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Discussion Starter #1
maybe im beating a dead horse here, but wanted some input on my possible issue.

i bought this bike from a neighbor and its been sitting 2-6 years. dont ask why those years vary so much, its just a mystery.
the bike wouldnt read oil pressure for 5-10 minutes of the bike running. 0 at gauge and dummy light on
it would then seemingly act normal. read low at idle and about 30psi (center of gauge) at cruising speed.

i went on a longer ride a while back,parked for a few and when i started it back up i never got the oil pressure back.
it would read 0 at idle and 3-5psi (if that) when revved.

i wasnt sure if the pump was actually failing or if it was a gauge issue or what was going on so i said **** it and rode home. keeping an ear for engine noise.
it was about a 30 mile ride home. never made any sort of wacky engine noise.

when i talk to my buddies about my issue theyre all tell me that happens with those year twin cam motors, their oil pumps and or cams go and there an upgrade kit for sale and its like 800$ for the parts.

i dont like throwing money at problems.

how do i properly diagnose a loss of oil pressure in my system.
i assume part of that will be checking for blocked ports.

do people fix this issue without the upgrade kit (s&s i think)
 

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After 2-6 years of sitting getting gummed up, I would clean out the oil lines going to the gauge first then a new gauge before spending $800 on a upgrade kit. Although I would start saving for the eventual and imminent upgrade.
 

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Buy a factory service manual.
If in fact the oil pressure readings are as indicated in your post then I would do these things first.Open up the cam chest.Remove the cam plate and check, the oil pump, the scavenge
o-ring where the pump spigot goes into the case, remove the oil pressure relief plunger and spring to see if it is sticking and to clean and polish the plunger.
I suspect the oil relief plunger may be sticking.
 

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You didn't ride 30 miles without oil pressure. Installing guage like TT suggest will give you what you're looking for. Start saving your lunch money for the cam tensioner upgrade, keep pushing those spring tensioners and you'll liable to get that wacky engine noise you were looking for.
 

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well put jammer,,,, harleys arent really easy to work on even moreso with troubleshooting issues...

a good working knowlwdge of machinery is a good primer for maintaining harleys,, although there is alot of room for interpretating between the manuals, and what actually occurs...

i have on several occasions, contacted corporate with "errors' in the manuals,, the response was,,, "the manuals are for use by experienced techs at a Harley dealership..
 

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Discussion Starter #8
I have the money for the upgrade kit. I just want to properly diagnose the issue first.

the oil in the bike looked new when i changed it. Assuming its not all gummed up in there.

Wont the push rods fall in the cam area if i pull the chest plate and cams?

whats a service oil pressure gauge, just an oil pressure gauge? And i should install that where my dummy light connects? Can you elaborate a little please.

the bike had normal oil pressure for its first handful of rides, minus the 5-10 minutes of not reading anything. That mist be a hint towards something.
 

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You got it. Unscrew the oil pressure sending unit, screw in fitting for manual oil pressure gauge. Totally agree, get the pressure indicator Issue behind you. Then address cam chain tensioners. Factory service manual will pay for itself many times over.
 

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its just a gauge with adapters to test for oil pressure on most vehicles,, it doesnt stay on the bike,,,
if you choose to leave a gauge on the bike,, a mechanical gauge is more responsive to pressure changes,,, electrical gauges have a lag time...

um,,, no the push rods dont fall into the cam chest,,, they are remeved first,, from the top side,, remove top rocker boxes and rocker stands,, then pushrods..
 

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Discussion Starter #11
Its my understanding that the oil pressure gauge and dummy light are separate indicators and if theyre both telling you theres no pressure, then theres no pressure.
Can anybody point me where to look for a manual. Didnt see anything on ebay
 

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most harleys do not have both... at least from the factory...
i have plumbed in a line for a mechanical oil pressure gauge,, by using a fitting between the engine and sender for the light
 

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The MOCO sells oil pressure gauge kits, complete. My part # was 75133-99, yours might be different. Comes with brackets, plumbing, and all fittings and adapters. Some of the components are cheesy and you might get more than a year out of the gauge itself, but don't be too disappointed if it dies an early death. Just use that as an opportunity to do better. As usual, the aftermarket has many solutions. After the original gauge died, it was replaced with an Accel gauge, still good over 15 years later. And the plastic line from the Tee to the gauge became braided stainless pretty quick too.

Generally, that's more information than you really need. As long as the light doesn't come on when the engine is running, your pressure is good. On one really hot August day many years ago, my gauge went all the way down to zero, but the light didn't come on. Happened only that one time. Normally it will get down to 10-12 psig. But it's all relative. I don't know if that is real and correct, but I do know the range that is normal operation.

Nothing lasts forever. Before spending that big pile of money, replace the oil pressure switch. That's what Harley calls it. It's not a real sending unit. Just on or off. The kit mounts the Tee between the motor and the switch and sends pressurized oil up to the gauge. That's why the gauge can show a range of pressure.

Also, be sure you don't have an Evo filter screwed to your TC by mistake. They don't have an anti-drain back valve and will give a long oil light at startup (but not 5 to 10 minutes).
 

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Just looking at the filter, you can't tell the difference. There's no flashing light or buzzer that tells you it's the wrong filter. Just a possibility. Not saying it is a problem.
 

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What is an evo filter to my tc?
What rootintootin is saying is oil filters for EVO motors restrict too much for Twin Cam Motors.
Your dealer will order a service manual for you
Just because your guage indicated no pressure doesn't mean there wasn't any. I doubt the motor would have run 10 minutes without oil pressure.
 

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i believe,, but may be wrong,, the evo filter has less restriction since the evo filters to 20 microns and the TC to 10 microns... and the anti drain back valve..

you could just pick up a good auromotive gauge and fabricate a mount for it... i dont trust the readings of harleys purdy gauge kits...
 

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Evo oil goes straight from the pump to the engine unfiltered. After collecting in the crankcases, it then goes through the filter on the way back to the oil tank. TC oil is pumped first to the filter before it returns to the cam plate to be distributed throughout the motor. That valve in the filter keeps the oil from draining back out of the filter whenever it sits not running for an hour, a day, a week, a month, a year, etc. This prevents that dry start up. I'm not saying its 5 to 10 minutes, But I have seen as much as 30 seconds before the oil light goes out. Just thinking that in a severe enough case, you could lose the prime in the oil pump making it last longer. Or that could be total BS.
 

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Further research shows that Electra Glides use an actual sender different from the switch I was talking about. Probably because it already has it's own gauge. I'm sure the Moco used a better quality of gauge for the ones that come as standard equipment than the things they put in their add on kits.

I would still start there. 74438-99A. $30-35. Or maybe after swapping out that filter for a known good one.

Ok, I'm done. Nothing else to say. I'll go sit in my corner and shut up.
 
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