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Discussion Starter · #1 ·
I was wondering where on the motor i could tap in an oil presure guage.... every once in a while after a long ride <oil thinned down> i get a flicker of the oil lite at idle. Is this very common? It could be just a bad sending unit possibly? thanks for any help Mike
 

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Mike

You'll need to use the exisiting sender hole to plumb in a gauge

a tee peice would allow you to compare switch function aganst pressure



Whats your tick over speed?

I recall discusions on how some guys tried to get their CX to tickover at say 500

while others reckoned that slow a speed would reduce oil pressure alarmingly and possibly

cause premature wear in major bearings.



I'm in the second camp and set mine to about 1100

If yours is near that and you still get the oil light flickering then I'd say its

a cause for concern

It is possibly the sender but often suggests wear in major bearings I'm afraid



assuming good oil and its not running too hot and its also possible the pressure relief valve below the pump isnt seating properly

which would prevent the pump getting up to full working pressure
 

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If you haven't already a front end engine service would be in order.This means taking the front engine cover off and cleaning the sump area under the oil pump.Checking the oil pump service limits and cleaning the Oil pump strainer.Also whist off checking the oil sender unit is working correctly(See manual).

Also check the oil pressure bypass valve is operating correctly in the oil filter bolt and also that the oil pressure orifice and all associated O-rings and dowels are is in place and correctly orientated.



http://www.cmsnl.com/honda-cx500a-1980england_model16465/partslist/E18.html





Also check the 7v regulator and all grounds as it also feeds the Oil sensor,



http://globalcxglvtwins.hostingdelivered.com/viewtopic.php?f=8&t=257







If all of the above is checked and nominal and it still does it it can be a sign of worn big-end shells.If this is the case the bike should not be used until the engine is fully stripped and the crank shaft professionally checked and if ok new shells fitted.
 

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Discussion Starter · #4 ·
If you haven't already a front end engine service would be in order.This means taking the front engine cover off and cleaning the sump area under the oil pump.Checking the oil pump service limits and cleaning the Oil pump strainer.Also whist off checking the oil sender unit is working correctly(See manual).

Also check the oil pressure bypass valve is operating correctly in the oil filter bolt and also that the oil pressure orifice and all associated O-rings and dowels are is in place and correctly orientated.



http://www.cmsnl.com/honda-cx500a-1980england_model16465/partslist/E18.html





Also check the 7v regulator and all grounds as it also feeds the Oil sensor,



http://globalcxglvtwins.hostingdelivered.com/viewtopic.php?f=8&t=257







If all of the above is checked and nominal and it still does it it can be a sign of worn big-end shells.If this is the case the bike should not be used until the engine is fully stripped and the crank shaft professionally checked and if ok new shells fitted.
 

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Discussion Starter · #5 ·
Thank u both for the help!... This bike was bought a cpl months ago with 23k on it. I have cleaned the carbs, valve set, changed oil and filter i used 10w-40 castrol GTX. I have put 1500 miles on it in the last few weeks and it has run like a swisss watch
I just went and checked my idle... 1100rpm ... under the valve cover the heads were clean and shiny, a good indication of frequent oil changes... i'll hope for the best!! I'll clean the strainer and i have a snapon oil press. guage i'll use to give me a positive reading thanks again for the pointers

Mike
 

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With such a low mileage I would not think there would be a bottom end problem.More likely a wiring/sensor problem with the oil system.The correct idle speed should be 1100 rpm +/- 10%.Too low and the oil pump won't work correctly,too high and gear changes will be harder causing the gearbox to wear quicker and if stuck in traffic run the engine warmer than needed.

Even a low mileage bike at age can have faulty components like oil/temp sensors failing and or corroded wire connectors.Make sure the wires/connectors under the tank are all cleaned and corrosion removed.



It has been known for debris to block the oil pump strainer hence the front end service but I think your 650 is easier than my UK Cxs as it has a sump plate for access?
 

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Also check the 7v regulator and all grounds as it also feeds the Oil sensor,



Err, not really. The 7 reg is just for bikes with 7V gauges

the oil light circuit is quite simple



At ignition on

power goes to one side of bulb then on to the pressure switch for a ground.

If the engine is not running or you have no pressure,

the spring loaded contacts are closed

and the circuit is complete so the bulb lights.

When motor runs, the pressure builds and lifts the contacts apart

this breaks the circuit so the light goes out.



When we get the oil light on unexpectedly, we all hope its the sender but

they are generally robust usually its an indication something else.

As Shep says, at 23 thou you wouldnt expect major bearings to go south

unless some PO has been caning the arse off it and/or neglecting things

Sheps strainer suggestion is worth try as any restrictions here could

obstruct the supply



hope its something simple cheap and easy to fix !!
 

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Discussion Starter · #8 ·
I will need to get my hands on a manual soon... now i'm curious what oil pressure it should be carrying at road speeds also
 

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While on the topic. Is there a handlebar mountable oil pressure gauge we can get for our bikes?
 

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