BSA A65 T oil pressure gauge vs warning light switch.

After the first test ride on this rebuilt machine raised some doubts regarding the oil pressure, I decided to swap between the warning light and the pressure gauge. If this machine had only used the standard fitment warning light and switch, which went off as soon as the engine was started, and stayed off even with a hot, slow idle, there would have been nothing to worry about!

[@TheRealCreepinogie]

Interesting. I just bought two A65 Lightnings, both needing work, for $250 each and am thinking of getting a gauge. I run them on my Halreys but they are more for the purpose of knowing the pump is working rather than the rider worrying about what their reading.

[@bakeredwards]

For cars, I always like to see a delay on the oil light coming back on. I've not had my A65 project running yet though.

[@paullacey2999]

Thats a lovely old BSA.

[@wdhewson]

I think Bourdon tube gauges are most accurate mid scale and least accurate at the lowest end.
Also, at one point i believed idiot lights replaced gauges due to cost savings, but it may have been to avoid "interpretation" problems and related worry, just as we're experiencing.
The pump's worm drive means slow pump revs and even slower if it's off the cam end. I forget if it's cam or crank driven.

[@paulhenshaw4514]

I agree re. the gauge / warning light thing. the oil pump drive is taken from the end of the crank, but there is a reduction in the drive worm gears.

[@garethlipyeart6520]

my tr7v has the light and gauge combined same issue hot and idling lucky to see 10 psi manual says 20/25? went to remove the orpv barely more than finger tight lol and i seperated the 2 halves without a spanner lol, so now fully torqued to 20 ft pounds,c what happens, there r some dodgy oprv out there with sloppy threads and wrong length springs lol just bought a new one from srm alledgedly the dogs nuts,dodgy pattern parts made in the east total crap most off it even lf harriss have a lot to answer for

[@hermangibbs8163]

Thank you for your attention to detail. I Thought SRM was the god of all oil pumps..hi.

[@paulhenshaw4514]

Thank you!

[@4speed3pedals]

I tried running an oil pressure gauge on my 68 Bonneville. I went back to the light after the vibration killed 2 brand new gauges. I never did get to try out an oil filled (for dampening) gauge.

[@britironjon7635]

I fitted oil pressure gauge to my oif triumph a few years back had same issue done exactly same test as you did in end refitted the oil light oil switch still running strong to day oil pressure gauge to distracting nice work

[@paulhenshaw4514]

Thanks, I totally agree!

[@Richard-pe4cx]

just like a ammeter

[@andytheflyer]

.......all the while not burning yourself on the exhaust!

[@markpedwell1250]

My 1968 A65 has no light or gauge which is a worry!, is it possible to fit one ? The engine is being rebuilt and I'm not sure if I trust the old pump 🤔

[@paulhenshaw4514]

Swings and roundabouts - if there is no light or gauge, there is either less, or more to worry about depending on your point of view. I have never tried converting an earlier engine to have either, so I don't know how it might be done, but probably possible.

[@rampakeshbharat1938]

I think the oil pressure switch comes on between 3 and 11 psi...

[@paulhenshaw4514]

Yes, 7 lbs, I believe.

[@satanssurfer5965]

Do you trust that pressure gauge?

[@paulhenshaw4514]

I am not sure, but I know I don't like it!

[@thegreatdandini8121]

Don't you have to bleed a capillary gauge or else all your doing is squashing a big bubble of air .

[@paulhenshaw4514]

Pressure is pressure, whether in liquid or air.