Oil light flash - mystery

Can anyone shed some light on this mystery:
The bike is the moped in my sig....

Yesterday, I got home and noticed the oil light flashing at tickover, so I
left it to cool, then checked and topped up the oil. Sorted; no flashing.

Today, I get home, oil light flashes... goes away at about 1700rpm.
I let the bike cool (at least an hour), then checked the oil again. The
oil level is fine.

This only seems to happen when the engine is hot.
Switching the lights off has no effect.
Goes away at about 1700rpm.
No blue smoke, no matter what revs.
No leaks.
Fires up first time - almost before the button is pressed.

Any clues?
--

Cheers!
Fr Jack
96 Tiger (sold - to be collected),
90 CB450DX (The Moped)
FRJACKUKRM AT GMAIL DOT COM
skype: fr.jack (without the dot)
We'll open up your eyes,
just to check that you're asleep, again

 

Fr Jack emerged from their own little world to say

loose wire, poor earth, fucked sensor

solution: black tape over the warning light

 

Wrong grade oil or crap oil quality? Oil pump on its last legs?

JB

 

Oil pump less than perfect, leading to low pressure (which is what the
light's normally telling you) especially when the oil's all hot and
thinner.

--
_______
..'_/_|_\_'. Ace (brucedotrogers a.t rochedotcom)
\`\ | /`/ GSX-R1000K3
`\\ | //' BOTAFOT#3, SbS#2, UKRMMA#13, DFV#8, SKA#2
`\|/`
`

 

I bloody hope not.......
--

Cheers!
Fr Jack
96 Tiger (sold - to be collected),
90 CB450DX (The Moped)
FRJACKUKRM AT GMAIL DOT COM
skype: fr.jack (without the dot)
We'll open up your eyes,
just to check that you're asleep, again

 

Hmmm.. too thin....mebbe.

What grade do supernightmares use?
--

Cheers!
Fr Jack
96 Tiger (sold - to be collected),
90 CB450DX (The Moped)
FRJACKUKRM AT GMAIL DOT COM
skype: fr.jack (without the dot)
We'll open up your eyes,
just to check that you're asleep, again

 

The electrics are fine... all the time..so not sure...

I hope that's all it is.. if so

May be deployed.... or JFII
--

Cheers!
Fr Jack
96 Tiger (sold - to be collected),
90 CB450DX (The Moped)
FRJACKUKRM AT GMAIL DOT COM
skype: fr.jack (without the dot)
We'll open up your eyes,
just to check that you're asleep, again

 

Could also be a clogged filter, clogged oil strainer screen on the oil
pump pickup, stuck oil pressure relief valve, knackered oil pressure
switch, worn bearings.

I googled and found...

I'd check the oil pressure relief valve, if it works the same way as the
CB500T, I've read that those can stick if the engine is run low on oil
in the link below.

http://www.thefang.co.uk/cb500tips.htm

 

Nobody seems to have suggested the correct answer - the engine is worn out.
Put a heavier grade oil in and forget about it for another few years.

 

Maybe not, it may just be a case of doing the maintenance tasks the last
owner forgot to do. It's an old design of engine, and should be
maintained as such.

 

Deary me. No worn out engine runs without smoke. That's the "Worn out" part
in action, the pistons/rings/bores/valve seals wear and allow oil into the
combustion chamber. He stated there is no smoke and IIRC it's fairly low
mileage - 60k on one of those lumps before any wear like that creeps in,
unless badly serviced and thrashed.

Have you tried changing the oil filter? Cheapest place to start.

Neil

 

Apparently, they may have two oil filters (so I read). One of which
almost never gets cleaned and can cause low pressure.

 

10/40

 

OK, low oil pressure. Shagged oil pump most likely.

 

oil pressure switch would be my favourite place to start

 

Muck says...

If it's like the 250RS then there's an oil screen that never gets
touched. It requires removal of the clutch casing to get to it, so no-
one ever bothered.

 

Trevor says...

And mine, I've seen them fail before, giving false readings. You may
find a pattern car one does the job for a fraction of the cost, just
make sure the pressure range is correct and whether the fitting is
tapered or not.

 

Hmm... better grab a HBOL, or somesuch, so I know what I'm looking
for........

I looked at the oil I used to top up, yesterday, it is 15w30... Is there
much difference?

Oh there's cheap 20w50 in ASDA for £3/5L. would I kill the bike using that
grade, regardless of price?
--

Cheers!
Fr Jack
96 Tiger (sold - to be collected),
90 CB450DX (The Moped)
FRJACKUKRM AT GMAIL DOT COM
skype: fr.jack (without the dot)
We'll open up your eyes,
just to check that you're asleep, again

 

Fr Jack says...

Use pikey oil and expect pikey performance from it. Car oil is fine in a
car, where it revs lower and doesn't have a gearbox and wet clutch to
contend with. Stop being a fucking pikey and do something properly for
once.

I wouldn't put a £3 oil in a fucked old car that I used locally, let
alone a bike I expect to get me 100 miles each round trip per day. It's
meant to take a 10W/40 for a start.

 

Lozzo emerged from their own little world to say

or a bike with a dry clutch