Oil pressure light

Approximately how long should the light stay on after a cold start?

Lately, my KZ750B-4 takes about five to six secs to extinguish. When already primed by a previous start, the light will go out within a sec.

I've owned this bike over 30 years and don't know if this is an anomaly or maybe it has always taken this long and I'm just now noticing it. I don't think it always took this long.

Some background.....noticed oil level was higher than the sight level glass. This, I think was caused by gas leaking from one carb whose float level valve was not closing properly. You would think that the overflow tube would have done its job, but the tube does go up way higher than the bowl to body line. All I can figure is that gas seeped up from needle jet and flooded down into manifold to cylinder while at rest (petcock was not closing positively, either). Must have been doing that for quite awhile.

Fixed that stuff and then drained out all the oil, including the residual in the oil filter. Buttoned up everything and refilled with fresh 10w40. Oil level now correct in the sight glass. Starts, runs fine.

Did my light always take that long? What about you, bountyhunter? How does your's act?

My B4 has about 80k miles on the bottom end, new top end. After a long spell (like a week) sometimes mine will keep the light on for maybe four or five seconds. If I run it every day, more like a second or less. My theory is the bottom end wear (main bearings) is the main thing probably. When the oil really drains down and the engine is dry, it takes a few seconds to pump up. Another really good reason to make sure your oil has plenty of ZDDP, it reduces wear when the engine is dry.

I don't believe it took that long when it was newer, it gradually increased over time. I put a new oil pump in mine so I know that it's not the pump.

Is the additive zddp mentioned on the oil can label? If not, how do you know which oil has it?

:whistle:

bikerjim wrote:

Is the additive zddp mentioned on the oil can label? If not, how do you know which oil has it?

Really good question, it's not on the label. I buy it in little bottles and dump it in myself (ZDDPlus). Diesel rated oils like Rotella supposedly still have it. Racing oils should have it.

Mine actually goes out immediately. In fact, if I'm using the electric starter, the light goes out right after the starter begins cranking the engine over. I'm using 10W40 fully synthetic Mobil-1 motorcycle oil. I've got right around 50,000 miles on it. Ed

650ed wrote:

Mine actually goes out immediately. In fact, if I'm using the electric starter, the light goes out right after the starter begins cranking the engine over. I'm using 10W40 fully synthetic Mobil-1 motorcycle oil. I've got right around 50,000 miles on it. Ed

That explains it... yours isn't broken in yet.