Friday, November 26, 2010

Making Headway

The first order of business on the Norton Model 7 was to replace the rocker oil feed line. The original had a a kink where the banjo fitting meets the oil tank union. My concern was that the kink restricted oil flow to the top end impacting its lubrication.

Original line with kink

I purchased a new line from Norvil. Norvil offers two varieties of rocker oil feed lines. There is a one piece version and a two piece. I chose the one piece thinking that the clear plastic tubing wired to the original feed line was a bodge like many other fixes on the bike. The more I thought about it I came to realize that it was a smart modification that did two things. First, the plastic tubing serves as a sort of shock absorber dampening vibrations that could damage the soldered joints. Second, the clear tube serves as a sort of sight glass allowing me to visually ensure that oil is going up the line. It doesn't guarantee lubrication but I figure that between the visual confirmation and the pressure gauge measuring oil pressure off the scavenging side I'll be pretty safe.

First, the tear down started easily until the removal of the oil tank. Stripping off a Model 7 oiltank requires the removal of a screw buried behind the battery carrier. The only problem is that the bolts for the battery carrier are behind the oil tank. Needless to say, a few contortions later and I got the tank off without having to take off the battery carrier.

I did a test run with a length of wire coat hanger and cut the feed line at approximately the point I wanted the clear tubing to be situated. The hacksaw is a british item that stabilizes the blade via a springloaded guided that minimizes wobble providing a nice clean cut. Get it at Garrett-Wade.

Considering that the tunbing is zinc coated copper, bending requires the use of  a tubing bender to avoid putting a kink in the line. The bends were compound ones requiring bends in multiple axes. The tubing bender is available at Eastwood Company here in the USA

After some deburring and polishing I ended with this.

The final product fits very well although the picture above is one step shy of completion. Thinking I was done, I am now taking the opportunity of easy access to the gearbox adjuster now that the oil tank is removed to do a much needed clutch/primary drive overhaul. Stay tuned for that adventure. 

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