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Can Oil stop light be triggered with bad lights?

RowWel

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I recently bought a 79 cb750 DOHC, guy converted it in to a cafe racer and put on these shitty after market tail lights and indicators. He blamed the oil stop lamp being on because they were cheap LED lights, uppon inspection of the wiring there are some relatively unreliable connections and the brake lights don't actually engage. More importantly though, I want to know if I was miss informed and that the light is only for oil related issues, it starts with it off but pretty much once I start riding and it warms up the light comes on.

Oil level is good
Is there anything I can check to see why the lights actually on? Any known issues with the oil pressure switch? Was he telling me the truth?

Just trying to make sure I don't kill the engine on the bike
 
Engine likely worn out. The light can flicker barely at idle in 90+ degree heat and be fine but anything over idle with light on is a dead engine. No, the rest of the system has nothing to do with the light, it is only for oil pressure. It trips on around 5-7 psi. The oil pressure switches are dependable as hell.
 
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Not sure if something like this would help! I agree with amc that idling with the light on would be bad.


 
A standard good running DOHC has more internal leaks (double the cams and attendant oil restrictions) than a SOHC and can flicker the light a little bit at idle due to it at over 90 degrees. So long as you never get any light at all past 2000 rpm ever you are fine. Oil weight may figure in too, a lot of guys run 20W-50 during the summer in them. A car weight like 30 can cause issue.
 
It's definitely consistently on, I thought it was strange him saying it was oil or brake light related... Thanks for the insight I just ran a compression test and 3cyls were around 110psi and the other was 90psi.
Worth a rebuild or should I find a donor motor in your opinion?
 
He was just poking fun..........nothing intentional or personal.

You might be better off with new engine, they are harder to get parts for than the SOHC and very expensive to build from the ground up. Low pressure often means the head has dead cam journals and you have to get a new head for that anyway.

FYI, OEM compression is 170 psi and anything under 100 is absolutely pretty much a dead cylinder. The valves never get set either and tend to burn the exhausts because of it.
 
He was just poking fun..........nothing intentional or personal.

You might be better off with new engine, they are harder to get parts for than the SOHC and very expensive to build from the ground up. Low pressure often means the head has dead cam journals and you have to get a new head for that anyway.

FYI, OEM compression is 170 psi and anything under 100 is absolutely pretty much a dead cylinder. The valves never get set either and tend to burn the exhausts because of it.

thank you
 
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