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WARNING! Triumph Oil Pressure Switches

24744 Views 40 Replies 19 Participants Last post by  Landon
Hello fellow JJers. I have been reading this thread for some time and am concerned about the advise given for Triumph oil pressure switches. The problem I see is that some JJers are advising other members to install the wrong type of sender or adapter for an oil pressure gage. First off DO NOT use a tapered thread oil pressure sending unit or a tapered thread adapter for an oil pressure gage. Triumph oil pressure switches are a straight thread, not tapered. If you use a tapered oil pressure switch then there is a good chance you will crack your timing cover. When I was a Triumph mechanic back when the factory was on strike we could not get many parts. Only what was on the shelves at the distributer. Once that supply ran out we had to make due with what we had. I can remember my father taking an American made automotive type sending switch chucking it up in a lathe cutting a shoulder and turning the straight threads.
I hope my advice opens up the doors for discussion so this problem can be corrected.
Old Codger
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I'm dragging this thread back up as I have a question relevant to this thread so I'd like to keep info here to make searches easier.

I have a new, aftermarket timing cover fitted to a '73 t140v and I need to get a blanking bolt to plug where the oil pressure switch would go.

My original timing cover had the 1/8" NPS bolt but the new cover uses a 1/8" NPT Thread.

I need a simple short bolt to thread in there and am wondering if sucha thing exists. I can find nothing locally so I'm hoping for a Triumph part number perhaps.
E9526- 70-9526- Blanking Plug
Thank you!

Now, is that part number 1/8" NPT?

I tried finding a small socket head 1/8" NPT plug and can't find anything around here so I'll have to order that Triumph part next time I do a parts order.
Yeah its 1/8 npt... Allen head or square head one from your local True Value hardware store.. I always tape them, and dont over tighten and I have never had a problem...
Thanks again. I actually can't believe I've had such a hard time finding a stupid little NPT plug here so I'll have to order that Triumph part.
I managed to find a1/8" NPT socket head plug. How far in should it thread before it starts to get resistance?

I can thread the 1/4" long plug in maybe 2/3 of the way in before things start to get tight. I realize that is the nature of a taperd pipe thread. I apologize for asking such a rudimentary question, but I don't want to crack the timing cover.

This is the timing cover I'm using with the 1/8" NPT. You can see why I'm leary of cracking it.
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If your going to have that much cash in that motor, then you should think about a switch, or gauge for sure.. I use the switches.. Gauges are a little over kill... If the motor was rebuilt right, it will have oil pressure... Like stated before, if you are going to put a large chunk of change (judging from the looks of that cover I would say you are).... Then put something other than a plug in it...
I thought the way you're thinking now. Plug or bolt would be temporary until I find a guage or something. I didn't want a switch to keep things clean (cosmetically and electrically) but I am starting to rethink things. Once the build is done, before final electrical work is complete I may wire in a switch. I'd prefer a guage but you can only see them while at a light or before you ride. I may do that until I make a nice mount for a guage near the bars.
True, but how many engines are actually built right? I'm sure you've had your fair share on repairing other peoples F/ups. Just recently we recieved a Trumpy for a few repairs and modifications. The customer asked us to fit an oil gauge and we did. On start up, there was zero oil pressure. Checked the gauge, worked fine. Pulled off the timing cover and the oil seal was ragged out. The engine was rebuilt using lots of new parts, including timing gears, oil pump etc. Very clean job. But it looked like someone had used their palm to drive the timing cover on and the seal must have caught the crank.
Lucky the bike wasn't ridden much since the rebuild. We caught it just in time. This is why we like to use oil gauges.
I bought my motor as rebuilt but when ripping the primary apart to fit a belt drive, I noticed no clutch nut washer and the rotor nut lock washer was beat to shit. There was the odd rounded off nut or ratty fastener, as well as a bent stator stud. When rebuilding you'd think putting in the appropriate washers and some new fasteners where required would be common practice but I guess not.
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