Author Topic: Oil tap  (Read 474 times)

0 Members and 1 Guest are viewing this topic.

courtney

  • Royal Star
  • ***
  • Posts: 129
    • View Profile
Oil tap
« on: 13 August, 2023, 14:28:27 »
I have a 1936 B2 and wanted to fit an oil tap to the fuel/oil tank as mine doesn't have one. Can anybody please advise as to what thread size it is on the oil tank for these bikes?

Many thanks in advance
1965 BSA C15
1970 BSA B25 (US spec.)
2004 Aprilia Tuono

militaryron

  • Blue Star
  • **
  • Posts: 63
    • View Profile
Re: Oil tap
« Reply #1 on: 13 August, 2023, 16:52:50 »
Usually they are 1/4 BSP. (the thread is about 1/2" diameter). But I'd consider a tap in the oil line as a dangerous thing.  Ron

Y13 Alan G

  • Royal Star
  • ***
  • Posts: 142
    • View Profile
Re: Oil tap
« Reply #2 on: 14 August, 2023, 10:54:23 »
Hi Courtney, I have a few pre-war BSA's including a 1932 G32/12 986 side valve Vee Twin & a 1937 Y13 750 OHV Vee Twin. The G32/12 operates on a total loss oil system and has an oil tap under the oil tank in the main petrol oil tank which is switched on when using the bike. If it is left on the oil drains from the tank to the sump, not a good idea. My Y13 has a fully closed oil system but if not used for a few weeks the oil used to drain from the the oil tank to the sump. It has a valve that is supposed to prevent this but since it was built in 1937 and although I replaced the ball in the valve the seat is obviously worn as it didn't stop the oil draining into the sump. So I fitted a large tap just below the oil tank to prevent this. All you have to do is remember to turn the tap on before starting the bike otherwise you will have to drain the sump every time you want to use the bike. It will not start, or perhaps not even turn over with a sump full of oil. Hope this helps.

courtney

  • Royal Star
  • ***
  • Posts: 129
    • View Profile
Re: Oil tap
« Reply #3 on: 14 August, 2023, 22:18:18 »
Hi Alan, thanks for the reply. That's exactly why I wanted to fit one. Most I've seen online seem to have had one fitted at some point for that reason, but it'd also help if I needed to remove the tank to avoid having to drain the oil. Can you confirm, as Ron says, the tank thread is 1/4", or is that just the pipe size?
1965 BSA C15
1970 BSA B25 (US spec.)
2004 Aprilia Tuono

militaryron

  • Blue Star
  • **
  • Posts: 63
    • View Profile
Re: Oil tap
« Reply #4 on: 15 August, 2023, 05:20:24 »
If you have a Vernier or some other means to measure across the thread in the tank and confirm it is 1/2"......It will then confirm the tap size as 1/4 BSP.  Ron

Y13 Alan G

  • Royal Star
  • ***
  • Posts: 142
    • View Profile
Re: Oil tap
« Reply #5 on: 15 August, 2023, 09:47:00 »
Hi, I hate to state the obvious but make sure the inside diameter of the tap is the same as the inside diameter of the oil pipe. Most taps are for petrol and only 1/4 inch inside diameter and your oil pipe is probably 5/16 inch inside diameter. Best of luck.