It's NOT the carbs, it's an Electrical problem...

[Colorado85gs550]

I've been fighting a bike that will start and run for 10 minutes then shut off for a month now! I can let it cool off for 30-40 minutes and it will fire right back up again, for 10 minutes.

We originally started with fuel problem because it acted as if it would run until the bowls were emptied and then die. Problem is it never acted like it was running out of gas! It just dies.......I rebuild the petcock, replaced the petcock, cleaned the tank vent, tried with the fuel cap off, I finally removed the carbs and check the fuel bowls when it died and they were still full.............

Here I am! ELECTRICAL......it simply HAS to be. It makes a sound like the starter clutch cycling when it shuts off. It just shuts off when it does it! Like I'm riding along and I hit the kill switch.....only I can immediately hit the start button and it will turn over just not fire and start. I have installed Dynatek Green coils, Dynatek plug wires, NGK D9EA plugs.....but it was working for 3 months after the install of these NEW items.

1) What is the proper way for checking for spark when it does it?

2) What parts of the electrical system would remove spark but not all of the electrical?

3) Where do I start diagnosis?

I've already spent too much to get to this point in the problem. I even cleaned my carbs twice and it's only been a few months since I installed the Dynojet Stage 3 and PODS. I'm getting VERY frustrated at this point.....HELP, please!

[Colorado85gs550]

It's for my '85 GS550EF

[Agemax]

try refitting standard plugs, see if that makes a difference

[Colorado85gs550]

Thanks, but according to the Owner's Manual I am running the standard plug. It calls for the D8EA if the plugs are customed to get wet. It also lists Nippon Denso X27ES-U plug as Standard and the X24ES-U for the wet issue.

[Colorado85gs550]

Would you expect this to be a plug issue?

[Agemax]

Thanks, but according to the Owner's Manual I am running the standard plug. It calls for the D8EA if the plugs are customed to get wet. It also lists Nippon Denso X27ES-U plug as Standard and the X24ES-U for the wet issue.

D9's dont sound like standard plugs to me, try the D8's and see what happens

[Larry D]

What other electrical work have you done ? Have you been through and cleaned ALL the connections, including the ignition switch ? It doesn't really cost anything, except maybe a can of electrical cleaner....Do you have a multimeter ?

Does it happen everytime the bike is started and it will only run for 10 minutes ?

Sounds like your kill switch is on a timer.........

[posplayr]

I would go back to basics

1.) Are you getting spark (use a screw driver near a valve cover bolt and look for an arch when you crank it)

2.) Measure the voltage to the + side of the coils. (use a volt meter to measure either side) If it is low like 10V consider doing a coil relay mod (I would strongly recommend this in any event).

3.) Are you charging when running at 4K RPM at 14V or above.

If it is still cutting out then sounds like maybe a bad coil. but check 1-3 before going there.

[mike_of_bbg]

My bike would die after 20-30 minutes just like that, requiring 15 minutes of cooling time to re-start. It was the ignitor overheating. Either that or the sig gen - but the ignitor is more likely. Dyna S replaced both and the problem is gone.

To check for spark just remove your plugs, replace the wire and lay them against the head so the outside is grounded. Then watch as cranking...

Unfortunately, Dyna S is not available for your bike. You might be able to retrofit one if you get a mechanical advance. You can also look for a used ignitor - but as you can see there are risks with that (you could sell yours and say it came off of a running bike!). +1 verify it's a spark problem though.

[Colorado85gs550]

Larry D, I have a NEW ignition switch but all of the electrical is OEM . It does do this EVERYTIME I start it and I'm down to watching the clock because it will happen right around 10 minutes!


Pos, is there a sticky on the coil relay mod and what am I looking at for expense there? I'll check the voltage at the coils next time it does it as well as for spark....


Mike, are you sure Dyna S doesn't make one for my bike? How the heck would I find out how to retro one to work? It sounds like an overheating issue to me because it only does it once it's warmed up. Runs like a bat out of hell until then though.......

[jbs80106]

probably not much help but...

my 650G manual calls for NGK D8EA or NIPPON DENSO X24ES-U spark plugs.

I would suspect something electrical that over heats after 10mins of running and the can't perform its function(s). What that could be I'm stumped...

[SqDancerLynn1]

No Dyna S for your bike. I would bet you could modify one to fit. You would need a mechanical advance unit from an older model, probably the older style cover Or make a spacer. Seems I remember someone saying you need to modify the advance unit too, to make it sit flush to the crank.
Maybe someone who has do it will chime in!

[Colorado85gs550]

Maybe I have the wrong manual........












OR.....maybe my bike is built so different from the "average" Suzuki that it takes the hotter plug!

This WAS the full fairing model designed for the 600 production-class of RACE that won the championship in 1984.......it must be a pretty HOT motor to begin with .


I'll widdle it down and figure it out.....I'm just NOT an electrical guy. I can fabricate ANYTHING, but ask me to wire it and I turn up my nose....until my ride won't work!

[rustybronco]

As was said before. when it quits, stuff a spark plug in both 3 AND 4 plug wires, lay them on the head, crank it over checking for spark jumping the plug gaps. then, wait ten and a half minutes and check 3 and 4 again.

[BassCliff]

Hi,

FWIW:

Ignitor/Signal Generator/Coil Test

Testing The Ignition System

Diagnosing Slow Cranking

As Mr. mike_of_bbg, I was also suspecting an intermittent ignitor. Good luck. Keep us informed.


Thank you for your indulgence,

BassCliff