Topic: Oil Light On after a quick ride...

[sh1bby69]

I have a 73 Honda CB 500 and after about 15 mins of riding on surface streets 45mph average the oil light will begin to flicker on/off and about 5 mins after its a steady light. I get home and after my bike has cooled I checked the oil level and its where it needs to be. Its currently using 20-40w non synthetic. I smelt the oil and I believe it has a hint of gas...not 100% sure. I've read it could be the oil sensor. Is that what you all believe it is? When the bike cools down the oil light is back off. Do you think wrapping the headers can contribute to it? I don't think it would...

Thanks

[MCRider]

I have a 73 Honda CB 500 and after about 15 mins of riding on surface streets 45mph average the oil light will begin to flicker on/off and about 5 mins after its a steady light. I get home and after my bike has cooled I checked the oil level and its where it needs to be. Its currently using 20-40w non synthetic. I smelt the oil and I believe it has a hint of gas...not 100% sure. I've read it could be the oil sensor. Is that what you all believe it is? When the bike cools down the oil light is back off. Do you think wrapping the headers can contribute to it? I don't think it would...

Thanks

As you may know the oil light has nothing to do with the level, but with the pressure. It would have to be nearly empty before the oil light would come on, if that were the only problem.

99 times out of 100 it is the sensor, residing behind your sprocket cover I think. If its not the sensor you may have bigger problems. How many miles?

IF you suspect gas in oil change it soon. (now). Do you turn your petcock off before parking? You should, SOP. I prefer to turn it off as I'm coming up the drive, to pull the float levels down a little before turning the engine off. Reducing the chance of gas getting into the cylinders that way.

[sh1bby69]

I have a 73 Honda CB 500 and after about 15 mins of riding on surface streets 45mph average the oil light will begin to flicker on/off and about 5 mins after its a steady light. I get home and after my bike has cooled I checked the oil level and its where it needs to be. Its currently using 20-40w non synthetic. I smelt the oil and I believe it has a hint of gas...not 100% sure. I've read it could be the oil sensor. Is that what you all believe it is? When the bike cools down the oil light is back off. Do you think wrapping the headers can contribute to it? I don't think it would...

Thanks

As you may know the oil light has nothing to do with the level, but with the pressure. It would have to be nearly empty before the oil light would come on, if that were the only problem.

99 times out of 100 it is the sensor, residing behind your sprocket cover I think. If its not the sensor you may have bigger problems. How many miles?

IF you suspect gas in oil change it soon. (now). Do you turn your petcock off before parking? You should, SOP. I prefer to turn it off as I'm coming up the drive, to pull the float levels down a little before turning the engine off. Reducing the chance of gas getting into the cylinders that way.

Thanks! The bike says 30k roughly. I try my best to remember to set the petcock in the off position.

As for the sensor, what should I do? Should I replace it or clean it?

[MCRider]

I have a 73 Honda CB 500 and after about 15 mins of riding on surface streets 45mph average the oil light will begin to flicker on/off and about 5 mins after its a steady light. I get home and after my bike has cooled I checked the oil level and its where it needs to be. Its currently using 20-40w non synthetic. I smelt the oil and I believe it has a hint of gas...not 100% sure. I've read it could be the oil sensor. Is that what you all believe it is? When the bike cools down the oil light is back off. Do you think wrapping the headers can contribute to it? I don't think it would...

Thanks

As you may know the oil light has nothing to do with the level, but with the pressure. It would have to be nearly empty before the oil light would come on, if that were the only problem.

99 times out of 100 it is the sensor, residing behind your sprocket cover I think. If its not the sensor you may have bigger problems. How many miles?

IF you suspect gas in oil change it soon. (now). Do you turn your petcock off before parking? You should, SOP. I prefer to turn it off as I'm coming up the drive, to pull the float levels down a little before turning the engine off. Reducing the chance of gas getting into the cylinders that way.

Thanks! The bike says 30k roughly. I try my best to remember to set the petcock in the off position.

As for the sensor, what should I do? Should I replace it or clean it?

The oil pressure measured by the sender (at least on a 750) is determined by the clearance of the cranckshaft main bearings. Assuming that is true with the 500 series, 30K miles is not enough to worry about. The sensor is so close to the oil pump on a 500, I may be offbase.

When the sensors fail, its an internal problem and replacing it is the only fix, AFAIK. 

[camelman]

I just had the same thing happen on a CB500 I had.  Whenever the engine heated up, then sensor would flicker.  I replaced the sensor, and all issues went away.  I don't remember if the oil level is above the port where the oil sensor screws in, but I seem to remember having to lean the bike over (you'll need a helper for that), and replacing the sensor that way.  I had just changed the oil, otherwise I would have gone the easy route and drained it.

Camelman

[sh1bby69]

Thanks everyone! So is replacing the oil sensor a pretty simple task?

[sh1bby69]

Also can I get a part number or if someone can direct me on where to get one. I've looked on ebay but they are all used. Would you have an issue on getting one from ebay?

[dave500]

its an oil pressure sender unit,take it off and go to you nearest decent auto parts place,compare it physicly to one they have,itll work ok.,its an on/off switch,set at a certain pressure,which isnt really critical,all engines need at least x amount of pressure at idle.and the switch will work as long as it fits under the casing.

[lrutt]

its an oil pressure sender unit,take it off and go to you nearest decent auto parts place,compare it physicly to one they have,itll work ok.,its an on/off switch,set at a certain pressure,which isnt really critical,all engines need at least x amount of pressure at idle.and the switch will work as long as it fits under the casing.

I'm not so sure that is the best recommendation. sending units are set to 'come on' at different pressures. Unless you know what the Honda one is set for you could get one that would be on all the time. I can't believe it would be that expensive to get the real thing from Honda. Did you happen to check bikebandit?

[MCRider]

Thanks everyone! So is replacing the oil sensor a pretty simple task?

It has a wire on it, attached by a small nut. Remove that. Then even though it is round, it has flutes cut in it which match up to a socket of the appropriate size. With the socket, or a pair of pliars/channel locks, the sender unscrews from a hole and there you go.

Reverse for replacement.

[johnrdupree]

Also can I get a part number or if someone can direct me on where to get one.

You can get OEM part numbers from the fiche on www.ronayers.com.  Unfortunately, it only goes back to 1975, but the 500 and the 550 should use the same part (BikeBandit has the same internal part number for both).  If that is the case, then the Honda number is 37240-P13-013 and their price is $23.00.  The cross reference on ronayers says that part was used as recently as 2006 in the CBR1000, and Googling it brings up links to Honda and Acura cars so it should be easy to find one.

Hope this helps.

~john

[sh1bby69]

Thanks everyone! Everyone on here has been great! This is my first bike that I've actually attempted to get my hands dirty in restoring. So I think I may go down to a auto shop to see if they have that part in stock.

@johrdupree Thanks for the part number. That is going to help out a lot!

[domer]

been down this road....

http://forums.sohc4.net/index.php?topic=75212.0

[sh1bby69]

Where is the oil pressure switch. I can't seem to find it...

[dave500]

behind the left hand chain cover.

[sh1bby69]

Thanks! I found it! Now I have a new problem. ill post a new thread to keep it specific.