O2 Weld On Bungs - (18mm + Radiused)

Sold as singles or choose quantity 2 for twin cylinders.

Use these beautifully machined 304 stainless radiused O2 bungs when wide band 18mm x 1.5mm O2 sensors are being added such as an Auto tune from Dynojet. New model KTMs use 12mm ports that will not work with wide band O2s and necessitate the addition of these 18mm O2 bungs. (Note: the Auto Tune kit comes with 18mm bungs but they are mild steel and will rust. These are for someone who want's the best on their stainless headers)

Notes, suggestions and precautions: Newer model 1190 and 1290 engines come with 12mm narrow band O2s. If Dyno Jet's Auto Tune is also being purchased, it comes with 18mm weld on bungs but are of low quality and will rust after welded. Use a 3/4 (20mm) hole saw or good quality step drill to make the hole before welding. Once these stainless bungs or Auto Tune's 18mm wide band O2 bungs have been installed, the user has two options:

1. Grind off the old 12mm ports in the exhaust and then add these or Auto Tune's mild steel 18mm bungs. You can then use our 12mm to 18mm O2 adaptors if for some reason you need to return to the stock narrow band O2s.
2. Weld these 18mm bungs just after the stock 12mm narrow band O2s and use these 12mm plugs to plug the stock O2 ports if removing the now not enabled stock O2s is desired.

OEM O2 Size By Model:

18MM

• ALL 790-901
• ALL 990
• ALL RC8

12MM

• ALL 125-501
• ALL 390
• ALL 690-701
• ALL 1050-1290