Author Topic: Oil pressure drop on acceleration  (Read 619 times)

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Offline Prostock

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Oil pressure drop on acceleration
« on: January 08, 2018, 09:36:39 AM »
Bike is a 2010 FLHX with a S@S 124 HC 640. Rebuilt,  cp pistons, ward heads ect.  Will NOT do it on the dyno.  Only does it on the road.  Hit the throttle and oil pressure goes to 10lb's +/- and comes back up within a second or two.  Doesn't matter what gear. Gauge and sensor replaced.  Oil level set 2 bars down. Bike runs great, no additional lifter clatter.   Any thought's.  Thx

Offline Ohio HD

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Re: Oil pressure drop on acceleration
« Reply #1 on: January 08, 2018, 09:39:28 AM »
Just a guess, on the road the oil level might be going to the rear of the pan. Is it under acceleration, or anytime on the road?
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Offline Thermodyne

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Re: Oil pressure drop on acceleration
« Reply #2 on: January 08, 2018, 09:49:24 AM »
Put a service gauge on it and make sure its not an electrical issue.  You can just buy one of those cheap ad-on mechanical gauges if you don't have a service gauge set with a long hose.  I think you'll end up finding a break in a wire or a loose connector somewhere.   

Any sort of pick up issue between the pump and pan should be evident as long an the scooter is under acceleration load. 

If the issue shows on the mechanical gauge, you might also want to double check the trans to motor interface.  Make sure that the bolts are tight and that none of the bosses are cracked.

Offline Coyote

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Re: Oil pressure drop on acceleration
« Reply #3 on: January 08, 2018, 09:50:13 AM »
Just a guess, on the road the oil level might be going to the rear of the pan. Is it under acceleration, or anytime on the road?

Never seen it on a stock pan but I sure have on a +1.5
I feel the need... for twisties with speed.

Offline Ohio HD

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Re: Oil pressure drop on acceleration
« Reply #4 on: January 08, 2018, 09:52:16 AM »
Just a guess, on the road the oil level might be going to the rear of the pan. Is it under acceleration, or anytime on the road?

Never seen it on a stock pan but I sure have on a +1.5

I've not seen it either, but just wonder if something (I don't know what) is trapped in the pan or restricting the flow to the pump. 
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Offline 02FYRFTR

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Re: Oil pressure drop on acceleration
« Reply #5 on: January 08, 2018, 10:35:33 AM »
Did you remove the  oil pan and replace the gasket, you may have been given the wrong gasket as the gaskets for EVO and Twin Cam are very similar.

Offline Prostock

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Re: Oil pressure drop on acceleration
« Reply #6 on: January 08, 2018, 10:47:30 AM »
OMG 02.  Just checked the part number on gasket and pa pow.  93-98.  Can't believe I missed that. Thank You!

Offline sfmichael

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Re: Oil pressure drop on acceleration
« Reply #7 on: January 08, 2018, 12:11:02 PM »
Did you remove the  oil pan and replace the gasket, you may have been given the wrong gasket as the gaskets for EVO and Twin Cam are very similar.

nice catch  :up: :up:
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Offline Rockout Rocker Products

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Re: Oil pressure drop on acceleration
« Reply #8 on: January 08, 2018, 12:26:15 PM »
Awesome  :up:
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Offline HroadhogD1

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Re: Oil pressure drop on acceleration
« Reply #9 on: January 08, 2018, 12:41:05 PM »


       Wow, amazing.

Offline motorhogman

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Re: Oil pressure drop on acceleration
« Reply #10 on: January 08, 2018, 01:20:54 PM »
OK for the inept at understanding this, How does the gasket cause this ?
where's the points and condenser ?
Tom / aka motor

Offline FSG

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Re: Oil pressure drop on acceleration
« Reply #11 on: January 08, 2018, 02:27:19 PM »
sucking air where the gasket is missing


Offline motorhogman

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Re: Oil pressure drop on acceleration
« Reply #12 on: January 08, 2018, 02:55:32 PM »
sucking air where the gasket is missing



TY  FSG 
where's the points and condenser ?
Tom / aka motor

Offline FSG

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Re: Oil pressure drop on acceleration
« Reply #13 on: January 08, 2018, 02:56:06 PM »

Offline Deye76

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Re: Oil pressure drop on acceleration
« Reply #14 on: January 09, 2018, 04:44:47 AM »
It's the gasket, happened to me courtesy of a indy I used to go to.  :angry:
East Tenn.
2014 CVO RK, 2015 RGS, 1992 FXRP

Offline harleytuner

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Re: Oil pressure drop on acceleration
« Reply #15 on: January 09, 2018, 05:59:54 AM »
Did you remove the  oil pan and replace the gasket, you may have been given the wrong gasket as the gaskets for EVO and Twin Cam are very similar.

Wow that was an awesome catch.  Nice job.
Enjoying the hell out of my "hotted" up twincam

Offline No Cents

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Re: Oil pressure drop on acceleration
« Reply #16 on: January 09, 2018, 09:25:14 AM »
    :agree:
great catch 02!  :up:
08 FLHX 124", wfolarry 110 heads, CR630i cams, Burns pipe, 158/152 sae

Offline OldBogie

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Re: Oil pressure drop on acceleration
« Reply #17 on: January 09, 2018, 10:54:30 AM »
Bike is a 2010 FLHX with a S@S 124 HC 640. Rebuilt,  cp pistons, ward heads ect.  Will NOT do it on the dyno.  Only does it on the road.  Hit the throttle and oil pressure goes to 10lb's +/- and comes back up within a second or two.  Doesn't matter what gear. Gauge and sensor replaced.  Oil level set 2 bars down. Bike runs great, no additional lifter clatter.   Any thought's.  Thx

It's a feed problem whether the oil in the tank runs away from the pick up, or the oil level is too low in the tank exposing the pickup or allowing a vortex to form that sucks air instead of oil, or the lines are too small to feed the pump when forces of acceleration are applied. It obviously is something with the vehicle dynamic that is causing the problem.

Bogie

Offline Breeze

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Re: Oil pressure drop on acceleration
« Reply #18 on: January 09, 2018, 12:34:57 PM »
'02; Great catch!

FSG; How do you ALWAYS have the correct photo to edit and illustrate?  :scratch:
I think I'll just stay home today, it looks too peoplely out there.

Offline BVHOG

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Re: Oil pressure drop on acceleration
« Reply #19 on: January 09, 2018, 01:49:09 PM »
Did you remove the  oil pan and replace the gasket, you may have been given the wrong gasket as the gaskets for EVO and Twin Cam are very similar.
Nice catch!!! Just think of the problems this forum just saved the OP
If you don't have a sense of humor you probably have no sense at all.

Offline FSG

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Re: Oil pressure drop on acceleration
« Reply #20 on: January 09, 2018, 02:20:21 PM »
Quote
It obviously is something with the vehicle dynamic that is causing the problem.

 :scratch:

Offline Chippitt68

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Re: Oil pressure drop on acceleration
« Reply #21 on: January 09, 2018, 02:22:30 PM »
Any idea as to why it wasn’t doing it on the dyno?

Offline No Cents

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Re: Oil pressure drop on acceleration
« Reply #22 on: January 09, 2018, 03:01:32 PM »
Any idea as to why it wasn’t doing it on the dyno?

   it might of been doing it on the dyno  :nix:  ...but not as bad once the bike was ridden.
It was sucking in air anytime the oil level was below the gasket surface. It's possible that sitting up level on the dyno that it was getting enough oil to keep the oil pressure up. But once the bike was on the street with the oil sloshing around in the pan and under acceleration or decel the oil level moved and it had to be lower than the gasket level which allowed it to suck in more air with little oil going with it...hence the pressure drop.
08 FLHX 124", wfolarry 110 heads, CR630i cams, Burns pipe, 158/152 sae

Offline Chippitt68

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Re: Oil pressure drop on acceleration
« Reply #23 on: January 09, 2018, 03:10:36 PM »
Thanks :up:

Offline No Cents

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Re: Oil pressure drop on acceleration
« Reply #24 on: January 09, 2018, 04:00:58 PM »
   where Gary (FSG) pointed the red arrow at in the oil pan...it didn't have gasket material there to seal around the hole. Whatever the thickness of the gasket is...was leaving a gap around the hole for air to be sucked in.
08 FLHX 124", wfolarry 110 heads, CR630i cams, Burns pipe, 158/152 sae

Offline Deye76

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Re: Oil pressure drop on acceleration
« Reply #25 on: January 09, 2018, 04:02:18 PM »
I could watch the pressure gauge drop under acceleration, cruising on a flat surface gauge read good, also read good on the dyno. Correct gasket solved it.
East Tenn.
2014 CVO RK, 2015 RGS, 1992 FXRP