ZL600 misfires then dies after 1 1/2 miles.

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Benross

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Hello, I'm hoping someone here can help with a problem I'm having with my 1996 Zl600-B1

I've just passed my test and have spent more time pushing the damn bike than riding it. :-(


SYMPTOMS -

The bike starts fine, but after a mile and a half it starts to run rough, not on all cylinders. If you don't keep the revs up, when you pull up it will die and then wont start. If you leave it for 45 mins it will start and run fine, but a couple of miles and it does the same thing.


WHAT'S BEEN DONE SO FAR -

New battery, new spark plugs, new HT leads, new coils, valve clearances adjusted, carbs removed, cleaned, balanced.

Coincidence? -

The last time I took the bike out it cut out and then the starter was just clicking, then it stopped clicking. I shorted the terminals on the solenoid and it turns over so I think its just the starter relay that has given up. I presume this is just coincidence?


I'm not sure where to go next, Its cost me £520 in parts and labour already!
 
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Carbs are a little beyond me, I got the shop to clean and sync them.

When I picked it up from the shop it ran for a good hour but then started playing up, now it does it pretty much a mile and a half into any ride.


I'm in that awkward position where I can't do it myself but don't want to tell the mechanic how to do his job.
 
The shop suggested they may be worth a try, but that they are usually working or knackered, not intermittent.

I changed the main coils myself, are the pick up coils an easy job that I could do myself?
 
I've never changed the pick up coils, but it looks like an easy job. Its in front of the clutch on the right side. It could be a wire that is not broken completely and when the engine gets up to operating temperatures, that "break" does go open.
 
Funny you should say that about the broken wire...

http://youtu.be/54mNJaAleCo

This chaps describing the exact symptoms of my bike, so I'm going to try his experiment and see if I get the same result.
 
I had the same thing going on and it was the pulse coils. When bad they fail when they get hot, then when bike sits & cools down they are ok until bike warms up again. On the 900's you can use the ones from a Concours 1000, so they are easy to find on ebay. Not sure about the 600.
 
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If you do not have a heat gun like in the video, get the bike warmed up so it does die off, unplug the connector for the pick up coils and check the resistance there. Good luck and let us know what you find out.

Bob
 
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I have removed the pickup coils, tried the test but the ohms stayed in the same ball park. I couldn't try on the bike as the starter relay has just packed in so can't start the bike. I've found a replacement pick up coil set on eBay, hopefully they will do the trick...
 
Doe's fuel leak from the carbs if left on prime and not running? Are the plugs wet right after it dies?
 
:hello: My 650 Nighthawk would die after about a mile then start back up & than run fine but it did not misfire. It ended up being the CDI/ECU. On another bike it was doing what yours is doing. Even though the pic up coil tested fine within tolerance it still needed replaced. So it just may be the pic up coils.
 
Not too sure about the '90's models 600's but the '80's models were notorious for a clogged fuel vent in the gas cap. You would simply remove it and have no more problems. I know the gas cap is different on yours compared to the older model so I'm not sure if it has the vent mounted in the cap but please try opening the gas cap and try to go for a ride and see if this helps. If the bike continues to run then you've found your problem.
 
Yeah sounds like a venting or fuel flow problem. Are you running a fuel filter? Later.
 
Sorry, forgot to mention I had tested the venting issue.

I took it for a ride and when it started playing up whipped the gas cap open. Didn't help.


The testing of the coils isn't exact as its hard to recreate the conditions, so I've got a set of pickup coils coming Thursday, will fit them and see what happens.

I will report back what I find...

Cheers for the suggestions and help, I think maybe if I'd done a bit more digging before hand I might have saved myself some money. Atleast I know half the bits on the bike are new and shouldn't give me any trouble in the near future.

Cheers,

Chris
 
All these are great suggestions and I think you are on the right track.

If this persists I would throw an extra spark plug in your pocket, ride until it acts up and then pull the plug wires. Put the extra plug on a wire and ground to the motor. Crank and look for spark, same with other cylinders.

Note what cylinder doesn't fire if any. Troubleshoot from there.
I have also seen coil packs decay from heat. You could swap coil packs from side to side to see if the problem moves from one cylinder to another.
 
Well, I fitted the replacement pickup coils, took the bike for a spin and it had made no difference.

It was down on one cylinder. I checked the exhausts and cylinder 4 was the one not firing. I took the HT lead off and turned the bike over.

(The HT lead has a rubber collar that fits over the spark plug, there is then another rubber bung that is supposed to stop rain getting into the spark plug well I guess)
The spark was jumping out sideways to the engine. I wondered if that was what was happening when it was in position, so I put it back, bike ran rough, I pushed the rubber bung down into the spark plug well, bike ran fine.

Amazed I was!

So it looks like maybe I've spent £560 on parts and labour and the rubber bung just needed pushing down (or maybe a new plug cap?)

Took it for a 20 mile ride and it performed perfectly.

Cheers for the help and suggestions, I'll keep you updated on how the bikes running...
 
:hello: Good lesson learned. You will always remember it. That jarred my memory on a problem I had on a dirt bike some 40 years ago. Glad you didn't through in the towel.
 
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