Author Topic: '86 K75c Won't start. Yes, I tried that stuff. Any help? (Read 18470 times)

punchesdfw · « **on:** August 06, 2018, 06:36:09 PM »

New battery. Humming noise in tank. Fuel. Spark, umm don't do that with the plugs out! YIKES! Hot-foot! Side Stand up. In Neutral. Pull the plugs and they are wet. Any other ideas?

Laitch · « **Reply #1 on:** August 06, 2018, 06:58:53 PM »

How long have you owned this bike? How many miles are on the odometer? Has it ever run well since you took possession of it? How many trouble-free miles have you ridden it? Have there been any modifications to the moto? How old is the fuel in the tank? How many miles on the plugs? What do their gaps measure? Do the plug wires fit tightly on the plugs or do they wiggle? Do the headlights operate? Do the turn signals operate? How about posting a few photos? Hot enough for you?

On a K75, the side stand position doesn't control starting; the moto can be started when the clutch lever is pulled in regardless of the gear position.

The Mighty Gryphon · « **Reply #2 on:** August 06, 2018, 06:59:11 PM »

It could be flooded. Once the plugs get wet enough to not fire, the injectors will just keep pumping fuel into the engine.

I unplug the tank connector behind the right side battery cover and crank the engine for 10-15 seconds with the throttle wide open to blow the gas out of the cylinders. With any luck, once most of the fuel is blown out the engine will fire a couple times and die.

Plug the tank connector in again and try to start again. Make sure the throttle and "choke" are closed. If no start, put the choke in the first position and try again. If the problem was a flooded engine, it should now start.

punchesdfw · « **Reply #3 on:** August 06, 2018, 07:35:07 PM »

Thanks to the Mighty Gryphon. Did as suggested and it ran for a bit and shot fuel about 15-feet across my shop! I'll let it sit for a bit and try it again. Thanks!

The Mighty Gryphon · « **Reply #4 on:** August 06, 2018, 09:19:16 PM »

Never open the throttle when starting a brick engine. The only thing it might need on a cold morning is the "choke". Giving the engine any throttle when cranking will flood the engine. If you have a throttle lock "cruise control" you might want to make sure the throttle is fully closed before cranking.

No need to get into the details of how I learned this.

punchesdfw · « **Reply #5 on:** August 06, 2018, 09:50:35 PM »

Here's the crazy thing it's been running smoothly at 3000 rpm for 20-minutes with the fuel pump unplugged! WTF? When I plug it back in, it won't run at all. Argh!

The Mighty Gryphon · « **Reply #6 on:** August 06, 2018, 10:28:03 PM »

Quote from: punchesdfw on August 06, 2018, 09:50:35 PM

Here's the crazy thing it's been running smoothly at 3000 rpm for 20-minutes with the fuel pump unplugged! WTF? When I plug it back in, it won't run at all. Argh!

????????!!

punchesdfw · « **Reply #7 on:** August 06, 2018, 10:30:04 PM »

That's what I said! I have absolutely no idea what's up.

The Mighty Gryphon · « **Reply #8 on:** August 06, 2018, 10:42:05 PM »

Are you sure the fuel pump is not running when you unplug the tank connector?

The Mighty Gryphon · « **Reply #9 on:** August 06, 2018, 10:44:19 PM »

Is the bike a cafe racer? Has it been modified? How long have you owned it? Has it run properly before today?

punchesdfw · « **Reply #10 on:** August 06, 2018, 10:46:04 PM »

Now that's a good question. Completely stock. Maybe the previous owner did some hotwiring. I'll check under the tank in the Morning. Thanks!

punchesdfw · « **Reply #11 on:** August 06, 2018, 10:47:49 PM »

I've only had it 2-days. Needed a battery, so I bought a new one. Heard it run when I bought it

The Mighty Gryphon · « **Reply #12 on:** August 06, 2018, 11:04:05 PM »

When you say it shot fuel 15 feet across your shop, I assume the fuel was shot out of the exhaust. Am I correct?

punchesdfw · « **Reply #13 on:** August 06, 2018, 11:24:32 PM »

Yep! Raw gas!

The Mighty Gryphon · « **Reply #14 on:** August 06, 2018, 11:49:47 PM »

So the engine ran for 20 minutes with the fuel tank unplugged? Was the fuel pump running during this time? Can you see fuel returning inside the tank when the engine is running?

Can you post a photo of the connector you unplugged to get the engine to run?

punchesdfw · « **Reply #15 on:** August 06, 2018, 11:51:50 PM »

Past my bedtime. I'll get it in the Morning. Thanks for your help. I really appreciate it!

Laitch · « **Reply #16 on:** August 07, 2018, 02:22:01 AM »

Quote from: punchesdfw on August 06, 2018, 09:50:35 PM

Here's the crazy thing it's been running smoothly at 3000 rpm for 20-minutes with the fuel pump unplugged! WTF? When I plug it back in, it won't run at all. Argh!

A photo of the connector you're manipulating would be helpful.

punchesdfw · « **Reply #17 on:** August 07, 2018, 10:05:58 AM »

Here's the connection.

The Mighty Gryphon · « **Reply #18 on:** August 07, 2018, 10:35:36 AM »

And when it's unplugged the pump and the engine run. Is that correct?

punchesdfw · « **Reply #19 on:** August 07, 2018, 08:30:42 PM »

Yes! Crazy huh?

The Mighty Gryphon · « **Reply #20 on:** August 07, 2018, 08:35:48 PM »

I would be pulling that tank and trying to find what the heck is going on. Is there another fuel pump somewhere?

punchesdfw · « **Reply #21 on:** August 07, 2018, 08:37:35 PM »

Don't know. I just got home from work. So, I'll take a look in the morning. Thank you so much.

John Lang · « **Reply #22 on:** August 08, 2018, 06:56:41 AM »

There are 2 4-pin connectors under the seat. Make sure you have disconnected the correct one, not the one to the gear position indicator.

The Mighty Gryphon · « **Reply #23 on:** August 08, 2018, 08:28:13 AM »

Quote from: John Lang on August 08, 2018, 06:56:41 AM

There are 2 4-pin connectors under the seat. Make sure you have disconnected the correct one, not the one to the gear position indicator.

Good point, especially if the tag that says "tank" is missing.

punchesdfw · « **Reply #24 on:** August 08, 2018, 02:18:57 PM »

OK. Now I'm pissed! Pushed the starter button and it fired right up. After a minute or 2, it died like it had been switched off. Now it won't start!

UPDATE! Here's the CRAZY ting. I removed and reinstalled the tank. Pushed the starter and it ran for 15-minutes before I turned it off. I Pushed the button and turned it off several times and it runs perfectly?
Seems to be OK now. I have No Idea what just happened!

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Author Topic: '86 K75c Won't start. Yes, I tried that stuff. Any help? (Read 18470 times)