The 38mm is for the 39-40mm hole and is the closest size manufactured so will require a bit of glue/silicone for security.
Motorcycle Frame Plugs to fit Kawasaki 1400 GTR and ZZR Frame Plug holes
PANNIER LINER INNER BAGS FOR KAWASAKI 1400 GTR
Pannier Liner Inner Luggage bags for KAWASAKI 1400 GTR Pair Motorbike
Kawasaki 2006-2020 ZZR 1400 & GTR 1400 Racing Radiator Guard Zx14 ZX1400
Motorcycle Handlebar Risers For Kawasaki For GTR 1400 ZG1400 For Concours 1400 2008-2020 Motorcycle Handlebar Riser(Silver)
AGM Motorcycle Battery for Kawasaki ZX12 GTR 1400 VN Quad 360 Replaces YTX14-BS
