Well I finally got the KDX400A1/KX250A5 finished, now to test it out at The Farm this Friday. I have the '84 KX front end for the 'Pre 90' Thumpercross event in a couple of weeks, after that I'll put a sorted Evo front end in it for Open class Evo.
Mods ....
KDX400A1 '79 engine.
As new complete gearshafts replaced.
NOS shift drum.
NOS shift shaft.
NOS std bore KDX400 piston, rings, pin & small-end.
New main bearings and all crankcase seals.
Resleeve with sleeve thick enough to go to a 3mm bigger KX420 piston at a later date.
Ported barrel (opened tiny exhaust ports).
Increased reed-valve flow area 20% with full carbon reed petals.
New clutch plates.
Heavy duty EBC clutch springs.
New swingarm bearings & seals.
YSS rear shocks with adjustable compression & rebound damping.
New .46kg fork springs.
New headstem bearings.
KX250A6/420 triple-clamps have 10mm less offset, down from 35mm to 25mm, for more trail.
KX500 '84 lower chain guide.
New sealed chain rollers.
Std KDX400 pipe cut-up to fit.
Rear KDX400 engine hanger modified to fit 250A5 swingarm.
Hand-made front engine mounting plates.
Lower rear engine mounts cut-off and repositioned.
New folding gearlever.
Footpegs widened.
Still running KDX stator (external flywheel) with lighting coil.
New Nightmare plastics.
New Unifilter aircleaner.
KX250A5 38mm carb.
New clutch & throttle cables.
New kill-switch.
Ordered custom made KX400 decals (coming).
