Oil Pressure?

[mmaddix]

Anyone know what the oil pressure is supposed to be on a pressure gauge hooked up where the bolt is under the timing cover?

[mmaddix]

The reason why I'm asking is because when I first start up the gauge reads like 50-60psi but as it warms up while im riding and i stop at a light it goes almost to 0psi. My oil light doesn't come on but i am trying to find out if maybe the gauge reads low when it gets hot or maybe the oil pressure is actually getting low. I am probably going to change my oil and check the pump and the o ring for the pump while I'm at it.

[TopCatGr58]

IIRC, stock pressure values are supposed to be around 60 or so PSI.

Tod/Trbig posted a while back about a similar problem with his clutch, and a loss of lubrication. Turned out the cause was in inadvertant swapping of the large thrust washer that is behind the clutch basket with the one that is INSIDE the clutch basket between the clutch boss and the inner pressure plate. The one inside the basket is the same thickness, but is larger in diameter, and when installed on the clutch shaft behind the basket, it blocks the access of the oil to that bearing. It may not be your problem as to why the clutch throwout plate was making contact with the outer star plate??

T.C.

[mmaddix]

I tried just changing the oil because I didnt have time to drop the whole pan. I Used Valvoline 20w-50 motorcycle oil. When I changed the oil just about the same thing happens. when the bike warms up the gauge reads about 10 psi. So I turned the bike off and took the gauge off. I put a brand new pressure gauge i had laying around on just to see what it would read and it read the same as the first gauge. I dont see why it would make a difference because pressure is pressure but the new gauge i tried was originally for air pressure i think. I am about to bypass the oil cooler just to make sure there isn't a problem with that. If not im going to be changing the oil pump. yay.

[crazy steve]

According to the FSM, oil pressure at 'cruising' speed (whatever that is) should be about 40 PSI. I'm sure it goes down at lower speeds.

The warning light comes on if pressure goes below 4 PSI, so there's obviously a pretty wide allowable 'range'. If the light isn't coming on, I wouldn't worry.

Oil pressure gauges on bikes rarely give useful info... A oil temp gauge would be better...

[mmaddix]

Thanks for the info. I probably should of waited till I got more information but I didn't. By time I got your reply I just got the oil pump out. I looked it over and everything looked good. It seamed to be working fine and since I read your reply I decided to just put it back together after cleaning out the oil pan of course.

I'm glad I took it apart anyways it gave me something to do on my bike that I got done before bed and I was able to clean out the oil pan. This is how it loved when I pulled it off.


Also I while I had the pan off I saw the cam chain towards the front of the engine so I used a screw driver to push on it just to see how tight it was. It had allot of slack. Is it normal for that part of the chain to have allot of slack?

[WMarshy]

...
Also I while I had the pan off I saw the cam chain towards the front of the engine so I used a screw driver to push on it just to see how tight it was. It had allot of slack. Is it normal for that part of the chain to have allot of slack?

There really shouldn't be much slack at all. Are you using the original cam chain tensioner? You should adjust it at a minimum if there is slack or ditch it for a ratcheting automatic adjuster (ACCT). Make sure you read how to make the swap before hand. Heck I recommend you read about what can go wrong with the original ones before you make an adjustment, that alone will make you want to switch to the ACCT.

[crazy steve]

The chain he's seeing is the Hy-vo chain between the crankshaft and the transmission. Yes, play in this chain is 'normal' (there is no tensioner on it). This is the chain that's responsible for the 'driveline snatch' that the magazine reviewers complained about when the bikes were new....

[mmaddix]

Oh. That makes more sense because i did the cam chain tentioner mod where you tap the tentioner and use a bolt and nut and out seamed good.

Thanks for the help everybody.

[edwardruth]

I know this is really old but no one mentioned it. When oil heats up, it thins out and makes less pressure. You were right, pressure is pressure, but for things that expand and contract with heat, pressure changes. Car engines do it too.

[mack]

Yep

I asked the same question a few months back and got a wide vaiety of responses. I know a guy who builds racing motors and he knows the XS very well. He said between 40-60 Lbs. Apparently the XS motor is widely used in a variety of racing applications because of it's bullet proof design.

[motoman]

I know this is really old but no one mentioned it. When oil heats up, it thins out and makes less pressure. You were right, pressure is pressure, but for things that expand and contract with heat, pressure changes. Car engines do it too.

It's a gear pump, so pressure varies with rpm. FYI, it only takes 7psi to 'hold' and maintain a rod/crank bearing.

[BA80]

Also, where the supply tube connects to the head isn't a real good spot to check the pressure. Take the oil pressure sender out of the top of the case and connect your guage there and see if it makes a difference.

[edwardruth]

It's a gear pump, so pressure varies with rpm. FYI, it only takes 7psi to 'hold' and maintain a rod/crank bearing.

Agreed, that too, but not just rpm. Maybe it's easier to notice with high volume pumps on V8s, but my Chevy 350 (400HP) which is also a gear drivin pump but when it's cold and at idle it runs about 80psi, when it's warmed up at idle it runs about 20-40psi and that's with no choke and no fast idle. 600rpm-ish. I imagine in some really cold temps my pressure would be considerably higher at initial startup because of how extra thick the oil would be. It's half the reason batteries die quick in the extreme cold when starting, the other half is however the cold affects the battery itself. It's always harder when it's cold for the crankshaft to rotate its bulkyness and splash through the cold, thick oil which in turn lubricates the pistons and cylinder walls.

Someone said it was 4psi for the bike. But, I like 7 better. lol

I was on this thread looking for some info about what kind of gauge to use. After reading about Bonz Franken bike, I'm thinking it was also in the old fairing. I was also told it had a factory fairing and it's also a 79F. Weird maybe? Does not look like an 80 though. I put an 81 Yamaha/Vetter fairing on it since I got it. Same original color too. I wanted the Pacifico but couldn't find one. Wanna trade anyone? lol My problem is I can't seem to find a gauge that would work well for the bike as in size and being able to mount it nicely. Standard aftermarket car gauges are too big. Any suggestions?

[BA80]

I have a Pacifico out in the shed. Not sure of the condition, I'll have to get a look at it.

Those things are huge and expensive to ship though.