So today i thought id better take a look at our friend Marks moped. Its a Motobecane similar to the brown one Sinclairio has but this one has rear suspension.
Before i could work on the engine i had to remove the aweful leg shields which was easy enough and also the engine side covers. Now that i could get access to the engine it was time to check all the usual suspects. First off i checked the spark plug and found that the plug boot had melted so it wasnt clipping onto the top of the spark plug. I replaced the boot with one from and old lawn mower which i had lying about.
Here you can see the condition of the spark plug from the look of it its been running rich which isnt really a problem but the gap was massive and the arm over the electrode was bent to one side. I replaced the plug with a new one. I checked and it was getting a spark. Next i drained the remains of fuel from the tank and flushed it through with fresh fuel and left a bit in there. Stared the bike but it was still running rough.
The next thing i did was remove the carb which i noticed was mising its plastic cover and covered in crud. I broke it down and cleaned everything with carb cleaner and then reassembled.
Once i had done this the bike started straight up and with a slight adjustment to the idle screw it was idling perfectly.
Finally i took the bike for a little test ride and remembered how slow these bikes are without a variater. 25mph top speed with a bit of a bog at low end.
So the next thing to do is do some plug chops and establish whether its running rich or lean then i can figure out how to adjust it so it wont bog down at low end.