Checking coils OFF of the bike

[Suzuki_Don]

Tip a teaspoon of fuel in each sparkplug hole, replace the plugs and see if it will run for ten seconds or so.

If that doesn't work then I would say your timing is off. Either cam timing or ignition timing. Check the wiring to your coils against a wiring diagram for you model and make sure the correct primary wire is going to the "+" side of the correct coil. If these wires are going to the wrong coils then the spark will be occurring when the piston is at BDC or on the exhaust stroke.

Report back.

[Flyboy]

The fact that you mention the plus are dry, and yet there is fuel in the float bowls would point to the fuel not making it from the float bowls up into the venturi where it is mixed with the air and delivered to the motor.
So sounds like a carb problem to me, also supported by the fact that it has on occasion tried to fire up and then die off, points to fuel starvation all the way.
Start by checking your float levels, if they are too low, then this lean cut is the sort of thing you will get if they are too high you will experience a rich cut, but by all you have said, I don't see that being the problem.
These carbs are fussy about their float levels, also check to make sure that the bowls are venting properly, so you are not getting a vacum in there, which is stoping fuel flow.
Failing that, I am afraid, re-strip, re-clean, it just takes one little port or channel to be blocked and it is all over, red rover.
Keep at it, we have all been there, done that.
Keep us updated.

[bighamms]

@ all.... Ok, so i spent a little time this morning messing with the bike. I took both plugs out and again, checked for spark by grounding on engine casing. Spark was really good. I had reported that my plugs are dry when i pull them out. This morning, I tried starting the bike several times. When I pulled the plug out after several attempts, I felt the plugs and sure enough, they do have fuel on them. I even dried them with a cloth and reinserted them, hit the start button several times and then pulled them back out. Looks like there is fuel getting to the plug.
I also followed suzuki Don's advice and put a little fuel down each plug hole. The bike did not fire up, but it did backfire a few times. Which is more than it has been doing.
At this point, I think I want to investigate timing issues before I take the carbs back off again. Need some practical instructions on checking Cam and ignition timing. Just to clarify, i have checked the wiring to the coils against my manual. I'm about 99.9% certain all wiring is correct coming off the coil.
*Noteworthy... I took off the cover for the signal generator (right side of engine). It was extremely clean in there and all wiring looked good. however I did notice that one screw looked stripped. so somebody has been in there messing around at some point

[bighamms]

ok, so i am still messing wtih this thing before having to get to the office. I've taken off the tank and spent a little time going over all the connections. for the most part, i've disconnected each one, and cleaned with a piece of sandpaper. there were a few wires that showed some corrosion near the connection (white and crusty). I clipped those bullet connectors off and replaced with new spade connectors. Also replaced 1 spliced wire wrapped in electrical tape with a new coupler. I really didn't do much to any of the connections inside existing couplers, other than just visually inspect them. All of those connections were surprising clean. None of the wiring was brittle or stiff.
Because it was suggested that the issue could be gas/carb related, I rigged up a temp tank. I did this to eliminate a possible faulty petcock (also, my petcock does not have a PRIME position. When trying to start the bike with temp tank, it never fired up, but did backfire quite a bit....a few of which even made me jump they were so loud. This may be important, but right before it backfires, it kind of bogs down a bit. The smaller backfires are coming back through the carbs and if open my airbox, there is some faint white smoke lingering around. the loud backfires, are coming out of the tail pipes.
** In order to eliminate a week battery as the possible culprit, I've hooked up my charger to make sure i'm getting max cranking amps....

What should I try next????

[Sparky]

If you suspect the battery is too weak try jumping it?

[bighamms]

@sparky.... my battery is new and appears to be functioning properly. But, because I am constantly hitting the start button it drains the battery pretty quickly. So I have my charger/jumper hooked up pulling double duty while I test all the suggestions I get off of this forum.

Just to update....nothing on the bike has changed, however, my level of frustration has grown exponentially.

[GSX550]

If it is backfiring like that I would suggest that you have the plug wires swapped and messed up or you have swapped the trigger lines for the coils.

This would mean that you are firing spark at the wrong time and you would get all sorts of backfires, pops and farts but no running.

Kind of like when you put a distributor on a car 180 degrees out, that is what swapping the trigger lines would do.

It'll take about 5 seconds to swap them over and give it a try. Also triple check that you have the spark leads correct - 1 and 3, 2 and 4.

[bighamms]

@gsx550... my bike is a gs450s. It has (2) single tower coils. So each coils only supplies spark to 1 plug. It's been recommended several times that I double and triple check the primary wire to ensure proper connection. the wiring on this bike seems pretty easy to follow. Coil 1 has a orange and black/white wire soldered on one end and it terminates in a male coupler on the other end. That male coupler then attaches to a female coupler with the exact same color scheme. Coil 2 has the same setup, only the wires are orange and white...which I assume is to help avoid incorrect hook ups.. I did try to simply switch the plug wires (left coil to right plug and right coil to left plug), that did not seem to make a difference.

i don't know much about timing, but it seems like that is the next logical step. Maybe the bike is out of time and that's why is doesn't fire. Any suggestions on testing the timing??

[scottychop]

Wow.

You've certainly gone through everything and still got a mess. It has got to be timing related. NOTE: the PO on my bike had "tinkered" with the signal generator and spark advance unit also. He "accidently broke off a piece of the unit and replaced it with a drill bit. I would take out he whole unit, clean it up, and make sure your spark advance is opening and closing, as well as looking around for missing parts.

That said, I am pretty certain the gremlin's in your harness somewhere. There's just not a whole lot left, other than rebuilding the carbs again. Oh, and if you do that, make sure that your parts match up left to right. I have had a number of carbs that were fooled with not the same. Diaphram springs were different lengths, jets different....

Have you checked to see if your choke is working properly????

Scott

[GSX550]

Sorry, my bad.

Backfiring and farting definately does sound like timing. There hasn't been any changes to other parts of the wiring for the ingition has there? Is this bike solid state or points? If solid state and someone was trying to rewire or fix some corroded connections they could have mixed something up....Maybe.

If it is points, do a static time of the engine, with a light to make sure that you are at least sparking somewhere near the correct time.

Electrical gremlins are always the worst....

[bighamms]

@ scotty.... hey man, nice work on the megabuild. I was just going over your posts and am definitely hoping to move in that direction. Not a lot of cafe's in my neck of the woods, so I would like to build the nicest one around and the gs450 seems like a suitable platform.

Ok, down to biznass....i am also thinking that it is timing related. This is my first build, so I don't really know how involved timing is. Can you give me some simple step by steps. the signal generator and spark advance is under the cover on right side of bike...correct??? I will open it back up tomorrow and pull everything out.

as far as the carbs are concerned. I've completely torn them down on 3 separate occasions. The last time, I laid ALL carb parts side by side on a large with piece of paper to compare parts (i'm a method guy). I did this because the first tear down yielded a different size main & pilot in carb 2. I've since rebuilt the carbs to spec and the last tear down was just a verification of some notes that i had made. so i feel like i have eliminated the carbs as the issue.

aside from the sig gen and advance, are there any other timing related parts that should be investigated?

[bighamms]

@gsx... Changes to ignition: I put a new ignition switch(start button) on the handlebars because the original one was broken. After replacing that switch, I discovered that the solenoid was bad (thanks to the guys on this forum), so I replaced it with a brand new unit. I've owned the bike for about 3 months and have only been able to fire it up a handful of times. It almost seems as if it fires up when all of the circumstances are exactly perfect (ie. sun, moon and stars are all aligned). but it's so rare, and I get so excited that I always fail to document exactly what I had done prior to and during the start up. the bike is solid state. Today I replaced a number of connections. Some corroded and some that just looked suspect. I had toyed with the idea of going through and restringing the entire bike, but, that would circumvent the process of elimination. And I could be creating a bigger problem. I think I'll wait until she is a reliable runner before attempting to upgrade all of the wiring.

[bighamms]

@ all... Ok, so I'm attempting to educate myself on motorcycle timing. I've read through quite a few old posts and think i understand it just enough to be dangerous. so, i've opened the cover on the right side of the bike and inspected all the connections. I replaced the oil pressure connection as it was broken (but still properly secured). All in all, things look like they are correct. I did snap off a few photos though, which i'll have to post individually. Please tell me if you see ANYTHING that looks out of place.

[IMG]file:///C:/Users/rsnead/Desktop/coffee/IMG_0781.JPG[/IMG][IMG]file:///C:/Users/rsnead/Desktop/coffee/IMG_0782.JPG[/IMG]
So when i rotate the crankshaft by hand clockwise and bring the bike to TDC on either/both cylinders, my markings on the trigger plate seem to be exactly where they should be. My question is, are the little black spring-loaded arms (sorry, not sure what the technical name is) suppose to move outward as I slowly turn the crankshaft by hand. Mine don't.

[spyug]

Off the top of my head I also think its timing related but I have also experienced difficulty in getting rebuilt carbs to work correctly. Before I condemn the timing totally I'm wondering if we can really prove that the carbs are shooting gas. With enricher full on a solid few minutes of cranking should soak the plugs which will tell us that they are working.

What I'd like to suggest is to hook up a car or boat battery in series to the bike battery. The bike battery should be fully charged. The auxillary battery will provide more cranking amps as you noticed already that cranking runs the battery down too quickly. You might even have an issue with the battery even though it may be brand new. It may not be providing sufficient voltage to both crank and fire. Can you confirm your full resting voltage and how quickly the voltage drops as you crank. I've found many occasions with batteries showing 12 to 12.5 volts that will not fire the bike. Cranks away but not fire.

With your IV gas bottle in place and batteries hooked crank away for at least 2to 3 minutes. If you see any smoke anywhere other than out the exhaust pipe or feel the bike battery is super hot.....stop immediately.

After cranking pull the plugs. They should be sopping wet. If not, you are not getting gas.

With my Kat project bike, my rebuilt carbs wouldn't shoot fuel and on the suggestion of a member I covered each carb mouth with cling film and poked a small hole in the center. Cranked again with the extra battery and in a few seconds it fired and ran. You could try that too.

If you do confirm gas then its got to be timing as suggested. I will need to read up on your engine's timing setup to see how we should test it. I'll try and do that this weekend.

In the meanwhile, please make sure that you really are getting gas into the cylinders. Not just the smell of gas on the plug but real wetness.

Please let me know what you find then we can move to the next step.

We'll get it figured so no reason yet to go the "insurance" route

Cheers,
Spyug