Low Oil Pressure light installation.
A previous post brought up the question, “Why doesn’t the KLR 650 come with a low oil pressure warning light”. I thought a warning light could be done on the cheap or a gauge added at about double the price.
Two ideas came to mind as far as where to mount an oil pressure switch or gauge port.
1. The upper banjo bolt that delivers oil to the cylinder head. This would show pressure downstream of the oil filter at the last easy place before the cams. Trying this idea first, I took a wild guess on E-bay and
bought an oil pressure switch, with banjo mount for $19 delivered. This was listed to fit a ’86-’09 Ninja 250. This would have fit. After taking the banjo bolt off of the KLR, I found that the bolt’s oil hole drilled very small. I believe it was drilled small to act as an orifice. The Ninja bolt has two large holes that would pass much more oil. I wasn’t willing to find out what this would do to the oil system in the real world so it was on to location number 2.
2.The oil pressure gauge port down by the oil level sight glass. If you follow the “bump” coming down from the oil filter cover there is a cap at the bottom. Oil pressure here is after the pump but before the oil filter. This spot is easy to get to, and the factory service manual lists the proper pressure you should be seeing if you decide to mount a gauge. This cap has an O-ring in it for sealing and the threads are 10mm X 1.25. Every oil pressure switch I could find was 1/8” NPT threads. Looking for an adapter locally, all I could find was 10mm x 1. An internet search found a few, but at $20 or so plus shipping, I wasn’t feeling it. Instead the plan was to drill and tap the factory cap. I picked up one from the dealer along with a new O-ring. If you don’t have a 1/8 NPT tap to tap the cap, the auto parts store will have this. A trip to the auto parts store scored a new oil pressure switch too. I just went with a switch I know well. The switch is used on about all the Mopar’s from the 60’s through the 80’s. I asked for an oil pressure switch for a 68 Dodge Dart with a 318. They will ask whether it’s for a light or a gauge. This is for a light. This switch sat a bit too close to the frame for me. There may be smaller ones out there, the counter people were not willing to let me dig through the parts bin. A 90 degree elbow was added for better clearance and protection. Lowes plumbing section has a 1/8” male to 1/8” female elbow. With this the switch sits above the frame under the water pump. If you have an aftermarket bash plate I believe this setup will be well protected.
Drill the cap in the center all the way through with a small bit. I used a #43 bit, .089”.
Drill the top of the cap with a 21/64” bit only deep enough to thread with the tap. Too deep will weaken the bolt head/ shank joint. Clean cap, add O-ring and install on motor.
“Paint” a bit of thread sealant on the male threads of the brass elbow. Thread this into the cap tightening it until it’s facing where you want it. Screw in the pressure switch. This should come with thread sealant already on it.
All you need now is a light, some wire and a “key on” power source.
I have the Vapor dash, so it was easy to use one of the lights from that. Most auto parts or boat shops should have a small accessory light if you need one.
Find a key on power source (like the extra wire “city lights” on first gen KLR’s). Wire this to one side of the light and the other side is connected to the oil pressure switch.
If it’s working correctly, the light should come on when the key is turned on then go out immediately after startup.
Prices and part numbers…
Plug, Drain #92066-1156 $4.06 from dealer.
O Ring 11mm # 670B2011 $ .57 from dealer.
1/8” male / 1/8”female brass Street elbow # 87066 $4.38 from Lowes.
Oil Pressure switch # S310 $6.99 from O’reilly auto parts.
1/8-27 NPT tap #95201 $4.99 from O’reilly auto parts.
Already had wire the light and connectors “in stock”. Add in about $6 tops if you don’t have these.
All in all this was an easy project. If you want to try this do so at your own risk. I’m no expert and assume no liability. Changing a motorcycle out of its stock configuration can and will cause death, dismemberment, void of warrantee AND engine failure. –Tom.