Kawasaki has rolled out a recall for the 2020 W800 Café and the 2020-2021 W800. The exhaust nuts may not be tightened properly, causing them to vibrate loose.
In April 2020, Kawasaki Heavy Industries (KHI) received a notification from the Japanese importer (KMJ, Kawasaki Motors Japan) that on a W800, the exhaust outer shells were not screwed on tightly enough and the nuts and exhaust ring had come loose.
An investigation was immediately started at KHI, but no abnormalities were found in the production process. Inspection of the data showed that on all defective vehicles the nuts were tightened with the correct prescribed torque.
The reason why the nuts had vibrated loose remained a mystery. In a test where the nuts were tightened with a tightening torque less than the specified torque, the nuts did not vibrate loose. The dimensions of all offending parts were checked, but that too was within tolerances.
After that, several more tests were done that showed nothing, it was not until September 2021 that it was found that the value of the tightening torque decreased drastically when the exhaust nuts were tightened without the exhaust system being temporarily tightened first.
When the pipe mounting is first tightened and then the exhaust suspension brackets, the entire exhaust system comes under tension. The correct procedure is therefore first the exhaust suspension brackets (temporary or not) and only then the pipe attachment of the exhaust bends (to the block).
The exhaust rings and gaskets will be replaced at the Kawasaki dealer and the exhaust system will be tightened in accordance with the correct procedure. From August 2021, the correct assembly procedure has been adjusted in the assembly.
– Thanks for information from Motorfreaks.