HELP! Lights turn on but the bike won't start.....

[the81cafe]

Here is what I have: 1981 XS400 Special. I started doing a cafe racer build. The bike ran fine the day I bought it (4 days ago) and now it won't start. I removed all of the rear lights (brake, turn signals and license plate) carefully cutting one wire at a time and labeling them what they were (they being replaced with aftermarket). I kept the negative battery cable disconnected during this entire process. After that I switched the stock handle bars to clubman bars. All of the components were removed one a time and mounted on the clubman bars. My friend was helping me during this process and I wanted to let him hear the bike run. I connected the negative battery cable, put the key in and nothing. The kill switch was turned to "run", the lights and turn signals worked, the horn worked however the bike showed no sign of even wanting to start. It made zero noise (i've been working on cars for 15 years and no the obvious signs of dead or low battery, or when a car just won't turn over and this was not the case). I thought, what the heck, let's wire all of the stock lights back together "just in case". I did that, and the same thing..nothing happened but again, the lights, horn and turn indicator worked. If I turned the kill switch from off to run, I can hear it clicking (assuming this is a good sign). After some reading on the forums for several hours, I learned that the starter button uses the handlebars as the ground, therefore requiring me to sand my new black bars down to bar metal (at least where the starter button housing is). Just to shortcut it, I ran the starter button ground wire coming into the starter button housing all the way to the negative battery cable (1. is this ok?, 2. I figured there is no better ground connection than the negative battery cable). Once I did this, I tried to start it...again, nothing happened (all lights and horn) but no start.
I then read you could "jump" the starter solenoid by connecting a wire from the solenoid to the positive battery terminal, I did this and the motor started to turn over. Since this was causing a spark at the wire, I felt it best not to "push my luck" and stopped jumping the solenoid. I have read a lot about the original fuse box being basically garbage so I replaced it with a modern blade style fuse box using a 20 amp fuse for the main and 10 amp for the other 3 connections. Even after replacing the fuse box and again running my starter button ground wire to the negative battery terminal, no start. At this point, what do I do???? ANY HELP WILL BE GREATLY APPRECIATED!!!!

 

[Arclight88]

Welcome to the site. I am a relatively new member as well, and I have a tech/engr background.

Grounding the starter switch with the wire is sound for chasing the problem in the garage, but I wouldn't leave it that way.

Have you tried the kick-starter yet?

 

[the81cafe]

I tried kick starting it and nothing happened.

 

[Arclight88]

I tried kick starting it and nothing happened.

In that case, it is possible one of the several changes compromised the starting circuit. I would start by verifying the sparking system. If you have a spark circuit tester, install it and kick it over a few times to see what kind of spark you are getting. If not, unplug the spark plug wires, insert a nail in the plug clip on each one, use a clothes pin (or some other clamp) to fix them to the about 1/8th inch from engine block so you can observe them. Then set the motorcycle to start, turn out the lights in the garage, and kick it over a few times. In the darkness, you should be able to observe the spark jumping from the nail to the block.

If you do not see a spark, then it is time to commence working through the several changes you have made. The fuse block may be the cause. If you have a DMM, or a test light, start chasing the connections.

Electricity is merely tricky, but it is faithful. Since your bike ran before all these changes, you will find the issue by being methodical and checking the connections.

 

[the81cafe]

Is it possible that the starter solenoid is bad since the bike tries to turn over when I jump the solenoid to the positive battery terminal?

 

[Arclight88]

It is possible that the solenoid is bad. That said, it alone should not prevent the bike from starting. Right now, my solenoid is burned out, yet I kick start the bike OK. If your sparks are working, and your fuel is on, it ought to start.

 

[kindest]

had you not said you replaced the fuse box I would have guessed that is your problem. Like Arclight says check for spark. If it's original wiring and brittle you could have frayed a wire somewhere. Nothing more frustrating then a seeming fine bike not work.

 

[Arclight88]

TO: kindest: Too right on that!

TO: the81cafe: My previous post only spoke to the case of the negative outcome of a spark test. Allow me to expand.

An internal combustion engine needs air, fuel, and fire to operate. Since your changes were electrical, I replied with that thought in mind. But, if you are getting good spark kicking-over the engine, then you should check fuel flow and the carb fiters for proper fit, vaccum leaks, etc.

 

[the81cafe]

SHE'S ALIVE!!! She fired up today after a little trial and error. Turns out that the starter button was basically shot. It was probably fine sitting in the same spot for 30 years but moving it from one set of bars to another probably disrupted something. I basically took the blue and white wire that was soldered to the button plate (the button pushes into this plate) and connected it with a ground wire and it fired up.
Thanks to those who gave me their input. I'm new to the forum as well as motorcycles and I appreciate this forum.

 

[Arclight88]

SHE'S ALIVE!!! She fired up today after a little trial and error. Turns out that the starter button was basically shot. It was probably fine sitting in the same spot for 30 years but moving it from one set of bars to another probably disrupted something. I basically took the blue and white wire that was soldered to the button plate (the button pushes into this plate) and connected it with a ground wire and it fired up.
Thanks to those who gave me their input. I'm new to the forum as well as motorcycles and I appreciate this forum.

That's great news - good job!

 

[FlyingAnvil]

I have one that is acting up on me, no starter kick only. Have spark to the right hand side, didn't check left side, got tired of kicking it so I am going to try and get the electric start working. It run very good about 4 months ago especially after a carb re-do. Some good info here.

 

[theheadman105]

SHE'S ALIVE!!! She fired up today after a little trial and error. Turns out that the starter button was basically shot. It was probably fine sitting in the same spot for 30 years but moving it from one set of bars to another probably disrupted something. I basically took the blue and white wire that was soldered to the button plate (the button pushes into this plate) and connected it with a ground wire and it fired up.
Thanks to those who gave me their input. I'm new to the forum as well as motorcycles and I appreciate this forum.

I'm having the same problem after I switched handlebars. I came to the same conclusion that the starter button grounded through the handlebars. Any tips on how you got yours fired up???

 

[Wolfe_11B]

Sand/file/grind the spot on the bars where the metal plate is on the control housing. Or do what I did and run a wire from the ground plate to another known ground wire or grounding point.

 

[mtcaferacer]

@the81cafe I am having the exact same issues that you are having. What did you do as far as adding a ground wire? Where did you end up running that too?

 

[Wolfe_11B]

If I remember correctly I just stuffed the stripped end of a wire under the contact point on the switch housing. Ran it to the clamp bolt on the upper triple tree on that side. It's just one way to do it. Cleanest way would be to run a wire from inside the switch housing itself through the harness and just tee into a ground in the headlight harness nest.