oil sending unit

[Big Auggie]

Since there's an idiot light for it I assume there's a sending unit somewhere signaling when the oil pressure is low. Mine comes on once in awhile for a few seconds. I'm guessing loose wire or bad sending unit. Wouldn't think it'd be the pump at 78K. So where is it?

[Big Auggie]

OK, I finally found some old threads that said it's not a pressure warning but a low oil level indicator. That is making me think even more that I have a wire grounding out somewhere. Where is the wire for the oil sensor routed? I'd just as soon start from the bottom rather than pulling the instrument cluster out first.

[Flyinfool]

The oil level light will sometimes come on during hard acceleration. The oil sloshes to the rear of the engine and the sender sees low oil.

[GaryZ]

What he said . . .

 

I regularly saw the oil light when hammered down on my '85 with the Vmax cams

[videoarizona]

David, did you look in the 1st gen tech area for the electrical schematics? Once you find the sensor, should be easy to follow the wire and look for junctions. At the least, write down the wire colors and grab a flashlight and explore. I'm out of town can't check on my 89.

[videoarizona]

I think I found the sender. On left side. Just aft of the rear engine guard mount near bottom of engine should be the sender. It's mounted into the block with two screws/bolts. Has one black/red wire coming out of it. The diagram says it goes directly to computer... So probably runs up left frame rail... Then over to computer.

 

Let me know if you find it..

 

Could be in bottom of motor.. Can't tell

[retrostude]

If it doesnt come on once in awhile, you aren't riding it hard enough.

 

Sent from my SCH-I535 using Tapatalk

[yamagrl]

Here's the wiring diagrams http://www.venturerider.org/forum/showthread.php?42358-1st-Gen-Wiring-Schematics-1983-1993

[cowpuc]

Yep,, that oil sending unit is located on the underside of the engine, left side right next to the front exhaust header and in behind the oil filter mount.. Between the oil filter and the oil drain.. Its a little flush mount critter with two small bolts holding it in place and one small wire leading to it.. Its fairly easy to test because all it really is is a float switch of such - has one wire leading to it that I believe is provided voltage from the Monitor (cmu) itself. Thinking that when the float switch makes (closes) that it completes the circuit and bingo - light comes on.

Fairly common for em to flicker - especially if your on the throttle and running close to the bottom line in the site window - on my high mileage scoots as the motors got worn a little I would use the ol "hit her hard and watch for the light" to know when its was add oil time - worked great but important that the sending unit work properly..

Be very possible for that sending unit to be cruded up sticky and not getting full movement - flicker or even stick on.. If you pull it - drain the oil first or ya instantly got a real mess..

[camos]

Its fairly easy to test because all it really is is a float switch of such - has one wire leading to it that I believe is provided voltage from the Monitor (cmu) itself. Thinking that when the float switch makes (closes) that it completes the circuit and bingo - light comes on.

I would bet the oil sensor is not as sophisticated as a float switch. The single wire is most likely hot and when the sender switch is covered with oil the circuit is closed and when the oil level is low then the movement of the bike will make the oil surge and break the circuit. There would likely be significant issues with engine crud if an actual float was used.

[Prairiehammer]

I would bet the oil sensor is not as sophisticated as a float switch. The single wire is most likely hot and when the sender switch is covered with oil the circuit is closed and when the oil level is low then the movement of the bike will make the oil surge and break the circuit. There would likely be significant issues with engine crud if an actual float was used.

 

I believe it is a magnetic reed switch with a floating magnet. Here is a picture of a more modern Yamaha oil level switch (almost a cutaway look) showing an obvious ring surrounding a center armature. The Venture and other Yamaha products has a visually similar oil level switch, albeit several holes (second pic) instead of the more modern slots.

 

[Venturous Randy]

Sometimes in the past when I changed my oil and it was drained, I would turn the ignition switch on and see if the oil level light icon came on. It always did.

Randy

[camos]

I believe it is a magnetic reed switch with a floating magnet. Here is a picture of a more modern Yamaha oil level switch (almost a cutaway look) showing an obvious ring surrounding a center armature. The Venture and other Yamaha products has a visually similar oil level switch, albeit several holes (second pic) instead of the more modern slots.

It is more sophisticated than I thought. Good thing you told me before I actually made a bet.

Having holes rather than being more open would probably cut down on false positives from surging.

[Big Auggie]

It was time to change the oil for winter storage so I pulled the oil sensor unit. I'm planning on running some carb cleaner in the holes in case there is some gunk in there. Any other suggestions?

[Big Auggie]

Took it for a short run and no low-oil warning light! The real test will come later when I can get in a 100+ mile run.

 

When I ran the carb cleaner through the oil sensor unit there didn't appear to be any gunk pouring out.