1986 K100RT cafe racer build

[bclow]

I'm in the process of cafe racer-ing my bike, but when I removed the insanely bulky dash unit (speedo, tach, dummy lights, etc.) the starter would not work. I have the manual and I've been trying to figure it out but I'm REALLY bad with wiring..nearly no knowledge whatsoever. If anyone could offer some advice on how to remedy this it would be greatly appreciated! oh btw I'm not putting a new speedo on it yet, I have caps for any excess wires, I just need to get it running! Someone suggested that since it couldn't detect neutral I would just have to pull in the clutch to start it, but even with the clutch pulled in it won't try to start at all, so there must be some other issue. The wires all go into one of two connectors, respectively, that plug into the back of the dash unit. The bike works if one of them is plugged in. The one that causes it to work is labeled 1-12, each of the numbers are identified in the manual. I'll list them out here:

1--Leads to fuse 3, from there, goes to the starter relay, load shedding relay, and ignition switch. (I figured this and #5 might be causing the problem but I don't know how to make it work)

2,3,4--Gear position switch
5--Starter switch

6--Leads to a connection for additional instruments, as well as the rear brake switch, front brake switch, and clutch switch

7,8--Fuel level sensor

9--Alternator

10--Temperature sensing unit

11--Oil pressure switch

12--Choke Switch

[rbm]

The bike should start with the instrument cluster off and pulling in the clutch handle. If it doesn't, then your clutch switch which is acting up.  Make sure the clutch switch is operating properly by testing it with an ohmmeter.  The clutch switch connector is under the tank, on the left side.  Disconnect the connector and test continuity between the two pins.  It should read open circuit with the clutch lever out and 0 ohms with the clutch pulled in. 

If the switch checks out, check the condition of Fuse #1.  The clutch switch is supplied power from fuse 1 and if it's blown, the starter relay will not get power needed to work.

BTW, without the instrument cluster in place, the alternator will not charge the battery and you'll quickly kill it.  Make sure to build a charging circuit for the alternator using two 56 ohm, 2W resistors, getting switched power from the Connector for Special Equipment for example.  the other end of the resistors will attach to the blue wire leading to the alternator (pin 9)

[bclow]

Thanks so much rbm, you're a life saver. I'm new to motobrick & didn't really know what to expect, I really appreciate such a quick response! Once I get'r runnin again I'll post a pic on here. I always love seeing pics of other people's bikes in these threads, hopefully someone gets a kick out of it

[klhoskins]

Hey Bclow, this site was a lifesaver for me on my café build. Good luck and cant wait to see the pics!

[bclow]

Here's how she sits so far. Up next is ignition relocation & headlight adjustments, then shortening the frame and getting the seat modified. Any suggestions or tips are always appreciated!

[rbm]

My advice.  Don't modify the Corbin; it'd be such a shame to change it.  Rather, sell the Corbin and get a stock seat pan to build up your ideal cafe seat.

[bclow]

Hey Bclow, this site was a lifesaver for me on my café build. Good luck and cant wait to see the pics!

much appreciated klhoskins! I'll be posting more pics soon, she looks better every day. Ill put up a pic of what she looked like when I first got'r too.

My advice.  Don't modify the Corbin; it'd be such a shame to change it.  Rather, sell the Corbin and get a stock seat pan to build up your ideal cafe seat.

rbm, that was my first idea and honestly I'd forgotten about it so I'm glad you suggested it. That might be a way into the future, but that's probably what I'll do.

Well guys, good news and bad news. Good news is that I relocated the ignition, lowered the headlight, and managed to take apart the extra front light/turn signal combo in order to utilize only the turn signals (in the picture I posted you can barely see one of them under the headlight mostly blocked by the handlebars. They're bullet style, which I like, but the extra lights were unwanted). The bad news came from the previously mentioned front turn signal modification. When I removed the extra lights, only the rear turn signals would work at first. However, two wires came from each of the extra lights, and by connecting each of them to each other, respectively, the front signals began working. Glorious as it felt to get them working, I am now blowing fuses 1 and 2 immediately upon turning the key. I'm assuming that something was going on inside of the extra lights that I am not aware of, but like i mentioned at the beginning of this thread, I know nearly nothing about electrical work. My uneducated guess is that since the electricity that was being used to power the lights no longer is, it is overloading the circuit. But I have no idea how to fix that, nor if it in actuality is the issue. Any ideas?

[rbm]

Turn signal live wires are Blue/Red (Left Signal) and Blue/Black (Right Signal).  Other side of the lights are connected to Brown (Ground). Signal lights on a given side of the bike (Left or Right) should be paralleled together, and not serially connected.  Power for the signal lights is coming from Fuse #7.

How you blow Fuse #1 and #2 is a mystery.  Fuse #2 is connected to Grey/White and is dedicated to the parking light circuits. 

Can you draw a schematic of how you've wired up the turn signals?  It's impossible to diagnose the error in the circuit without understanding how you've modified your harness.

[bclow]

rbm, as always, I very much appreciate your rapid response. But I'm happy to say that through some research and bouncing ideas off of my old man I managed to work it out. So! what happened: The issue actually began about 4 months ago, back when I dug into my first real project on the bike, changing the handle bars. When I took off the old bars I removed two wires used by the grip warmers. Not really knowing what to do with them, I went to the auto part store and got some wire caps. That was the beginning of the end, so to speak. For those who, like myself at the time, don't know, typical wire caps contain a small metal tube which the wires are pushed into, then clamped down on with pliers. Metal, being the key to my demise. So fast forward to yesterday. When I removed the extra lights and the black rubber switch mount that held the ignition switch, I used the caps to seal each GROUP of wires together. So the wires for the hazard lights were all combined and grounded via the metal end of the wire cap, as were the wires for the grip warmers and the extra lights. That's what was causing the fuses to blow, thus not allowing the bike to start. I removed the caps, put electrical tape around the ends of all of the wires individually (except the extra light wires, which I taped together in order to complete the light circuit) and she runs right as rain without blowing fuses. Very exciting! To celebrate, I'll post some pics---

The horns, yes plural and very large, are jerry-rigged at the moment because the headlight blocks them from where they used to be mounted. If anyone has any suggestions of where to put them let me know. Also, a mechanic mentioned to me that he didn't think messing with the exhaust pipe would be a good idea...he said that he wasn't sure about this bike, but that it might adversely affect the fi computer. Anyone have any knowledge about this? I was planning on cutting it down.
 If anyone has any questions about anything I did, feel free to ask away, I'd love to return the favor done for me & save as much headache as I can.
She's got a big booty! Can't wait to move on to trimming the back half of the bike. And as promised, I've attached a pic of the bike when I first got it. I still have all the original parts minus the rubber switch mount, and I'll sell anything not on the bike. Enjoy!

[darthbane71]

Damn, I'd kill for that seat. Way nicer than mine. Please don't tear that one up lol