Quote from: Tim.y.95.uk on January 13, 2026, 11:37:36 AMHi everyone. So i have a 1990 fj1200
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.
can anyone please help me

Tim,

Disconnect one terminal of the healthy 12 Vdc battery in the bike. Connect a small 12 Vdc light bulb (or test light) from the empty battery terminal to the battery terminal lead.

If all is well, the test light will be OFF when the key is OFF. If the light illuminates, with nothing ON, you are seeing your problem. Go to the fuse block (and maybe the relay panel) and disconnect one fuse or relay. If the light goes OFF, your problem is on that circuit.

Remove and re-connect one fuse or relay at a time, to find the circuit that causes your problem. If you disconnect any fuse, relay, or plug, and the test light goes OFF, your problem is downstream from that point. Following the wiring diagram, disconnect and re-connect the plugs that lead from that fuse or relay, to the problem area. Anything that you move, that causes the test light to go OFF, is some part of the problem.

If the problem area is the horn, for example, disconnect the horn from the wiring. If the test light goes OFF, you probably have a bad horn, or bad wiring from that last plug to the horn.

A wire may be chafed where it is tied to the framework, so once you know where, release the wiring from the ties to the  framework there. If a wire has damaged insulation, the auto parts stores sell liquid wire insulation in little cans. Separate the wires, and apply liquid wire insulation as needed. Allow the liquid to dry. Secure the wire bundle to the framework in ways that are kind to the repaired wiring.

If the test light near the battery comes ON, but only dimly, then you have a high-resistance short somewhere. Anything you do to make the dim light go OFF is related (on-track) to the problem. HTH.
.

FWIW, my local public library has a 3D printer. For their members, they will 3D print anything smaller than a two quart (two liter) milk jug, for the cost of materials. High temperature items will cost a bit extra, sure.

Just bring your .STL files in on a flash drive. You can edit 3D objects on Tinkercad.com if needed.  I found some .STL files for bike parts on an Internet library in Europe.

My local library teaches classes on 3D printing for a small fee, whenever enough people sign up. Gonna do that.
Never mess with a librarian, they deal in information. 

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.