Scooterotica

Ok my scoot is a std Gp 150 with an AF Clubman small bore, jet ex carb with (if memory servers me right) +2 above std on the main jet

Its done about 8k miles since I built it without an issue but when I went to Cleethorpes this year After I got there I decided to check it over and noticed the plug was looking decidedly white. Can't say how long it's been running lean for as I've probably not checked the plug for a year or two (1or 2k miles). Shocking and lazy I know. Anyway I checked the air hose and filter and could not find any faults and as the scoot had got me to Cleethorpes from Manchester, drove it home as normal apart from adjusting the air mix as much as I could on the carb. Still ran it flat out but tried to make sure I was not sitting at a constant throttle position for long periods, which I probably was on the journey out.

When I originally built it I did proper plug chops and everything so it was definitely ok once and nothing much has changed since. Where should I look next for possible causes?

Air leak?

^ +1 or Fuel Flow ?

What grade plug?

"drove it home as normal apart from adjusting the air mix as much as I could on the carb." ?

If your plug is running too hot but not quite into the pre ignition temperature range it could be fairly white as it will burn off all the deposits, maybe try a colder plug

Rider error ....... White plug mixed with ...

Still ran it flat out

I'd have been flicking the choke on and off particularly any sections where engine under more stress, ie up inclines.

corrado wrote:Rider error ....... White plug mixed with ...

Still ran it flat out

I'd have been flicking the choke on and off particularly any sections where engine under more stress, ie up inclines.

You'd need long arms to do that with a flip choke.

wack 63 wrote:What grade plug?

It's a champion n4c

Not changed it since rebuilt it. Could it be the plug itself. I understand the idea it may be running hot because of the plug type but that has not changed since I last checked it when it was choccy brown

champion N4c is equivalent to NGK B6/7, try an NGK B7 for running around town and an NGK B8ES for fast running with that set up