92' YAM RXS100. Oil light stays on until 5th gear.

[Fimez]

Before i did any miles on the bike 99% of issues were solved for its MOT. This included just re painting the oil pump side cover and clutch side cover, i took the pump out, and refitted it without touching the adjustments. (And bled it)

A few fuel tanks later and i get the oil light coming on just in 1st and second gear, just flickering, it gets worse until today were it stays on until 5th gear at about 60mph. The engine runs absolutely fine, throttle response is exactly the same as before the issue came up, never leaked oil and its still got about 1000 miles worth of 2 stroke in it..?

There is ZERO mention of the oil level sensor or anysort of sensor in the manual of which is the most comprehensive one available.

Obviously i don't want to F around and find out but it seems to be getting a perfect amount of oil. I even foolishly revved it to 10 500 rpm and held it there for 15 seconds or so on the way back. Absolutely no sensation of lack of lubrication. And this is when the oil light holds totally solid until 5th gear?

Im no mastertech but i think this oil light is full of it.

[stinkwheel]

It's not an oil pressure light like on a 4-stroke, it's a level switch to tell you if the oil level in the 2-stroke tank is getting low.

So if the level is visually fine, yes there's a problem with the switch or the wiring between the switch and the light.

On your bike, power is supplied to the bulb which then goes to the switch. When the switch is in a "low oil" state, it makes a connection to earth and the bulb lights up. When it is in a "high oil" state, it is an open circuit and so stays off. It also has a connection with the neutral light which as I recall on most of these bikes, makes the oil light come on when the bike is in neutral to confirm the bulb is working.

So. It might be a faulty switch.

It could also be a break in the wire between the bulb and the switch intermittantly shorting to earth (ie touching the frame or another metal part). One thing that occurrs to me is that it is easy to trap a wire under the plastics and damage the insulation, especially if you've had bits off painting them.

It could be a short on the bulb holder in the instrument panel, I've seen this happen before if the holder pushes through a bracket which has some exposed metal on it. Test this by pulling the bulb holder out of the panel and seeing if the problem goes away.

There could also be a problem with the neutral switch, does the neutral light also stay on when it shouldn't? This is the only place where the gear position has any bearing on the oil light.

The switch should be easy to test. With a multimeter set on resistance or continuity, disconnect the oil level switch connector. It has three wires. If the sensor is immersed in a full tank of oil, there should be an open circuit (high resistance, no continuity beep) between the black on red and the black wire. If the sensor is uncovered, there should be a closed circuit between these wires (low resistance, continuity test beeps).

I should add, if there is sufficient oil in the tank, the light being on is of no relevance other than indicating there is a fault with the light. Just don't run out. It makes sense to check the oil every time you fill up.

For what it's worth, I'd put my money on there being a trapped wire and the vibrations of the engine when you're in fifth being enough to rattle it away from wherever it's shorting out.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[stinkwheel]

I should also add that if the oil ight comes on on a 4-stroke bike, stop the engine immediately and don't ride it again until you have found out what the problem is. They mostly have a pressure switch (there are exceptions, Yamaha diversions, I'm looking at you) and if it's come on, it indicates the oil pressure has dropped to a dangerously low level and engine damage is already happening.

It could also be an issue with the switch or wiring but it's not worth taking a risk.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Mysteriass]

One of the last two strokes left on the road...

And we test the 2T pump is working by revving the engine hard enough to see if it seizes.

2 strokes are too good for this world.

I'll say a little prayer for all their tortured souls. Lord have mercy.

[Fimez]

[Fimez]

[A100man]

[Rob Fzs]

probably dodgy sensor, you can get a whole tank for bugger all off ebay

these bikes are basic, there's no pressure switch or anything, i got a fucked one that would do at least 50mph with 60psi compression that i sorted by changing the rings on a mates doorstep
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'00 Aprilia RS50 > '92 Honda CG > '99 Yamaha Fazer > '91 Yamaha RXS > '79 Suzuki X5 > 01' Honda Cg > 07' Honda Cg > 82' Kawasaki Z200 > suzuki gsxr 400 gk73a > honda vfr 400 NC30> Yamaha RD350 YPVS F2 > Kawasaki ZZR 600 D1 > Yamaha TZR 250 2MA >Suzuki TL1000R > Yamaha TDR250 > Honda 929 blade > Suzuki SV1000 > Honda H100
Mod 2 Passed 09/06/2011

[Fimez]

[stinkwheel]

Check it doesn't have water in the tank too, that would sink to the bottom and could play hobb with the sensor.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Fimez]

[Fimez]