My '04 KX250 /BB 300
Owned since new, raced for many a seasons in Enduro's then was parked for about 2 years in pieces. Decided to finally big-bore up to 300cc, welded-up & repainted the frame, swapped over my enduro goodies (200w E-line lighting coil, 18" rear wheel, '03 KX250 open-chamber forks, Flexx bars, 13/52 gearing, etc). Used thinner base gasket then stock to bump compression up & running on 110 leaded race juice with spot-on jetting. I now kick my self in the arse for not having done the big-bore sooner! 6 months in & it's still tight as ever!
Picture from the first full season on him when he was new:
In old race garb from around the 2nd season