Harley won t start

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Oil pressure must be checked with an external gauge that you connect to the same point as the oil pressure sending unit. With the engine at normal operating temperature (hot after 30 min spin), at 2500 rpm or above, oil pressure should be above 20 PSI up to around 30 PSI. It may go as low as 5 PSI on idle with a hot engine but should increase as soon as motor comes off idle. Oil viscosity and ambient temperature will affect oil pressure. If your experiencing this problem only with a hot engine, you may have a big problem in the timing chest. Inner cam bearings are known to collapse (these are smaller than 2007 MY) and the rollers enter the oil pump, thrashing it and causing low oil pressure. If the external gauge (use one that goes to 60 PSI or there abouts) shows correct pressures, then your sender unit, wiring or gauge is faulty. Check this as soon as possible as I have seen engines completely thrashed over this. Ruined engine cases (cam bearing completely disintegrates and cam shaft starts running on parent metal), big ends gone, pistons and barrels, oil pump and cam plate, tappet followers, the list goes on and on. On one engine I have done, I was only able to use the cylinder heads, push rods and covers. Everything else I had to replace. If you find this bearing damaged, make sure that the oil pan is removed and washed out as rollers are picked up by the scavenge side of oil pump and 'pumped' to oil pan, ruining oil pump in the process, sucked back to oil pump and screwing the pressure side, damaging the cam plate, and on and on.

It would not cause, but may b while change cover some wire is disconnected or something lik dat

All four gauges are wired using common supply and ground connections. Oil, Voltage, Temperature and Fuel. If two gauges are not working and stopped at the same time, then I would start by removing the outer fairing and checking the wiring harness. If gauges stopped working at different times, then it is likely either the senders have gone faulty or the gauges themselves.

The sending unit for the oil pressure light is located down at the oil pump. Look under the engine on the right side. The oil pump is located between the engine and the frame.

Good Luck
Steve

Try loosening the bolts holding the front master cylinder on the handlebars. Slide the master cylinder down as close as possible to the right handlebar switch housing. If this doesn't work, the front brake light switch is probably bad and needs to be replaced in the right switch housing.

Good luck
Steve

Replace the starter relay.

to add an oil pressure gauge, you'll need to put the pressure pickup tube at the same place where the oil pressure sending unit is now.

I've seen oil pressure gauges on Big Twins but I don't recall seeing one on a Sportster. I guess I ought to warn you that installing an oil pressure gauge on a Harley engine can cause you to have a heart attack. Why? Because when the engine is idling hot, it has very little oil pressure. The oil pressure sending unit is designed to turn the oil pressure light off at four, yes I said four pounds of oil pressure. The Harley engine is a high volume low pressure system. The reason for this is because it has roller bearings on the crankpin, not shell bearings like *** bikes. So, unless you get an extremely accurate gauge, when your bike is idling on a hot summer day, your gauge will read zero.

Besides, you have the best oil pressure gauge one could ask for in that engine. They're called hydraulic tappets. If you lose oil pressure, they'll let you know very quickly. They'll rattle so loudly that you'll be forced to turn the ignition off.