Oil Pressure variations

[89 FXRS]

I noticed my oil pressure doing that too. At start up (cold) pressure would be 34 at idle. After riding for a while when oil is hot the pressure would drop down to between 5 and 10. But at 2000 to 2500 rpm's it will go back to 34. It freaked me out at first, but I have been reading a lot on the internet from other sites that this is normal?

From everything I've read and seen yes it is normal to show little to nothing at idle/ when warmed up 34psi is also normal at 2000rpm and above - the factory manual states that @2000rpm+ it should be 30-38psi.

Why would you go to all that trouble?We have used mechanical guages on the race cars for the last 25 yrs. and just route clear high pressure plastic hose from the sending unit to where we want to mount the guage.

I wanted to eliminate the sending unit so I could know if the problem was the gauge or the sending unit, it wasn't much trouble at all, just replaced the sending unit with a piece of tapered threaded pipe and did basically what you did.

 

[Baldeagle1]

Tx all!
I checked with my dealer and indeed the oil pressure xmitter is at fault, so I guess I'll have it replaced.
René

 

[horizonchaser]

Welcome to the forum. I have never seen warm oil pressure on my '07 as high as 50 psi. Mine stays between 34-40 above 2,000 rpm, and drops to nearly 0 at idle, (hot) which many others say theirs does. As soon as I get up to operating rpm again, the pressure comes back.

Oh man, I'm glad you said that others say their pressure drops to zero at idle because just the other day I was stopped at Light and looked down at the oil pressure gauge and it read zero! I thought "What the heck? Do I need oil? I better pull over before I seize the engine", but then I noticed that as I drove away the pressure rose. When I got home and checked the oil level it was fine.

 

[BUBBIE]

Oh man, I'm glad you said that others say their pressure drops to zero at idle because just the other day I was stopped at Light and looked down at the oil pressure gauge and it read zero! I thought "What the heck? Do I need oil? I better pull over before I seize the engine", but then I noticed that as I drove away the pressure rose. When I got home and checked the oil level it was fine.

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Most, notice i say MOST TC motors will Still pump oil at an idle EVEN IF it is not showing pressure on the gauge... IF the IDIOT Light stayed off it still has about 5/7 lbs and That is actually a lot of oil pressure...

IF the Idiot light comes ON at idle You may have your IDLE too Low, Low oil in tank or a pump PROBLEM..
I have noticed IT doesn't take Much in Slow Idle to lower oil pressure when motor is warm or HOT....

This is where/when I like using a Good Fully synthetic engine oil... It gets Lubed...

signed....BUBBIE

 

[84FXRS]

Take a look at this place, tech tips tells you where your pressure should be ,
an if you are running low pressure, a check valve kit to correct it

Harley-Davidson oil pressure problems solved without replacing the oil pump

 

[horizonchaser]

**************************************************

Most, notice i say MOST TC motors will Still pump oil at an idle EVEN IF it is not showing pressure on the gauge... IF the IDIOT Light stayed off it still has about 5/7 lbs and That is actually a lot of oil pressure...

IF the Idiot light comes ON at idle You may have your IDLE too Low, Low oil in tank or a pump PROBLEM..
I have noticed IT doesn't take Much in Slow Idle to lower oil pressure when motor is warm or HOT....

This is where/when I like using a Good Fully synthetic engine oil... It gets Lubed...

signed....BUBBIE

Thanks for that Bubbie. Makes me feel better knowing that I do use a good synthetic oil ( Mobil 1 )

 

[geezerglide57]

Hi There,
My bike, a 2003 Ultra Classic, suffers fom oil pressure variations.
While riding at say 2000 - 3000 rpm the pressure can vary between say 26 to over 50 psi.
So, one moment it low, and the next moment, e.g. after a short stop for a traffic light it can be up in the high 50 range.
The oil level is correct.
Can this hurt the engine and has anyone experienced this too?

Many thanks,
René

How many miles are on your bike?...I have seen this happen when the cam chain tensioners are going bad...If you are approaching the 30 to 40,000 mile mark and haven't had them replaced or checked you might want to get it checked out

 

[IBA Harley]

Yeah, I can remember the first time I looked down and saw the guage reading "0". That put a scare in me!!