Ignition Issues

hi everyone. nice website and forum. i really like it (as web designer).

her is the reason why im writing and looking for some ideas. i rebuilt a 1981 kz750 4cyl and the bike always had issues, especially when warm or hot running very bad including backfire etc. i checked the carbs a million times and i can rule that out. they aren't perfect but clean and running. so i expected it to be the coils because the problems got worst and worst by day until last week it wouldn't even run anymore. it would run but you could here there was almost no detonation and once in a while it would detonate a cylinder running extremely rough. so i just installed the new coils and it turned on right away but as soon i drive it it just runs like crap. its stumbling trying to run but then you can feel and hear it have no right ignition or no correct detonation. almost like running out of fuel or having no spark or low spark. since its not the coils, what else could it be? it runs ok in idle, not great but it stays running. how about the igniter? i mean there isn't much else it could be besides bad cable right?

Could be a vacuum leak in the carb boots, with bike running at lowest idle, spray carb boots with carb cleaner and see if RPMs change
Pete

timing maybe. i painted parts and including the points cover

Clean all of the wiring harness grounds(most are BLACK with YELLOW stripe, and the main one from the battery Negative(-) post to an engine mounting bolt. Taking a M^ X ! tap to t he frame grounds, may remove the rust and paint enough for better operation.

that's exactly what i have planned for tomorrow morning. for me it feels like the timing is totally off but i would understand how that could change and it gets worst the warmer it gets

how can i adjust the timing here? i cant seem to see any markings on the plate outside.

element303 wrote: how can i adjust the timing here? i cant seem to see any markings on the plate outside.

I posted the Dyna S testing and installation in the file base. Make sure you disassemble, clean and lube the advancing mechanism behind that plate. I use heavy duty silicone spray because it goes on wet dries and does not collect dirt.
If you have a manual I would suggest running through ALL of the routine maintenance.

Good luck

thank you. would you be so nice and send me the link? im on the phone right now.

From looking at the plate in the picture, the screws on the slotted holes need to be loosened, to move the plate to advance, or retard the timing. You'll need a timing light to do this correctly. But remove them to get to the mechanical timing advancer. It should snap back when twisted(engine off). If not, you'll need to clean and lube it before timing the engine.

i think thats exactly the problem. it feels to me like its stuck and because of that the timing is totally off. is seem to detonate either way too early or too late but for me it feels like its too early. once in a while a cylinder detonated right but most of them are off. pretty sure its dirty, rusty, stuck. it got to be that. i will check that and all the ground connections in the morning.

i just got it open, and it seems pretty much clean and the parts are moving too. its not stuck. does this look like ok condition? also, the lose cable in the bottom, is that ground and where is that supposed to go?

element303 wrote: i just got it open, and it seems pretty much clean and the parts are moving too. its not stuck. does this look like ok condition? also, the lose cable in the bottom, is that ground and where is that supposed to go?

Cleanliness is next to Godliness! :lol: seriously, it could use a good cleaning and lubrication. This is where your ignition timing takes place and any troubles will show up as rough running.

The lose/un terminated wire looks like an oil pressure sensor. I would bet your oil light never comes on at all, unless the wire is accidentally or inadvertently grounded.

Just my guess! Good luck, Paul