Old Britts – Modified Commando Tach Drive Housing with Oil Seal
Download the complete PDF version using the green download button at the top right of this page for an Old Britts reference covering a modified Norton Commando tachometer drive housing fitted with an oil seal. This short technical sheet shows the machined housing arrangement developed to accept a Honda seal, intended to reduce oil leakage at the tach drive area. It also notes that Old Britts later stopped offering the modification after developing an electronic tachometer option.
The article identifies the seal as Honda part number 91207-222-000 and shows a side-by-side comparison of the modified tach drive housing before and after the seal is installed. The housing without the seal is shown on the left, while the finished housing with the black oil seal fitted is shown on the right.
A CAD drawing on the same page provides machining reference details for the seal bore and mounting-hole relationship, giving useful information for anyone wishing to perform the modification themselves or have a local machine shop carry it out.
Contents Include
- Modified Norton Commando tach drive housing reference
- Oil seal conversion for the tachometer drive area
- Honda seal part number 91207-222-000
- Comparison of housing with and without the seal installed
- CAD machining drawing for the housing modification
- Note that Old Britts no longer performed the modification
