Here is a post about fitting the oil filter:
I bought a Norton 850 oil filter head and filter from Ebay intending to fit it in the toolbox of my plunger frame GF as others have done. However, the assembly was too wide to fit in the toolbox so I have mounted the filter on the rear mudguard behind the gearbox using nylock nuts.
Both parts are dull black so fairly inconspicuous.
When mounted the filter head union stubs point towards the chain.
I've used Goodyear 8mm/5/16" ID reinforced rubber pipe to do the plumbing.
The oil feed pipe from the oil tank to pump union pipes is as the original.
The return from the pump is carried over the top of the gearbox, down between the vertical frame tube and the gearbox then gently curves around to meet the filter inlet stub.
The filter outlet pipe is routed tightly underneath the gearbox and then up behind the pump union assembly so it appears adjacent to the original metal pipes. It lines up nicely with the rocker feed banjo and oil tank connector.
Finished off with proper hose clamps it looks neat and not too obtrusive.
Here is a link to some photos of the setup.
http://tinyurl.com/cqbbnj7PS. This will not work for a Swing-Arm frame, as there is not enough room behind the Gearbox
PPS. Because the canister is mounted vertically virtually no oil gets spilt during changes. Any spillage gets caught in a drip tray.
PPPS. It's a cheap solution
PPPPS. No loss of tool carrying capacity