1981 R100RS

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jestack1
Posts: 3
Joined: Sat May 22, 2021 8:42 pm

1981 R100RS

Post by jestack1 »

Hi All,

I noticed some lite smoking at the front of the engine (down by exhaust pipes) as I was warming up for my ride this morning....70 degrees.
I have not noticed this before and the red oil light was on briefly then turned off and did not come back on...oil is fresh and at proper levels.

I will keep my eye on this situation, but is this anything to be concerned about?

Thank you in advance for your comments.

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schrader7032
Posts: 7682
Joined: Fri Oct 27, 2006 3:00 am
Location: San Antonio, TX

Re: 1981 R100RS

Post by schrader7032 »

Welcome to the forum! Certainly keep an eye on things...maybe look around when things have cooled down to see if you find any fluids in an area where they are not supposed to be.

You say red light for oil. Not totally sure on the '81 but on my '78 /7, the red light is for the generator...the oil pressure light is yellow.
Kurt in S.A.
'78 R100/7 '69 R69S '52 R25/2

jestack1
Posts: 3
Joined: Sat May 22, 2021 8:42 pm

Re: 1981 R100RS

Post by jestack1 »

Thank you Kurt, appreciate your taking the time to respond. I went back and looked again and while both lights are red, it may have been the battery charge (generator) light that came on and not the oil pressure warning. I will have a look at that too.

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srankin
Posts: 271
Joined: Fri Jul 14, 2017 8:45 pm
Location: Spencerport, NY USA

Re: 1981 R100RS

Post by srankin »

The battery charge light will come on while the key is on and the bike is running along with the oil pressure light. When the bike is running, the oil pressure light should go out immediately after start up. The charging light will stay on at idle speed until you reach a higher RPM than idle, about 1500 to 2K RPM.

I think the charge light is red and the oil light is yellow. St.
Owner of a 84, R80RT and 78, R100RS

OldCrow
Posts: 6
Joined: Sun May 02, 2021 6:52 pm

Re: 1981 R100RS

Post by OldCrow »

Yellow Oil pressure light? Just reminds us how old these bikes are when the most critical system warning is Yellow and not RED.
Not on my "modern :D " 1981 R100RT, both oil and alternator are RED. And my oil light goes out while cranking and the Alternator is out above about 1000-1200rpm. Unless it's a faulty oil pressure sender or wiring issues the light should never come on once the motor running, just cranking should extinguish the light once pressure builds.
OC

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srankin
Posts: 271
Joined: Fri Jul 14, 2017 8:45 pm
Location: Spencerport, NY USA

Re: 1981 R100RS

Post by srankin »

Yes, the oil light should go out with just a few seconds of cranking. I got my message a bit mixed up. It is not a good idea to start the bikes if the oil light doesn't go out when cranking or very shortly after after the bike starts. St.
Owner of a 84, R80RT and 78, R100RS

OldCrow
Posts: 6
Joined: Sun May 02, 2021 6:52 pm

Re: 1981 R100RS

Post by OldCrow »

Just a data point.
I changed the oil today with Valvoline 20W50 VR1(high Zinc content) and new filter, 3qts. Did a test to see how long from a full drain, let sit for an hour draining, refill and cranking until the oil pressure light goes out. I pulled the plugs and grounded them to the heads with jumpers. With a full battery and counting one thousand one, one thousand two etc. I saw the light extinguish at about 16 seconds. The oil cooler had drained also but should not have been open since the engine was cold during the test.
OC

jestack1
Posts: 3
Joined: Sat May 22, 2021 8:42 pm

Re: 1981 R100RS

Post by jestack1 »

Many thanks to all who took the time to reply...I appreciate the benefit of your experiences!

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