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Discussion Starter · #1 ·
was on my way home from riding last night and the sun set about 5 minutes before I got home, but becuase it was dark, I noticed that the LED I used in the Oil Lamp Socket was flickering to the rpm of the motor...for example at idle, the LED would illuminate at every stroke.



What's going on? My guess is that the LED's require so little power that there is transient voltage through the oil circuit causing the LED to flutter?
 

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Discussion Starter · #3 ·
I believe the 79 oil pressure switch is linked to the rear brake light?


That would be correct if the modulue was still plugged in. I have disconnected that module/your-brake-light-bulb-is-out-so-illuminate-the-oil-pressure-light dummy system!!



Just found the flickering odd. Also it would appear to be a waste of power that might not be recognized in a bike that is running bulbs. The bulb would not have enough voltage to be illuminated. Back to the question of why does the oil lamp flicker to the frequency of the cylinders firing?
 

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Just a guess but the Neutral and Head light/indicator bulbs/circuits etc are basically in an on or off state.The oil pressure sender I think has a constant but varying voltage and resistance.



Also the Oil pressure sender circuit is different inasmuch as it it not grounded using a green wire but I'm not sure how much effect that may have.





http://globalcxglvtwins.hostingdelivered.com/viewtopic.php?f=8&t=176
 

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the oil pressure switch is a simple on off affair

At igniton on the contacts are held closed by a spring which closes the circuit to

ground and the light ( bulb or led ) glows

and when the motor runs, the oil pressure lifts the contacts and and the lights go out



However, it is possible for pressure to be at just the right (lowish) level to allow the

contacts to close up or bounce on and off slightly.

the slightest touch will light an led where a bulb wouldnt have time to warm up

Also I doubt the oil has a steady continuous flow and is somewhat pulsed

by the behaviour of the motor. this can add to the symptom.

Add this to the fact that LEDs need much less current to start to glow than an incandescent bulb,

around 10mA compared to say 180 mA for a bulb so the slightest contact could show on the LED



the question is:

Is there problem?

thats the tricky bit

Its hard to say for sure without using a pressure gauge

With a hot motor, oil pressure at tickover can be pretty low so it might

be just because the led circuit is more sensitive

but any oil lights bulb or LED when running would concern me.



I may stick an led on mine tomorrow just to see what happens
 

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However, it is possible for pressure to be at just the right (lowish) level to allow the

contacts to close up or bounce on and off slightly.

the slightest touch will light an led where a bulb wouldnt have time to warm up

Also I doubt the oil has a steady continuous flow and is somewhat pulsed

by the behaviour of the motor. this can add to the symptom.




I think this is the most likely thing Reg.Also as they are most likely the same age as the bike they may be a bit twitchy?
 

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While it's possible that oil pressure SWITCH has some internal leakage (an ohm meter should show that) there's no reason the LED should be coming on. I'd look a bit deeper, the last thing you want is to be running low on oil pressure.
 

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Discussion Starter · #9 ·
Just a guess but the Neutral and Head light/indicator bulbs/circuits etc are basically in an on or off state.The oil pressure sender I think has a constant but varying voltage and resistance.



Also the Oil pressure sender circuit is different inasmuch as it it not grounded using a green wire but I'm not sure how much effect that may have.





http://globalcxglvtwins.hostingdelivered.com/viewtopic.php?f=8&t=176


So in saying that the oil pressure switch is not grounded via a green wire, are you pointing to the case ground possibly being faulty?
 

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Discussion Starter · #11 ·
While it's possible that oil pressure SWITCH has some internal leakage (an ohm meter should show that) there's no reason the LED should be coming on. I'd look a bit deeper, the last thing you want is to be running low on oil pressure.


I am not an electrician by no stretch of the imagination, but I do have a nice Multimeter...how would I diagnose internal leakage? I am guessing this would be similar to insulation resistance testing for a power cable to measure current leakage? I think they call it a megger test? Talk to me Marshall! I would like to sort this out!! If the insulation and case properties of the sensor are good, then I could expect in a perfect world...infinite resistance correct? Leakage would show up as low resistive properties--right?



Maybe I need to trace the entire wire for that circuit as the old wiring may have some leakage in the insulation?
 

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So in saying that the oil pressure switch is not grounded via a green wire, are you pointing to the case ground possibly being faulty?


No.Just mentioning it as it's a different kind of circuit than the others which may or may not have an affect on the situation.I think Reg has nailed it.
 

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Rick

I dont know for sure why the led is flickering

I do know an led will be more sensitive and respond more rapidly

then a bulb cos thats the way they are

the engine block is one big ground, or should be, so no extra wires needed



As before I'm kind of thinking out loud and

Maybe the led because of its sensitivity is picking up inconsistencies

in the system that a bulb wouldnt

Maybe the oil pumps struggling due to wear and perhaps clogged filter

Maybe its just general wear and tear, its hard to say.



What it like when cold ie thicker oil?

Testing with an oil pressure gauge would help to see if alls well or not

An electronic oil pressure gauge is a project I've had in mind

for ages and never got round to mainly because finding a compact sender

unit was tricky.



I'm here tinkering today and

I'll put an led on mine later and let you know what it does
 

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Discussion Starter · #14 ·
also keep in mind that the flickering is so faint that it can only be seen in the dark. She runs great, but I just found it very strange. I hope Reg is wrong. how big of a deal is it to take out the oil pump & check it, clean it, etc?
 

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It's what I'd call a middle sized job.It's worth doing just in case as the oil pump strainer can get clogged with debris especially if the PO has been sloppy with RTV/Gasket sealer and the sump can get sludge in it.



You would most likely need a new front engine cover gasket or make your own,



http://globalcxglvtwins.hostingdelivered.com/viewtopic.php?f=10&t=256



It's worth making a little home-made kit as it saves money,time and frustration in the long run.



Also worth getting one of the cheap O-ring kits as well,



http://cx500forum.com/index.php?/to...l__+harbor++freight__fromsearch__1#entry78429



Biggest PITA is getting the Mech fan off.I don't have that problem with my Efans.Two bullet connectors and my rad and fan are off and the front of the engine is clear to work on
 

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Rick

just to be clear

I'm not saying its anything

the fact is, I dont know and as I said it may be normal behaviour

that the sensitive led shows up and thats all

Hopefully that guess is the right one



I've just made up the led oil ight and will patch it in to the

exisiting bulb circuit in a minute and I have to take the bike out

for fuel later so will see how it behaves

I've potted it down into a black tube so I can hopefull see any faint glimmers

even in daylight.

its under the tacho

 

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Discussion Starter · #17 ·
Rick

just to be clear

I'm not saying its anything

the fact is, I dont know and as I said it may be normal behaviour

that the sensitive led shows up and thats all

Hopefully that guess is the right one



I've just made up the led oil ight and will patch it in to the

exisiting bulb circuit in a minute and I have to take the bike out

for fuel later so will see how it behaves

I've potted it down into a black tube so I can hopefull see any faint glimmers

even in daylight.

its under the tacho



I really appreciate the extra effort Reg. I hope we can learn something from it. Maybe we've latched onto a method to check the oil pump/screen/performance etc. I am thinking I need to check the oil pump at some point...sure beats a starved motor.



Your dash is awesome Reg...I like the air freshener.
 

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Ok its in and working alongside the stock bulb setup

I used a high intensity led and the short vid is with a cold engine

so I wouldnt expect much if any differences

Later I'll go out and thrash it about bit and see what happens

My old lump is far from a pristine example BTW

but the oil and filter are only about 200 miles old

be interesting to see how it behaves



[media]http://www.youtube.com/watch?v=Qm8fE1EkUIk[/media]
 

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Right

Been out for fuel and got the bike hot enough to turn on the fan

(which does still tend to come on too early) and the bike will run

hotter on a longer run and even light the bottom clear red led at times



Its probably near a normal knockabout running temp though and so far

theres no sign of the led glowing at all.

Its too early to say with any degree of confidence of course but

will keep an eye on it

In the vid the bikes running and you can hear the fan

neither of the oil ligst are glowing at all

I patched on a few seconds of vid after I stopped the engine and you

can still hear the fan and see the two oil ights fully lit.

[media]http://www.youtube.com/watch?v=YHQ78L5e0Dg[/media]
 

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Discussion Starter · #20 ·
so the plot thickens. Thanks again for the testing there Reg...fantastic of you to do so, and so quickly.



I will try to get an oil pressure gauge inline and measure to be sure my oil pressures look good. Not too long ago some results were posted for a gauge, and I think the pressure readings were anywhere from 30-psi to 75-psi...does that sound right? Yet another reason to consider an Oil Pressure Gauge instead of a "ITS TOO LATE" Indicating bulb.
 
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