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2000 FLHR 95ci
18 Posts
Discussion Starter · #1 · (Edited)
I started a NEW THREAD, because the replies I was getting were of no help to me.
As for all you OIL FILTER experts; "Chrome don't get you home", but it sure looks pretty! I still use the K&N 171-C filter.
I run Castrol 20-50 in the summer, and Castrol 10-40 in the dead of winter. The bike runs great. It just SMOKES.
My primary problem is that my rear exhaust smokes when I let off on the throttle, after I have ridden for a while.

I own a 2000 TWIN-CAM, since 2007.
In 2011, I upgraded to S&S509 SOLID CAMS when it was time to replace the cam roller pads. I Love Solid Cams!
In 2018, my transmission slipped into neutral, as I was coming home from North Carolina. I had to have it towed home. I was unable to determine what was causing the failure, so I replaced the transmission with a 2003 Transmission from a wrecked bike.

Because I am a repairman-kinda-person, after I replaced the transmission, I eventually found that a small obsolete spring (only used in 1999 & 2000) in the shifter mandrel had froze up while it was retracted, during a gear change, causing my transmission shifting forks to become stuck in neutral.
I paid $800 for a transmission and new mounting cushions all because a small 25 cent spring had frozen up in a tiny shaft, in my shifting mandrel, inside my transmission.
The bike worked wonderfully since then.
In 2020, I removed the 88ci cylinders and had them professionally bored out to 95ci. Then I re-assembled it.
The bike ran great for 500 mile break-in, then a 500 mile trip to Outer Banks, then back home.
Next trip was 1000 miles to Travis County Texas (Waco/Killeen area), then back home. All was good.

This year has been rough.
1. My FLHR Road King started smoking out the rear exhaust when i let off on the throttle. (Compression is good, rings are good, plugs are good)
2. The FLYWHEEL POSITION SENSOR was going bad, making my bike run rough, until it died at the bottom of a steep hill 200 yards from my driveway.
I replaced that, and the bike ran great for local test rides. Could not believe it was running so well.

3. Then the rear OIL VENT TUBE (inside the air cleaner) cracked and oil covered my motor. (2nd time that has happened in the last 15 years)
No worries! New OIL VENT TUBES came from AMAZON, and I was riding great again, other than the smoking exhaust when I let off the throttle.

I checked down the oil filler cap looking to visually see OIL FLOW while motor was running, and became alarmed when I saw NO OIL FLOWING.
I initially thought oil was no longer circulating, and extra oil was being dumped into my air cleaner, and being burnt out the exhaust.
I was looking for possible causes for the oil to stop circulating.
Checked/Changed the oil filter with no difference. Not burning a "significant" amount of oil (since my last bike was a shovelhead).
Interestingly enough, while the motor was idling, I stuck my finger down the oil filler neck and felt a steady pulse of AIR from that oil line. Just NO OIL.
There was a light coating of dirty oil all over the bottom and sides of my 22 year old motor. I cleaned that up.
I thought the oil line across the top of my transmission was the main oil return line.
I pulled the oil return line from the top rear of my motor, to check for blockage. No blockage.
I feared that my motor was no longer circulating oil.

Today, I pulled my push rods, and opened my CAM COVER to check my OIL PUMP for any damage, blockage, or problems.
As I tried to find/follow the oil return path (from the oil pump to the oil reservoir (under the tranny), I became alarmed to find a wide open rough opening inside the engine case, where that "return" oil hose connects to the engine.
Further investigations led me to determine that this oil line is just an overflow/air VENT between the CAM COVER and the OIL FILLER tube.
I had mistakenly thought this was my main oil return line, and panicked.
Did I make this simple enough, so far?
If I recall correctly, (from back when I replaced the transmission) there are two hidden hoses, between the motor and the tranny, that allow oil circulation.
I can't find a diagram of the oil circulation path in my factory service manual, or online, which is why I joined this forum.

I am guessing that my OIL PUMP is probably functioning normally, and probably circulating the oil properly.
I will just put that all back together.
My next thoughts are that the UMBRELLA VENT in the rear cylinder has probably failed. I will investigate.
I just "freaked out" because I didn't see any oil return coming into the oil filler neck on my transmission.
Other than that; my bike runs great.
My bike just needs to stop smoking up the intersections at Red Lights, or when I pull into my driveway.

I appreciate your thoughts and suggestions. You asked me to keep you informed.
Hopefully, my long story eliminated a lot of your random guesses. I'll go put my bike back together, now.

21 LowRider S
44,705 Posts
Note that there are 2 halves of the oil pump. One to return oil to the tank from the crank case, and another to feed oil to the motor. The engine part of the oil flow will be on the next page of what is pictured in my quote. I've sold off my copy of the service manual so I can't take a pic of the next page anymore. But from memory it goes from oil pump to filter then to top end/rest of motor then drains to the crankcase to be picked up by the return side of the oil pump and back to the tank.

It could be that your feed side of the pump crapped out and that there is no oil in the crank case to be returned to the tank. That would explain why you are feeling pulses of air when cranking the motor.

Nope, JAGG isn't the only one. In fact, I think it would be pretty difficult and convoluted to to it otherwise....

Check the oil flow diagram in Fig 3-3....

Compare that to the mounting adaptor here:

I don't think it would matter much either way. Viscosity wouldn't change enough to make a difference.

2000 FLHR 95ci
18 Posts
Discussion Starter · #3 ·
Thanks for photo of the Oil feed path. Your manual is for a Soft-tail. I like figure 3-3 showing the oil flow thru the filter. I did not know that.
In figure 3-1, where the Soft-tail oil lines connect to the motor, I have short horizontal hoses that direct the oil to the oil reservoir beneath my transmission.
There is a small cover that hides these hoses, and I forgot about them being the main oil lines. That is why I thought the vent line (#4) was my main return line.
I also caught the play on your name.
When the bike is cold, I started it up, opened the air cleaner, and pulled the new oil vent hoses off the cylinder heads, just to see if I was getting any flow of oil into the air cleaner, but I was not getting anything draining from the rear cylinder.
I will have to go for a ride, and check that again when the motor is hot, and I get continuous smoke out my exhaust.
I am thinking that if I am getting oil flow from the rear cylinder into the air cleaner, while the motor is hot and running, I will open the rear head and check/repair/replace that "Umbrella vent".
Lately, the 100 degree heat has reduced my desire to go ride in the sunshine during daylight hours.
Cooler mountain weather (rain) is coming, soon.

Retired citizen
25,593 Posts
I would take the oil pump apart and inspect the gear rotors and plate for obvious scratches. Any scratches and the oil pump needs to be replaced.
Take heed of instructions for after market replacement oil pumps, they require the same pinion runout specs as the S&S gear drive cams.

2000 FLHR 95ci
18 Posts
Discussion Starter · #5 ·
I would take the oil pump apart and inspect the gear rotors and plate for obvious scratches. Any scratches and the oil pump needs to be replaced.
Take heed of instructions for after market replacement oil pumps, they require the same pinion runout specs as the S&S gear drive cams.
I change my oil regularly, and it seems that the rear cylinder is the only one smoking.
New Pistons and rings on the 95ci bore. minimal metal on the magneton my drain plug.
I'm not going to mess with my oil pump right now.
The bike is 22 years old. It probably has scratches on the rotors.
I've owned it for that past 15 years.
I probably didn't put something back together correctly when I put the jugs back on it. IDK.
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