My bike and I have quite a history. I bought her about 20 years back, left her standing in the garage when she failed to many times and got her back in shape about 2 years ago. I haven't been riding a lot the last 2 years (something having to do with having a family and building a house). When I did take a ride, she didn't run really well. First time she started on one cillender. picked up to three rather quickly, but the fourtht took really long to kick in. I also seemed to miss some power. One day I heard a terrible noise when starting the engine, a low noice coming from the carter. I switched her of immediately and didn't dare to try again.
I recently moved to my current house, so I had to find a mechanic. Luckily I found a really good one! Thankfully it was 'only' a boult (or 3 out of 4)in the dynamo (stator) someone forgot to thighten... Easy to fix. He did some other work for me aswell and synchronised her for me. After that she was running beatifully like in her early years with me!

I few weeks a go, she all of a sudden left me standing. The engine just died and she wouldn't start again. Just before that happened, she had some hickups when I aproacht a traffic sign. The engine died, but I could restart her quickly. Less than 500mtr later, the engine died again. When I tried to start:
- all dashboard lights where bright
- I could easely do several attempts
- I could smell gas
- I could hear the startengine run
- I could hear eh... how would you discribe the noise you hear just before the engine turns on?
- I could hear 'backfire' or somekind of popping sound in the engine
but she didn't start.

So I think:
- power is OK
- fuel is OK
- sparks OK

I thought it had to be the carburators. They hadn't been cleaned in 33 years. She has been standing outside in de the rain and I have used the wrong type gas once or twice (but not the last at least to times I fuelled up)
Cleaning the carbs didn't do the trick. So I have checked:

- wiring startingcircuit
- pick-up ...
- coils (?, bobines in Dutch)
- sparkplugs, tested outside on the cillinderhead to be able to see the sparks (nice blue)
I have tried starting her with breakcleaner, she wouldn't. So that leads to think that is has to do with the ignition, but what?

When I try to start the engine it sounds like she could start to run any second. But she just doesn't. I have several video's of it. I'll see if I can upload them later.

What on earth could it be?

 

Oh my favorite rider, ItchyBoots is from Utrecht. She just started season 6. You're in good company man. Welcome to the forum. We'll look to see the videos and see where we go from there.

 

Video of attempt to start the engine
Hope this works.

This video is of yesterday's attempt to start the engine.

 

@Suuz Is it just me, or is no one else hearing any audio?

 

For some reason the video uploaded without audio. I'll try again this evening.

 

Video with sound

Hope this works then.
In this video you can hear my last attempt to start the engine. So close!

 

@Suuz Thanks for posting again. It certainly seems like a fuel starvation issue. When you say that Fuel is ok, what makes you think that? In looking at the wiring diagram for the 87 600, the fuel pump is wired just like the one in the F3's. Power to the fuel pump has to be supplied via the Fuel Cut Relay. That is the Black wire which I've highlighted in this wiring diagram. The Yellow Blue wire is the control signal for the Fuel Cut Relay. I highlighted it as Light Blue since I don't have multiple colored lines. When the relay turns on, the fuel pump turns on. When the relay is off, so is the pump. Well, this relay does not just get turned on (like you would think), it gets turned on and off in rapid succession. So the fuel pump receives a rapid on/off signal. You can see that the Light Blue highlight originates from the Spark Unit which is controlling the Ignition Coil for cylinder 1 and 4. The Fuel Cut Relay is located near the battery. If you unplug the connector from the Fuel Cut Relay and put a jumper across the Black and the Black/Blue wire, that will cause the Fuel Pump to run as soon as the Ignition Key is turned on (don't leave it this way, only for testing). This way you can ensure that the fuel pump is running and that you're getting fuel to the carburetors. The Fuel Pump will not continuously run. It will run until the bowls fill and the Float Valves close, stopping the flow of fuel. Once there is a build up of a little amount of fuel pressure, the pump will stop. It is a Low Volume/Low Pressure fuel pump. Since you had them recently serviced, the bowls may not be getting filled up if the pump is not working properly.

Read this over a couple of times to digest it. Let me know if you have questions and what you're able to diagnose.

https://www.partzilla.com/catalog/ho...ne-600/battery

 

So, if I understand correctly, I bypass the relais to test the fuell pump. I don't have to start the engine, I only have to turn the ignition key.
​​​​​​What am I looking for when I do that? Do I visual check for the bowls to fill?

 

@Suuz I'd listen for the pump to run. It's ok to start the bike, or try to start the bike. The link in my signature was done quite a few years ago (ok, I just checked and it's been 12 years), but there is a video in there that will give you an idea of how the pump sounds when it's running. The contacts in the pump burn up after a few years and need to be replaced. I'm not saying that is your issue, but it's possible. In the video, the pump is not connected to the fuel lines and that is why it will keep running. If fuel was in the lines, pressure would build up and it would stop. The pump from the 1987 has a different part number, but wouldn't be surprised if it was the same, but with different connector. How they function is the same though. You can put your hand on the pump and feel it run. The goal is to make sure you're getting fuel into the bowls of the carburetor. You can loosen the drain screw on the bottom of the float bowl and verify that gasoline is in them. I'd put a good size rag under them when you do check as it's going to dump gasoline on your engine.

 

Tested the fuelpump today. And checked it with my 'bible' (also known as Haynes). Pump is working fine: sounds like it should and pumps enough fuel too.

So I believe it has to be something in the startcircuit (ignitioncircuit?). Maybe the coils? I measured the resistance of the [forgot what it is called] it was fine. Or the coil cables? I wasn't able the measure the resistance of the cables. But I did test the ignition with the spark plugs outside the engine and it fired blue and regular, so that should be fine to.
I have an spare set of coils, gonna try them tomorrow anyway and see what it does.

Anyone an educated guess of what could be the problem?