plug is a ngk BR8ES
there wouldnt be a carbon build up coz its a fresh rebuild, hasnt even done 100m yet so all clean inside

just checked the spark to, its quite white/grey so looks like its running real lean

ill start the search of an air leak

thanks for advice !

ahh ok
but the thing is this is a re-occuring thing
any idea what could be causing it?
i was thinking maybe mixture is to lean and causing it to overheat ?
or maybe water isnt flowing through engine?

the thermostat has been removed so the engine should be cold
(temp sensor and all other gauges ...

its an mkI 250
recent rebuild
ok so i start it up and after it runs for a bit the rev's jump up and the bike idles on medium rev's

so i flick the kill switch and the bike still runs
so i kill the fuel and remove fuel lead all together from tap to carby
but still runs coz of fuel in bowl
so i ...

hey my mk1 was modified by previous owner and only electrics remaining are essentials to run the bike and work the power valve servo(all lights/indictaors have been removed).

when i bought the bike it sparked, but now ive put it back together it wont spark!
all loose ends in the loom are cut so ...