Does your motorcycle clutch slip when it is under load or at high speed? If you have a wet clutch, the reason can be because fully synthetic oil or an oil with significant additives has been put in the engine. The additives in some oils are so efficient that once the plates have become ‘contaminated’, they loose their ability to grip. But if you are lucky you may be able to reclaim them by cleaning. In addition to this, oil that has sat in the primary case can cause lacquer build up on the plates.

Dismantle the clutch. If the plates with the bonded material look good (ie deep groves in the material),then wash the all the plates thoroughly in petrol (gas for us Americans!) While they are drying, drain the engine of the synthetic or oil with additives and replace it with a clutch friendly oil.

Replace the cleaned plates and fill the engine primary chain case with an oil that is wet clutch friendly. Read the labels of the oil you wish to use. If necessary go to a bike shop and read the labels. Hopefully this will do the trick! If the clutch still slips, this indicates that the additives from the oil have impregnated the plates, so you will have no other alternative but to replace them. I have limited success with cleaning the plates. In most cases both the Driven and Drive plates replacement are necessary to correct the failure.