A Kawasaki ZRX1200 we purchased for spares had a major issue with the engine (specifically the clutch). This problem seems to be a weak point in the ZRX1200 and ZRX1100 engines.
The pictures below show what can happen if the problem isn’t corrected in time. It’s worth noting these pictures came from a regularly serviced bike with 30k miles on the clock (so not high mileage).
Although we always recommend using a good quality motorcycle oil, it probably wouldn’t have helped in this case.
Damaged ZRX1200 clutch basket after the chain tensioner failed.
The issue with the Kawasaki ZRX1200 alternator and starter chain tensioner is that the standard, spring-loaded tensioner can become weak or fail completely over time.
When this happens, the tensioner arm can over-extend and come into contact with the clutch basket causing damage.
In a worst case scenario (like the clutch basket pictured here) the tensioner arm can come completely out of it’s socket and cause major damage to the clutch basket
Damage to this clutch basket has been caused by the chain tensioner are (top of the pic) jumping loose and striking the clutch basket.
How the problem occurs:
- Tensioner Design: The ZRX1200’s alternator and starter are driven by a single chain. A spring-loaded tensioner located near the clutch basket keeps the chain tight.
- How it fails: The stock tensioner spring can weaken over time ot the tensioner mechanism or chain can fail.
- The Result: When the engine is turning over (especially at startup) or while running, the tensioner arm can swing out of position too far and physically hit the clutch cover or the clutch basket causing damage.
- The Damage: This repeated impact can chip away at the clutch cover and clutch basket. Small metal chips from the clutch basket can then circulate in the engine’s oil, potentially causing damage to other components such as the oil pump or bearings. In more severe cases, a complete tensioner failure (e.g. a broken spring) can lead to catastrophic damage to the clutch and engine failure.
Metal debris and broken clutch parts from the damaged clutch basket in the oil sump.
There are a few ways that may help prevent this issue:
- Sound: A tell-tale sign is a clank or thunk sound from the right side of the engine (where the clutch is located) when you first hit the starter button.
- Visual Inspection: You can remove the oil filler cap and look for dings or marks on the perimeter of the clutch cover. This is a common indicator of the problem.
A cheap (plug into your phone type) endoscopy camera is a great tool for checking things like clutches. - Oil Flakes: Finding metal chips in your oil filter or on a magnetic drain plug usually indicates an issue which could be the tensioner failing.
The above parts were found lose behind the engine casing.
Fixing the problem…
Many ZRX1200 owners have replaced the stock tensioner with an aftermarket tensioner. These are typically made from billet aluminum and have a fixed, adjustable stop that prevents the tensioner arm from swinging out and contacting the clutch which eliminates the risk of damage.
Disclaimers:
The information provided on this page is ‘to the best of our knowledge’ and should not be taken as 100% accurate!!
To keep this page as a free resource for people to use, there are affiliate links (mainly Amazon) throughout the article. These affiliate links help maintain the cost of running this blog (basically, if you visit Amazon through one of the links and buy something, we make a few pence!).
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