I really dislike electrical gremlins. I have learned the hard way not to throw parts at electrical problems, it gets expensive.
Here is a current flow diagram which can help you understand what's going on..
https://fjowners.com/index.php?topic=18991.0
Also, in the back of your owners manual is a color coded diagram on your electrical system.

Get a 12v test light or multi tester, figure out where the power is interrupted, start at your battery and go to your starter relay and on from there. Step by step.

Current drain: A problem area I've seen is the 12v hot power lead down to the horn. The 12v power to the horn is continuous so the horn activates when the button is pushed which grounds the circuit. The wire insulation can get chaffed from rubbing against the steering neck...normally this will blow a fuse but a very slight partial ground fault can drain a battery without blowing the fuse.

Cheers. Pat

Hi everyone. So i have a 1990 fj1200, when I purchased the bike she had been sat for do long i cleaned her up and given some tlc.
Long story shoet passe mot with weak battery but within a day or two it needed to be jumped every time I started her even dure in time of use because I was looking for a car.
The bike took me and a freind on a 1500 mile trip from home to thurso the nc500 and back the next day started for work but the day after.. started and died no power at all wouldnt jump.
I braught a new battery changed fuses in the fuse housing a new ignition, and voltage generator ad i believe that's where the rectifier is located aswell i still have no power can anyone please help me

Yeah I don't have a 3d printer, I emailed the guy and he said it's heat resistant to 230 degrees so should be fine but I may wrap it in some heat shield anyway to be safe. I like that having this disconnect it makes pulling the carbs easier

I remember seeing that listing. Since my household had a 3d printer I just made my own model and print, Using Glass filled Nylon (A high temp polymer) you can make your own for about 7 dollars. But unfortunately that requires already having a quality 3d printer. For those not wanting the hassle of DIY that one is a good option.

Steve,

Just wanted to add, when the time comes to actually buy handlebars, most right-side-up bike shops will let you take new handlebars out to your bike. Make a (NO TOOLS) test fit on the parking lot, one bar at a time. Good chance they will have the right stuff to fit you, after a few tries.
Just for future reference . . . 

Dean, on the internet I have been looking for FJ engine guards and ran across,
https://www.fjownersclub.co.uk/product-page/fj1100-1200-engine-bars
are you familiar with this group?  I have been inclined to join, which is required to purchase the engine bars and other items that they sell.

Steve

Quote from: Millietant on January 11, 2026, 07:52:54 AMIf anyone wants to buy parts this side of the pond and get them shipped to me, I could send them on to you to avoid the import hassle.

A very kind offer Dean...You're the best!

If anyone wants to buy parts this side of the pond and get them shipped to me, I could send them on to you to avoid the import hassle.

FJowners,
Just a quick note to add that Europe and the UK have lots of FJs on the roads over there, and they still have many good sources for FJ parts. They also have independent 3D printed plastics (or the .STL files for making them). You may want to join a few FJ forums across the pond, for better access to the non-USA FJ parts. Beware of any shipping and tariff charges, of course.
 

You have offered a lot of alternatives. Thanks!
I am only at the initial stages of learning what needs to be refreshed, renewed or replaced, and whether the engine will turn over or needs further work.  So a lot of discovery remains. 
Today was spent dismantling the front brake and clutch reservoirs.  Both exteriors are pretty weathered and have lost the white painted lettering on their covers.  My plan is to clean up and repaint the exteriors of the reservoirs and use kits to rebuild the innards, and also replacing the hydraulic lines. 

The Buell pegs look great and I will replace the Yamaha pegs with them to gain that bit of additional leg space.  That assumes, of course, that those Buell pegs are still available, which has been a problem with sourcing steering modifications.  Randy at RPM has steering risers, which may help.  Also, I will be trying the ABM Superbike Handlebar Conversion Kit for the Yamaha FJ1100 1984~86, which I purchased from Bikermart in the UK.

Steve