@rolloutred You don't have to remove the radiator. It will be a lot easier if you do.
There's a link for radiator removal near the beginning of this tutorial but the whole procedure might help.
Full Exhaust Installation Here are a couple of other resources i referred to while switching to the aftermarket exhaust. Different systems I have see are similar in the way they install. https://www.hayabusa.org/forum/gen-ii-busa-information/166401-installing-full-brocks-exhaust.html...
www.hayabusa.org
Before you go dropping the oil pan, why not try a different oil pressure gauge switch?
Few facts I learned about oil pressure switch on my ZX-14:
If you expect to screw anything into that boss, you best be sure it has the proper thread pitch and diameter. The sensor on my ZX-14 has ordinary 1/8" NPT threads. They were tapered smaller than a normal 1/8 NPT fitting usually is, I suspect to dissuade owners from using the port in ways other than intended/OEM. I found the same thing with my Yamaha from 40 years ago so it is probably standard procedure to make oil pressure switches with very small thread diameters. There may be a proper adapter you can attach to an oil pressure test gauge but make sure it's tapered small enough for a good fit. There are oil pressure test ports that are intended to be used to test oil pressure. Those test ports probably fall into the normal range of 1/8 NPT thread diameter. I had to use an adjustable die on a fitting to taper the threads small enough to fit the oil pressure switch boss. ---Pipe thread is tapered--get it? Each thread pitch has a normal range of outside diameter. Becuase they are tapered threads, it is possible cut that outside diameter to a smaller range. Thus you have a smaller hole and most fittings with a "normal" O.D. will only go in a half thread or maybe not at all.
The OEM oil pressure gauge is NOT very sensative to reduction in oil pressure. The light probably won't come on until it the pressure drops to ~3 or 4 psi. I have an oil pressure gauge on my ZX-14 and I have varified the extremely low oil pressure required to activate the warning light. That light is useless for anything but startups and maybe cruising at highway speeds if you see the light come on right away. If the switch is working properly and your oil pressure is really that low, I would not run the motor if you don't need to. The oil pressure should run at about 40-60 psi immidiately at startup and then drop to about 14 psi at normal idle speed---that is how my ZX-14 indicates from the oil pressure switch boss. I'd expect the busa would be similar.
Oil pressure switches are always ON at rest, meaning the circuit is closed when the engine is off. When the oil pressure rises above 3 psi, the plunger in the switch opens the circuit and the warning light goes out. It's possible that plunger is stuck. If you try a new oil pressure switch and the light doesn't go out, the problem is not the sensor. No need to test pressure. Drop the oil pan.
I would first try a new sensor. Remeber, the oil pressure isn't normally tested at the oil pressure switch boss--you might not even be able to fit a pressure tester to the oil pressure switch boss. You can buy used OEM oil presssure switches on Ebay pretty cheap. A brand new OEM one is going to cost you pretty much I'll bet. A decent oil pressure gauge should be pretty cheap but just remember, you DO NOT want to thread anything in that hole that doesn't fit. The ZX-14 threads were tapered and they tapered them a lot smaller than normal pipe threads would go.
Buy 3 used oil pressure switches off Ebay. If they all activate the warning light with engine on like the one you have, the problem is not the sensor. The oil pressure is in fact very LOW. Drop pan, find source of obstruction, test pressure at the port(s) designed for that purpose, test oil pressure warning light switch.
Sorry for the longwindedness, I can give you more info than that but point is, you might well not be able to fit a test gauge in the switch boss. I found them to be drilled quite small on both my 08 busa and my 75 Yamaha. The best way to test might be to try another oil pressure switch, just make sure it is not stuck like it appears yours may be.
This pic will show you what I mean. A normal 1/8" NPT male fitting might have a OD that is much larger than the threads on the oil pressure switch. These are tapered threads and it's possible to taper them down smaller than what most fitting typically are. The brass adapter threads were the correct pitch but they were too large. (BTW, probably not the best idea to use a brass adapter on a motorcycle anyway.)
exact kind of bike are we thinking about and whatfor is it built / how is it used ?
