oil passage not making sense

[Missile99]

It's not making sense to me, anyway.

The other day after riding for 20 miles or so the oil light flickered then stayed on steady. I shut it off and checked the oil, which was full and just changed 50 miles ago. After starting it up and hearing no noises I decided to limp it home, about 5 miles. No problems. The light goes off when the wire is pulled off the sending unit, so I believed there was actually a problem with flow. The bike sat for 9 years and I hadn't checked the sump strainer, so I decided to do it now and fix a leaky pan gasket and drain plug too. The old girl has gone 1000 miles so far since exhumation.

What confuses me is the oil passage that has an o-ring at the bottom that appears to seal against the pan gasket. In the pictures you can see the part of the gasket that covers the hole on the pan, and in turn appears to seal off the passage above the o-ring. The gasket is bowed toward the pan and has a tear in it at this spot. Could this have been the problem? I don't understand how the oil flow works yet. In the flow diagram that I saved while searching, it looks like this passage could be overflow. What is the purpose of the o-ring in there? (Trying to upload pictures) Any advice is appreciated.

I intend to order a new Suzuki filter, pan gasket, a gauge from renobruce and this mystery o-ring and see what happens. If the low pressure gauge shows good then I'll pull the sending unit wire and deal with that later. Can someone please find this o-ring part # on the fiche? I looked everywhere. My best guess is #26 under crankcase, but says 2 are required.

[Missile99]

....The bowed piece of pan gasket

[Missile99]

... Tear in the gasket, or so it seems.

[tkent02]

Not sure, but you and Spyug should compare notes.

[Missile99]

... Thanks for dealing with my stupidity.

[tkent02]

I don't see any stupidity, I see a good question about an area not many of us are familiar with. Good luck to you and when you find out what the problem is make sure to let us know.

[Missile99]

It seems like I have read everything he posted and it looks like the entire engine was checked. I'm hoping that cleaning the screen and putting a new gasket on will solve my problem. Spyug, if you're out there, I wish you luck in finding the culprit.

[Missile99]

Thanks tkent02. I will post what I find wrong. Then I promise to ride the snot out of it. I have to say, I get a good laugh when someone worries about a weird sound on these noisy machines and that's your reply !!!!

[spyug]

On my 83 550 there are 2 of those orings. There is the one you show and there is another where the oil pickup "snorkel" joins the crankcase. In the 83 you take off the screen and inside the snorkel is a bolt holding it to the underside of the crankcase. The o-ring joins th tube in the snorkel to the hole feeding the oil pump. I am replacing both of these o-rings.

Now in your situation, it might be that you have a defective sender unit as they do go bad I'm told. You can check it by taking it out of the hole it sits in and with the wire attached and key on ground it to the case and shoot compressed air into the hol in the sender. If the light goes out then the sender is working and you may have a low /no pressure situation.

I'm not sure though about your engine is it a high pressure plain bearing engine like mine or is it the low pressure roller bearing engine. If its low pressure then it might just be that there is some gunk in the passage leading to the sender or the sender itself is plugged. You might shoot some compressed air down the sender hole to blow out any crap.

I haven't got mine sorted yet as I'm still waiting for my rings and gaskets but I'm hoping that changing the o-rings will sort it for me. I'll let you know.

Good luck with yours.
Spyug

[Missile99]

I think before the pan is buttoned up that I will try your suggestion of compressed air into the sending unit. According to the service manual, mine is a low pressure system.

The o-ring and what looks like a snorkel near the pickup screen still confuses me. Essentially when the pan is bolted up that passage is blocked, not only by the gasket but by the other end of the snorkel which is part of the pan casting. There are no cut-outs in this that would allow oil to be drawn through. Is this for vacuum? It almost looks like yours is the same. The oil is only drawn through the sump screen that I know of.

Good luck and by the way, who do you order your parts through? I have had trouble with Boulevard Suzuki and Suzuki Parts Pit Stop so far. The place near me within driving distance charges full retail. I am going to order with G&S Suzuki again. They were reasonable and got my parts to me quickly enough.

[Missile99]

Update - oil pressure good !!!!!!!!!!!

Although it never appeared that I had lost oil pressure, here's what I found:

The week before while taking the sending unit out I noticed there were scrapes along the wall of the case in 2 spots. It appeared that the brass washer was getting caught on the case at about the point where the unit plunger is fully depressed since there was an indent there. I don't know if this is truly possible because I wasn't looking right down over it to see clearances. If anyone knows whether or not these are machining marks, please chime in. I forgot to take pictures.

The other day before putting it all back together, I cleaned the sump screen of any particles, although it did not need it. Re-secured. I then installed the new pan gasket with o-ring, Suzuki oil filter, sending unit o-rings and a gauge from Renobruce. I took the brass washer and screw out of the sending unit.
The channel with o-ring that meets the pan gasket still confuses me. It must have something to do with the oil flow/pressure.

The pressure is about 2 psi at idle, around 12-13 at 6k rpm. Sweet.

[spyug]

Glad you got it sorted.

My problem was entirely of my own doing and if you think you have done some stupid things try putting the oil filter , which only goes in one way, the wrong way round essentially blocking off oil return to the sump.

The problem drove me bats but I did end up gaining an in depth education about the oil system.

I hope to never have to repeat that experience let me tell you.

Enjoy the ride.
Spyug

[Missile99]

Thanks Spyug. The mistake sucks but it happens. This is not repetitious work like an assembly line where if you miss a step or put something on wrong your brain stops you immediately. All good though, no repercussions regarding the bike. The only cost was a few gray hairs and pressure in your forehead, right?
The knowledge gain is always nice too.

I appreciate your wishes. Our riding season is becoming limited here. No snow of course but unbearable heat and downpours take enjoyment out of the ride. Mornings on my days off throughout the summer is when I'll go and maybe to work a couple times a week.

See ya.