Greetings, In the process of safety wiring my rc390 and have a question for anyone with an answer... Looks like the coolant cap for this bike can't be drilled due to its size/shape. What have others done with this issue? Also, the oil drain plug containing the filter screen...that's also a bastard to drill as it is hollow. Can you get away with siliconing that? Cheers! Aaron
Might have to run an aftermarket rad cap that is a more traditional shape and easier to drill. Same with the drain bolt, definitely need to figure a way to wire that. They've been doing it since 2015 in MotoAmerica so you're not the first. I've only ever heard of silicone on an oil drain bolt as a mercy for first-day racers, and that's only if the tech inspector has had coffee. We have a couple of people that race these bikes so maybe they will chime in.
the 390 does have a hollow bolt but totally able to drill it as pictured above or just straight through (left to right) halfway up closer to the top. i have done a few of these as race prep. as for your rad cap you can drill the rounded lip. basically where you would grip it with your hands is where i am talking about. i have done that as well in the past
