you do a plug chop, you won't get an accurate color?
if you have a bench grinder it will be really easy. put one of those wire brushes on it and brush the piston skirts where it seized, not up and down but side to side then a light hone on the cylinder to get rid of any aluminum that stuck to it. also it wouldnt hurt to make sure that any edges are chamfered on the piston and the ports with a small file. The worst that can happen is you sieze the bore again. I have done this before so i know it will work. Just for giggles I took the stock bore and piston that came with my af16 when i got it that only had like 60 compression and would not start at all. Did what I described and replaced one of the broken rings and it cranked right up
