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[longlast]

I had an oil change back in the early part of June. I can't recall the motor oil weight, but do recall the shop saying 50/75w in gear box and primary. I would have thought the shop would put the correct weight oil in.
My concern is my oil pressure drops way low on hot idle (at least I think it dose) On one auction,..hot day, hot motor idling the oil light came on. I'm thinking this low pressure the heads may not be getting any oil when I'm sitting  at idle.

What dose your gauge read at what "W" oil? (on idle) Can  I change W to bring up idle pressure?

Two pics, first is idle on start up of hot motor that has sat for 45min.   Sorry the pics are not better quality     

[longlast]

This is on hot idle

[J-Carr]

Mine drops to near zero when sitting at a light at idle in temps above 85(F).  The dealer assured me its normal.  I know a bunch of other HDs that do exactly the same thing so I'm guessing its normal.  BTW, mine's been that way for 7 years now.  So I guess it was normal.   

If you hit the gas and it doesn't come back up, or your riding down the road and it drops to that, then pull over and see what the problem is.

Oh, sorry... I run 20w/50 HD Syn 3.  Year round.

[grc]

I had an oil change back in the early part of June. I can't recall the motor oil weight, but do recall the shop saying 50/75w in gear box and primary. I would have thought the shop would put the correct weight oil in.
My concern is my oil pressure drops way low on hot idle (at least I think it dose) On one auction,..hot day, hot motor idling the oil light came on. I'm thinking this low pressure the heads may not be getting any oil when I'm sitting  at idle.

What dose your gauge read at what "W" oil? (on idle) Can  I change W to bring up idle pressure?

Two pics, first is idle on start up of hot motor that has sat for 45min.   Sorry the pics are not better quality     

At hot idle the oil pressure will usually drop to somewhere in the 8 to 12 psi range, depending on how hot the oil actually gets, and some bikes will show even less on the gauge. As best I can tell from your second photo, it looks like it's reading about 6 psi in that shot. I wouldn't be too concerned if the gauge dropped to 5 psi when truly hot, but if the oil pressure idiot light came on then I'd say you have a problem.  Those things don't usually come on until oil pressure is nearly zero.  Twin Cam engines do not normally idle at zero oil pressure, no matter what a dealer may tell people.  Shovel's and Evo's yes, Twin Cam's no.  The gauges may not be real accurate, but as I said, if the oil light comes on that isn't right.  What does the gauge show for oil pressure when you're running at 2500 rpm on the road? 

Btw, the motor oil specs are in the owner's manual.  Harley recommends 20w50 motor oil for most conditions.  The trans should normally have 75w90 unless you're planning a trip to the north pole. 

Did you see this same behavior prior to the oil change?

Jerry

[TNCarters]

With Mobil 1 20w-50 I'll run between 10-12psi at idle when hot.  I've seen it lower than this when stuck in traffic on very hot days.  This can be improved with a different weight oil.  Syn3 is probably one of the lighter weight oils when hot.  Our summers in middle Tennessee tend to be very hot, many times above 90 F.  I've been trying a 15w-60 for a couple of months which helps hold the pressure a little higher.  I've read its generally not recommended to let a bike sit and idle for extended periods of time at low pressure but I would not think normal use idle would be a problem.

[Rooster]

Out of pure guilt I have blipped the throttle once or twice while sitting just a feel good to see it jump up some.

[longlast]

At hot idle the oil pressure will usually drop to somewhere in the 8 to 12 psi range, depending on how hot the oil actually gets, and some bikes will show even less on the gauge. As best I can tell from your second photo, it looks like it's reading about 6 psi in that shot. I wouldn't be too concerned if the gauge dropped to 5 psi when truly hot, but if the oil pressure idiot light came on then I'd say you have a problem.  Those things don't usually come on until oil pressure is nearly zero.  Twin Cam engines do not normally idle at zero oil pressure, no matter what a dealer may tell people.  Shovel's and Evo's yes, Twin Cam's no.  The gauges may not be real accurate, but as I said, if the oil light comes on that isn't right.  What does the gauge show for oil pressure when you're running at 2500 rpm on the road? 

Btw, the motor oil specs are in the owner's manual.  Harley recommends 20w50 motor oil for most conditions.  The trans should normally have 75w90 unless you're planning a trip to the north pole. 

Did you see this same behavior prior to the oil change?

Jerry

From what your self and others are saying it's pretty much normal. Prior the change it was down around the 5psi mark. It was after that it started dropping lower. like I said I can't recall what "W" they put in. The idiot light has only come on the once very hot day slow- slow moving city traffic
Pressure  pops right back up with the slightest rpm increase.
Perhaps I should change it again? I'm thinking what's in there isn't handle it.
The longer it idles the lower it gets. After I had taken the second pic it was nearing the zero pressure point.  I don't know if it would drop to zero because at no time do I want no oil flow so when it starts dropping below 5psi I tweak the throttle       

[Chains]

Mine runs around 12 to 15 at idle when hot. My 06 was lower around 8 or less. Running Mobile one 20/50

Now my Evo motors got down in the no pressure zone when hot.

[grc]

From what your self and others are saying it's pretty much normal. Prior the change it was down around the 5psi mark. It was after that it started dropping lower. like I said I can't recall what "W" they put in. The idiot light has only come on the once very hot day slow- slow moving city traffic
Pressure  pops right back up with the slightest rpm increase.
Perhaps I should change it again? I'm thinking what's in there isn't handle it.
The longer it idles the lower it gets. After I had taken the second pic it was nearing the zero pressure point.  I don't know if it would drop to zero because at no time do I want no oil flow so when it starts dropping below 5psi I tweak the throttle       

The idiot light is supposed to come on when pressure is less than 3 psi btw. 

You might want to verify your gauge is accurate by installing a calibrated mechanics gauge T'ed into the fitting for the oil pressure sending unit.  Most Harley shops should have the simple setup required.  Before assuming anything, I like to know what the real readings are versus the "close enough for government work" cheap gauges Harley installs.  But let's say your gauge is accurate, and when you're running down the road at 2000 rpm and full operating temperature the oil pressure is at least 30 psi (30-38 psi is the spec, most run right around 32 psi at 2000 rpm).  If the oil pressure meets the specifications at cruise speeds, but is too low at idle, it could indicate a worn oil pump, or the pressure relief valve may not be sealing completely at idle.  That has been a common issue due to poor machining of the cam plates and the shuttle valve over the years.  The aftermarket has offered many "cures", or some people have just removed the valves and cleaned them up with abrasives along with the seat in the cam plate.  At hot idle the relief valve should not be bypassing anything, but many do.

Anyhow, it wouldn't hurt to change the oil first and see if that's the real problem.  One more reason I like to do fluid changes myself; you can't always tell what the shop dumped in versus what you wanted.

Jerry

[ChuckB]

I was wondering.. when you say "idling" , what RPM are you talking about?

[phato1]

My 11.5 usually shows @15  PSI on the gauge at a hot idle, and easily double that going down the road. I use Mobil 1 20/50.

Have you checked the level since the change? Perhaps it is a low oil level resulting in the oil light coming on and not the idle pressure?

[grc]

The oil light is only affected by oil pressure, not fluid level.  Harley doesn't believe in low oil lights or low coolant lights (too expensive, and I'm not sure they'd know how to set them up anyway).

Jerry

[phato1]

The oil light is only affected by oil pressure, not fluid level.  Harley doesn't believe in low oil lights or low coolant lights (too expensive, and I'm not sure they'd know how to set them up anyway).

Jerry

Ain't that the truth 

[longlast]

I was wondering.. when you say "idling" , what RPM are you talking about?

RPM. is 900 if I throttle it just under 1000 RPM it lifts over 5psi

[CVODON]

Why didn't you first call and find out what they used when they changed it last time? Have you "tee'd" into the line and verified the gauge is actually working? Sounds like it is if low pressure light came on. I think you are wasting you time to just change oil hoping it will get better, it is not going to mysteriously get better unless you have somesort of blockage in system that just goes away? Doesn't normally work like that.