Technically speaking you should change the oil before you lay it up (a cheap one will do) as there will be corrosive acids contained in the existing oil from the combustion process. Then, when you re-commission the bike in the spring, change it again to your normal decent quality oil of choice as condensation will have collected in the oil used over the storage period.

There is no need to oil the top-end through the spark plug hole as used to be the case in the good old days.

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