I bought my 1984 GL1200I last December. 43K on frame with a 72K engine. She spent a lot of downtime as I fixed her up for use. Last July she popped her stator and became unuseable. I tore her down and replaced the stator and got her running again about September 22. I filled her wilth Motul 10W40 and Honda Coolant and ran her 30 minutes on the centerstand. Then I started a ride to cleanout the old junk. etc.
After a 10 minute ride on the freeway the OIL light came on. I shut her down and let the engine cool and limped home. I was shocked because I had never gotten this indication before.
I pulled the OIL switch and cranked her to clear the oil passage. After 5 seconds the oil came out in pulses. I bought and hooked up an oil pressure gauge.
First test: cold. She gave 25 psi at 1,000 rpm. No increase at 2,000+ rpm.
First test: hot. She gave about 12 psi at 1,000 rpm. No increase at 2000+ rpm, except 2 brief jumps to 25 psi at 2,000 rpm before dropping back to 12 psi.
I theorized that the oil pump relief valve was sticking, because she sat dry for 2 months in our 95+ temps. I added 8 ounces of Seafoam and ran her from cold to hot a few times.
Second test:cold. She gave 25 psi at 1,000 rpm. Instant increase to 35 psi at 2000+rpm. There is a hard limit at 35 psi as rpms are increased further.
Second test:hot. She gave 12 psi at 1,000 rpm. Instant increase to 25 psi at 2,000+ rpm.There is a hard limit at 25 psi as rpms are increased further.
Bottom lines: the oil pump relief valve got stuck from sitting 2 months dry in heat. The Seafoam freed the valve so it worked better. I am not comfortable with the 25 psi hot. I believe the pump relief spring has softened/shortened over the past 20 years and opens too soon, limiting pressure at 25 psi. My plan is to get a new valve, spring, etc and install them. Should I replace the rotors at the same time? BikeBandit only shows the outer rotor for $35.