Unofficial Royal Enfield Community Forum
Royal Enfield Motorcycles => Vintage Royal Enfield => Topic started by: tamalecks on July 20, 2011, 04:22:57 pm
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Will these parts from a 90's 500 single fit a '67 Interceptor? The gear lever part# 143745 and the brake rod part# 144008? Will the original wing nut adjuster fit the threads on the new rod? I am planning a set of rear controls and need these parts to avoid ruining the originals. Thanks. Al.
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I would say the better place to ask that would be by calling the store. Hitchcocks' in England is also worth asking, and they del with lots of older part machines. Might be worth the call to them.
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Hitchcocks will know for sure. The Indian brake rod is the same diameter but is shorter. ERC
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All the old Redditch UK Royal Enfield twins used British Cycle thread for near all the threaded fasteners. I don't have any idea what the Madras/Chennai India manufactured bikes have for thread. It could be metric, unified, or British standard cycle.
Does anyone know off the top of your head?
The pre-1956 type frames that the Indian bikes are patterened after have different dimensions than the 1956 and later Redditch type frames had.
PS: I think I answered my own question, at least for the rear brake actuator rod. Hitchcocks list 5/16-26 tpi for mid 1994 and earlier but metric for mid 94 &later models.
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5/16-26 is not a standard UN (Unified National) thread as used in the United States.
The standard UN threads are 5/16-18 UNC and 5/16-24 UNF.
There is also a metric thread, size M8 x 1mm that is close. it has a major (largest) diameter of .315 (vs .3125 for a 5/16") and the 1mm lead equates to 25.4 threads per inch. This is very close to what would be a 5/16-26 (assuming the "26" was not a typing error).
While it is "close" I wouldn't recommend using the Metric fastener in place of a "5/16-26" thread unless the length of thread engagement was short and it was in a non-critical area if indeed a 5/16-26 thread is what is being used.
Both the UN threads and the Metric threads have 30 degree pressure angles (60 degree included "V" angle).
The British Whitworth standard threads use a 55 degree included angle rather than the 60 degree angle of the more common systems.
The common British Whitworth threads which are similar to the above 5/16 inch threads mentioned are the BSW 5/16-18 and BSF 5/16-22, neither of which will mate with the common fasteners used by the US or Metric system.
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Britsh Standard Cycle thread was 26 tpi. for all sizes. The Redditch, UK built machines all used BSC thread . It looks like the manufacturer in India did the same, at least till mid 1994 on the components I checked.
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I learn something new every day. :)
Leave it to those crafty Brits to invent a special thread just for motorcycles. :D
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It wasn't just for motorcycles. The threads were called British Standard; fine threads BSF and the coarse threads, BSC. All Brit stuff, Cars, motorcycles, airplanes, etc. used these threads until about the late 60s they started to convert to metric. A lot of stuff built during the conversion stages of several years, would have a combination of the two threads, that is British standard and metric. Of coarse, the spanners were different than anything else, too, and the BSF and BSC spanners were different, too!
Fun times working on Brit bikes and cars in those days.
Bare
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I think your getting British Association and British Standard mixed. All British Standard types had the same head sizes. British Association or BA was for smaller sizes less than 1/4 inch and had its own wrench sizes. There were fine, course, amd cycle thread sizes in the British Standard. It took me a while to get all the taps & dies for all these. The UK did go unified for a while basically using fasteners the same as what was used in the USA but there were hold outs that didn't change over till the metric system became standard.