Unofficial Royal Enfield Community Forum
Royal Enfield Motorcycles => Vintage Royal Enfield => Topic started by: FinRoyal on October 24, 2013, 08:54:33 pm
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Hi
I have 1959 Chief with 120mp/h Stewrd speedo, but it's missing that adapter to use smith speedo cable. Anybody have some to sell or send me pictures with measurements of that part to make my own copy.
royal.enfield(AT)pp.inet.fi
BR
Pasi
Finland
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Your best bet is to contact Hitchcocks. They may be able to help you with this. ERC
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The part resembles an aircraft tube type fitting. I don't have a camera to take pictures but I can describe it. I will have to use the inch system since that was how it was made. It is 1.130 inch long. It has a 15/16 inch hex (actual 0.925 inch) in the middle. Both ends are male thread. The thread for Stewart Warner end is 3/4 inch X 20 thread per inch. The Smiths end is 1/2 inch X 26 thread per inch (actual diameter is 4.65 inch). The hex portion is .246 inch thick. The Smiths end has a step that is .630 inch in diameter and .174 inch thick then the threaded end portion is .371 inch long. The Stewart Warner threaded end is .308 inch long. There are 2 steps inside the body with 3 different diameters. Starting on the SW end the diameter is 1/2 inch and .380 inch deep. The next step is .375 inch in diameter and the step is .530 inch from the SW threaded end. The diameter on the Smiths end is .273 inch.
There is a spindle that fits inside with the SW square drive on one end and the Smiths slot drive on the other. The spindle is 1.134 inch long overall. The SW drive end is .102 inch square and .395 inch long there is a stepped portion in the middle of the spindle that is .343 inch in diameter and .127 inch thick. The Smiths end is .274 inch in diameter and .497 inch long. The slot is .127 inch wide and .395 inch deep. The body is made of brass and has a plating on the outside of what may be zinc. The inner spindle is made of steel.
I hope this is a help to you. Sometimes you can find the Indian Enfield SW speedometers on flea-pay and they still have the adapter in place but not very often. The 120MPH speedos were used until the 1958 model year then they used the 150 MPH speedo but the drives were still the 8:3 ratio which is odd for the Smiths units but common on the American made bikes. These Smiths drive gearboxes are also hard to find now since they were only made for the American market and many were used till they were broken.
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Since Rotor did the heavy lifting; I thought I could at least post the pictures. You can see that mine is affixed with two small allen screws because the threads are stripped in both the speedo head and on the adapter. In one picture I added an Amal carburetor part because it looks suspiciously like said adapter. I have seen one other adapter and it was stripped like mine, so it may not be an uncommon malady.
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Thanks,Rotorwrench,for posting all of the dimensions,and thanks,Tom,for posting the pix...very helpful!