1980 gs450L cdi questions

[Guest]

I am fixing up a 1980 gs450l which I learned to ride on back 25 years ago when it was owned by my father. He sold it for 1$ to my wife after she earned her motorcycle endorsement and after a year or so of use the motor died. The left side coil melted and even when I replace it, I was getting no spark on that side. I picked up a cdi box off of ebay and still would not run but I found the compression was low so I rebuilt the top end and fixed that problem but still won't fire off. I have spark on both sides but suspect the cdi box still. Any one have any thoughts on what I can do next? Has anyone ever tried on of these off of ebay http://www.ebay.com/itm/CDI-ECU-Suzu...25.m3641.l6368

[bikemtn]

Here is an older thread on the igniter unit. Basscliff has links to some tests.

http://www.thegsresources.com/_forum/showthread.php?164239-How-to-diagnose-the-CDI/page3

[uspsamaster]

Thank you for your reply, I will look into that some more. Can anyone tell me if the gs 450 has a wasted spark ignition? The reason I ask is mine, when cranking shows no sign of life and then a big back fire through the pipe. If it is also firing on the exhaust stroke that would explain it and it is less bad for my diagnosing. If not then could I have my timing off 180 degrees?

[tom203]

Since the trigger for the each ignition coil is on crank, the spark plug fires twice- once on the power stroke and then uselessly during exhaust stroke. If you are confident that you have spark at plugs, and since you had top end apart, suspect a camshaft timing problem. Do you understand how the numbers stamped on camshafts relate to crankshaft TDC?

[uspsamaster]

Yes the valve timing is correct (just in case someone looking sees the diagram posted it appears to be for the gs400 or 425 as the 450 is 18 pins not the shown 20) It also started backfiring through the pipe before I did the top end but with the replacement igniter I don't know if that is relevant but with the old igniter it would run just not on both cylinders (one side of the igniter produced no spark) Thank you for your continued help.

[tom203]

Make sure you have good spark at both plugs during cranking. Used ignitors can be iffy. So 18 pins, like in this pic?image.jpg

[uspsamaster]

I got it running last night. It turned out to be a wiring problem. Thank you for your time. Your help sent me in the right direction and saved me from buying expensive parts I didn't need.

[bikemtn]

I got it running last night. It turned out to be a wiring problem. Thank you for your time. Your help sent me in the right direction and saved me from buying expensive parts I didn't need.

Awesome news!!