Topic: 1974 K4 Won't Start

[74CB750Rider]

I couldn't get my K4 to fire yesterday. Being the rainy season in Seattle, I haven't ridden in a couple of months, but do try to run the bike every few weeks to keep it going. Last week I removed the windjammer fairing PO had on and ran the bike with no problem. It is always hard to start cold though. Yesterday I removed the windjammer wiring harness PO had spliced into factory wire in headlight bucket and tried to run the bike with no luck getting it to fire. All electrical works with exception that front turn signals were not reconnected yet, but they weren't last week either. Battery is now fully dead from trying to start so I have used kick, which worked before. Any suggestions? Is it possible something related to kill switch? I did not touch the b-b/w wires. Or just coincidence with timing of electrical work?

Thanks for the help.

[DohcBikes]

Well let's see, have you checked for spark yet? The 'ol crystal ball is a bit hazy this morning.

Bike ran, electrical was fiddled with, bike doesn't run. Coincidence? I think not.

[mystic_1]

Well, when failure accompanies recent work like this, it's usually a safe assumption to start looking at the work that was recently done.

First step will be to recharge your battery.  These bikes won't fire well on a weak battery.

If you were inside the headlight bucket, I'd go back in there and check to make sure that you didn't dislodge anything.

A more methodical approach would be to diagnose from scratch, your engine needs fuel, compression, and spark.  Compression is unlikely to be the problem here, and between the remaining two, spark is easiest to check for.  So, pull spark plug #1, then hook it back to the spark plug wire and ground the plug's body against the engine.  Crank the engine and look for a spark at the plug.  Have spark = probably a fuel problem.  No spark = keep looking for an electrical problem.

mystic_1

[Stev-o]

+1 charge battery and check spark.

My K4 likes full choke and no throttle when starting cold. 

[74CB750Rider]

Thanks for the suggestions. I'll get a charger on there and start with the spark. Adding a couple of pictures.

[mystic_1]

Hmm, I'm seeing some questionable solder joints in there, check everything very carefully.

If it were me, since I'm seeing cut wires also coming out of said solder joints, I'd re-do them.

mystic_1

[74CB750Rider]

Yes, I have some work to clean things up and plan to order bullet connectors to fix the POs solder. The only cut wires were to the windjammer harness.

Thanks for the suggestions.

[74CB750Rider]

Today I checked the spark on 1 and did see faint spark. I was checking continuity throughout the wires. The LB/W and O/W wires for turn signals showed closed, which doesn't seem to match wiring diagram. Seems I may now have a short somewhere.