- Jul 23, 2014
I spoke with Mike Patrick a few times about some of the many modifications he made to keep 121013 out front. It was always a work in progress. There were many repairs made to the continually cracking frame because of the engine mass. He also said that the Teledraulics were inadequate for him and quickly changed over to the long Norton Roadholders as fitted to the early Atlas scrambler, N15's & G15's. He said that his P11 was his only racer that never threw him over the bars. I also asked him about the feeble way the front brake torque arm was attached to the left hand lower slider by the 1/4" fender mounting studs. The alloy was breaking away at the mounting holes. He said he stopped racing it before it was a problem and he didn't use much brake anyway with engine compression and light braking with the rear brake being sufficient. There were so many modifications made to that racer it would be a whole new thread to list them all. Maybe I'll start that thread one day? Right now I'm too busy getting ready to take a couple of 50 year old Norton's on a trailer pulled by a 25 year old mini RV on a 2 thousand mile round trip to the INOA rally and catching up with my wife's Seattle family. What could go wrong?
Teledraulic forks were used in heavy 500cc scrambles in the 50's and 60's including jumps and hard landings with no ill effect as far as I know. P11s were entered in scrambles events as well.
However, I just discovered that Mike Patrick's old race bike was retrofitted with Roadholder sliders, so maybe his forks did suffer from slider cracks. We will probably never know.
The alloy is now 50+ years old and it will be affected by fatigue.
Ideally, oil pressure on the compression stroke affects the bottom of the slider only, but with a worn slider and bottom bush 021495, compressed oil will leak by and excert radial pressure on the slider's upper part as well.
In addition, there is the mechanical load trying to bend the slider, but that load will not generate hoop stress cracking as seen in the picture above.
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