Please inspect your oil pressure switch and timing cover before ordering. An oil pressure switch with straight pipe threads (like 60-3719) uses an o-ring, copper washer, or crush washer to seal. An oil pressure switch with tapered pipe threads (like 60-2133) seals with Teflon tape or anti-seize compound on the threads, sometimes an unnecessary o-ring is added. Straight threads are parallel to the flats on the wrench/spanner surfaces and the raised area above the threads, tapered threads are not. The differences can be easily identified with a machinist rule or other straight edge held up against the flat surfaces with the straight edge extending parallel to the threads.
Please be careful when installing, too much force will crack the timing cover or cause any existing cracks to spread. Triumph timing covers are interchangeable over a broad range of years and are changed for a variety of reasons so please don’t assume your motorcycle has the same timing cover it had when it left the factory back in the good old days.
The tapered thread oil pressure switch is a reproduction of the original Smith’s 5300/1/107 NPT 27 threads per inch, with a 7 psi switch point, as used on the 1969 Triumph twin cylinder models. This switch is also associated with part numbers 19-6504 and 60-1943, which were originally Smith’s 5307/05, with a 5 psi switch point.
Although the Triumph 500, 650, and 750 parts books show the 60-2133 NPT oil pressure switch, It will be necessary to measure the outside diameter of the existing switch to verify whether it is a tapered thread (NPT), or a straight thread (NPS), which we offer under part number 60-3719. Using a digital caliper and measuring the threaded section of the switch in a parallel plane, it will be clear if you are replacing a tapered switch. Our measurements show approximately .405” diameter at the threads under the flats, tapering down to approximately .391” diameter at the bottom of the threads.
Since the early 650 unit timing covers are interchangeable with the later 750 models, this measurement is recommended to confirm the correct fitment of your oil pressure switch in the event the timing cover has been swapped for a different model year. The 1968 and earlier timing covers were threaded to 3/8”-26 TPI, and were only fitted with a blanking plug.
If when installing any oil pressure switch into a timing cover or crankcase, when undue friction is encountered, stop and evaluate the situation before damage results.
Please note: Due the nature of the product, we unfortunately do not accept returns on bearings, service tools or electrical components. Please be confident about your purchase before ordering. If you have questions, please contact us.
Read more about oil pressure switches on our blog: A Guide for BSA and Triumph Oil Pressure Switch Identification