Battery issues

[EGDarrow]

Ive read a few posts about battery/charging issues. I just got me a 1986 FJ1200. Its pretty rough. But it runs. Sometimes. It has a new battery in it. It cranks real slow. When it starts, it will hardly rev up to about 4500 rpm before it starts cutting out. When it does rev, you can see the head light get brighter. At idle, going from low to high beam, it is real slow and not really brighter. Does anybody have any advice? I only paid $200 cash for the bike, so its no loss if I have to sink some $$$ into it.

[Urban_Legend]

Hi

Start with the cheap stuff first. Check all of the connections are nice and clean. These have a habit of corroding up and not allowing proper current flow. There is a large RED single wire plug near the battery that can look fine from the outside, but when pulled apart it can be all melted and not in good shape.

Mark

Edit...I see you are new to the group. Welcome. There is an introduction spot where you can tell us a bit about yourself (country, experience etc)  and your bike.

[Urban_Legend]

Sorry. Just realized we are in the Intro spot (Derrrr.) Please tell us a bit about yourself, and how you came to own one of the best bikes ever made.

Mark

[ct7088]

Hi E.G.
The connector Mark mentions carries battery voltage to the alternator/regulator and a poor connection causes the alternator to overcharge the battery shortening its life. That connection is important to check and repair. Check the voltage drop across the key switch by first checking the battery voltage at it's terminals and then check from the negative battery terminal to the fuse block where the headlight fuse is mounted.  If there is a significant drop across the switch don't replace the switch use the switch to control a relay. Most of the members have used two relays one for the headlight and a second to coil power the coils. Using a single 30 amp relay(or a 40 amp) from the battery to the wire powering the fuse block, the ignition switch will energize the relay using the wire that did power the fuse block. I'm pretty sure this will help the headlight problem and may help the running problem.

Chris

[EGDarrow]

It could end up being a parts bike for someone. I would HATE to do that. But Im finding parts for these older imports are fairly cheap in price. So why not keep them on the road. And that is my goal for this rocket.

[FJmonkey]

Welcome EG, some of what you mention may not be battery related. Slow cranking when hot is a common issue for the older 2 brush starters and just for a starter with lots of use. If the slow cranking is cold then it might still be a starter issue. The cutting out sounds more like a dirty/clogged carb issue. If the bike sat for more than a month the carbs may need deep clean. Not just stuff you pour in the tank and hope it gets better. The brightness change is a result of the alternator doing its job. It won't produce much if any power at lower RPMs. That is why it gets brighter when the revs get high enough. You might have some fellow members near by, post up your general location and see if anyone bites. These FJs are really easy to work on so $200 for a running bike is a great deal, even if she has some warts and scars. Check the red connector, if you are not sure then this post will help. Scroll down till you see it...

http://www.fjowners.com/index.php?topic=16107.msg162608#msg162608