The Kawasaki KDX 200 or 220 looks like a realy good fit for a Vespa topend conversion due to stroke and bore being almost the same. However, there is quite a bit of modification to do to the cases due to the height that the cylinder sits on the PX cases. The 220 is a lot harder to come by so we chose the 200. If we have to go bigger we may be able to get a 220 sleeve and do some porting. Another alternative is oversizing.
Scooterhelp talk about it for Lambretta's (Kawasaki KDX200 Cylinder)
The KDX also has a bigbore kit see: 240 Big-Bore Kit for the KDX200
JustKDX info
KDX dyno (note this may be an old KDX)
KDX forum
Wiseco Information
Wiseco Pistons etc
KDX 200
With the KDX crank the 200 is 198.51cc, with the Vespa 60mm long stroke we end up with 205.35cc.
KawasakiCycleDirt.pdf
| Model | Years | Bore
x
Stroke
(mm) | Bore
Size
(mm) | Forged
Wiseco
Piston | Repl.
Ring Set | Repl.
Pin
& Clips | Top End
Gasket Kit | Top End
Bearing
| Main
Seal Kit
| Main
Bearing
Kit | Forged
Wiseco
Connecting
Rod Kit | | KDX200
Pro-Lite
Electrofusion Bore - Cylinder
sleeving or replating required
for oversizes.
| 1986-06 | 66
x
58 | 66.00
66.50
67.00
67.50
68.00 | 711M06600
711M06650
711M06700
711M06750
711M06800 | 2598CD
2618CD
2638CD
2658CD
2677CD | S255
CW16 | W5456
1995-05
$38.91
(D4332) | B1008
$14.95
(D798) | 1992-06
$19.95
(D7911) | BK5006
$24.58
(D5741) | WPR131
1989-04
$97.25
(D1236) |
The biggest we can go in the 200 is 68mm bore = 217.99cc (with 60mm Vespa long stroke)
For the 220, bore 69-70mm = 224.45cc-231cc (with 60mm Vespa long stroke)
Top End Bearing
Comp-PinsClipsBearings.pdf
Part #
| Inside Diameter (mm)
| Outside Diameter (mm) | Length (mm)
| | B1008 | 16 | 21 | 19.5 |
Both the wrist pin of a Vespa PX and KDX are 16mm, so a KDX piston can be used on a Vespa conrod (with a Vespa topend bearing).
| 
