- Joined
- Nov 26, 2009
- Messages
- 3,152
Mick Ofield, who I raced with back in the day and who worked in the Norton factory racing dept, said I could quote him “no problem”:
"Jim, ... I vaguely remember your reed valve breather on the Norton. While at Norton, experiments were done running an engine at 7000rpm with the breather mounted at the lower rear of the crankcase. At this rpm, more oil was "pumped" up the breather hose to the oil tank than was coming up the oil pump return hose! ... Cheers Mick"
One time product announcement:
The Norton reed valve sump breather that I developed over 30+ years ago has been perfected. Long ago I worked at Sumner's Motorcycles in Fresno where they sold BMWs. So I chose the BMW boxer reed valve as shown below.
The new JSM reed valve sump breather
Features are:
Small size and low profile to reduce damage vulnerability (especially important on Vertical Norton twins such as the Featherbeds).
Clean and simple with only two external screws that can be tie wired for racing (keeping it simple was difficult).
Stainless steel main body.
Details like getting the hose barb oriented to the back caused delays. I finally went to various thickness nylon washers (3) – each subsequent thinner washer allowing the assembly to rotate a few more degrees. Plus the two screws allow the cap to be rotated 180 deg so it all works out. Note that Norton used a nylon sump washer around 73 and it has been reintroduced by RGM.
COMING UP:
When Mick Ofield worked at the Norton factory he recorded 45 pages of hand written race tuning notes complete with excellent hand drawings. He has agreed to publish these notes and make them available to everyone in a few months. Below is an example of one of his drawings.
I'll let you know when Mick Ofield's "Norton race preparation" manual is available.
"Jim, ... I vaguely remember your reed valve breather on the Norton. While at Norton, experiments were done running an engine at 7000rpm with the breather mounted at the lower rear of the crankcase. At this rpm, more oil was "pumped" up the breather hose to the oil tank than was coming up the oil pump return hose! ... Cheers Mick"
One time product announcement:
The Norton reed valve sump breather that I developed over 30+ years ago has been perfected. Long ago I worked at Sumner's Motorcycles in Fresno where they sold BMWs. So I chose the BMW boxer reed valve as shown below.
The new JSM reed valve sump breather
Features are:
Small size and low profile to reduce damage vulnerability (especially important on Vertical Norton twins such as the Featherbeds).
Clean and simple with only two external screws that can be tie wired for racing (keeping it simple was difficult).
Stainless steel main body.
Details like getting the hose barb oriented to the back caused delays. I finally went to various thickness nylon washers (3) – each subsequent thinner washer allowing the assembly to rotate a few more degrees. Plus the two screws allow the cap to be rotated 180 deg so it all works out. Note that Norton used a nylon sump washer around 73 and it has been reintroduced by RGM.
COMING UP:
When Mick Ofield worked at the Norton factory he recorded 45 pages of hand written race tuning notes complete with excellent hand drawings. He has agreed to publish these notes and make them available to everyone in a few months. Below is an example of one of his drawings.
I'll let you know when Mick Ofield's "Norton race preparation" manual is available.
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