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Now I need help on my gs450


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#1 The Butcher Shop

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Posted 10 March 2009 - 12:08 AM

Well, shit was going great on this build. I have ran into a problem. 1981 suzuki gs450, electronic ign, dual cyl, dual coil. I did a simplified harness on this bike. Had the plugs laying on the head, check for spark, had spark on both sides. Go to start the bike and it wont run. Has 150-160 lbs of compression on both sides, has spark so I rip off the carbs to re-clean em. Still nothing. I check spark again and see that the left side plug has a constant spark to it (not flashing like normal). I check my wires and see that I had the wires on that coil crossed. I swap em and have perfect spark. Put the plugs in, fires up and runs great for a couple secs. The bike then starts to run on only the right side. Pull the plugs, no spark on the left side again. I check the wiring-Good. switch plugs-plugs are good. Switch the wires with the two coils-both coils are good. Check the pick up coils- both are within the limit of ohms. Swap wires with pick up coils and test run-they test good. Check grounds-all have perfect continuity with the ground to the bat and engine. I sum it up to I fried the igniter box(cdi) when I had the wires crossed. Today I find another cdi. I wire it in and check for spark- have spark on both sides. I put the plugs in and start it up. Once again, runs great then I lost a cylinder. This time the right side took a crap on me. I pull the plugs and I have no spark on the right side now. I once again go through everything I mentioned above and all test and trouble shooting points towards the cdi. I put in a brand new, fully charged bat and it still does the same thing. Now after have a couple high balls and thinking about it and going over the schematics for the hundredth time, the only thing comes to mind is that I had a bat charger on the bat when I ran into this problem. With the new fully charged bat, I didnt use the charger, however this was after the second cdi crapped out. ------- I need input. ----- Thank you. Oh, the schematic isnt complicated at all. Trust me, I have compared the factory and my schematics over and over. I wish I could say the problem was I have it wired wrong, but they all are going where they need to be. It is prob something stupid and easy that Im not catching.
Put the blade to it!!! Don't be afraid, its only metal.

#2 CutNup

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Posted 11 March 2009 - 07:36 AM

since you built your new harness did you use slip on connectors of did you soilder the wires together?

#3 wally

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Posted 11 March 2009 - 08:40 AM

The kick and look for spark method sucks. Buy one of these:
Posted Image
Available at Harbor Freight, it'll set you back $2.00 and makes checking spark way easier. If you are getting spark, it has to be fuel (although could be timing, or valves not set right, etc., we'll keep it simple though). I would give it a shot of starting fluid, see if she wants to run. If she wants to start you know it's the carb(s) or intake leak, or something fuel related.
If you don't have a spark on both sides, check all your grounds first with a continuity tester. If all your grounds are cool, start checking all your connections.
The ol' process of elimination will get her runnin'.
Good luck and keep us posted.

Wally
no amount of planning will ever replace dumb luck.

#4 The Butcher Shop

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Posted 11 March 2009 - 01:48 PM

Well, This bike is getting the best of me. The cdi consist og the orange wire- power in and power to both coils. brown, green/w, and black/w- going to the pickup coils. black wire-ground. white-left coil. black/y-right coil. I have switched the reg/rec for good measure. I have gone through with the ohm meter checking ground. I have perfect ground throughout the bike with zero resistance. For signal wires I am running 18g wire and for power and ground I am running 14g wire. All connections have been made by making an X with the two wires and twisting the wire onto the other then with soider on them. I have swapped the cdis, one will only ignite the right side coil, and the other only ignites the left side. Once again, swapped coils, pickups, plugs, they all operate correctly. I will post a pic of the bike once I figure this out. It doesnt look that great with a vineyard of wires all over it. Any other help on this would be great. I would gladly buy another cdi to try that one, but two problems, cant find one around here, and I kinda think there is something wrong that is making the boxes to do this. It is just kinda weird that two boxes do the same thing but just opposite coils. Once again thanks. here is a pick of the bike when it was all mocked up. http://i295.photobuc...pg?t=1236797201
Put the blade to it!!! Don't be afraid, its only metal.