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View Full Version : GN250 electrical timing issue



lukecleland
12th June 2014, 17:24
Hi guys, my first post here - I have a 1985 GN250 that has stopped working, turns over but won't fire. It has good compression, fuel and spark but won't even pop. Here's a bit of background

Some months ago I changed out the clutch. Instead of dropping the oil I lay the bike on its side and swapped out the plates, probably took an hour. Job was all done and I got the bike started back up again and everything was sweet until about 30 mins into the ride when it started itermittently losing power. I thought it was the battery so I put it on charge (without disconnecting the terminals) and tried it again the next day. Still not turning over and no power. It was then that I realised that the earthing wire connected to the clutch plate had come loose so that the whole time it was charging it wasn't earthed. Since then, although the battery is fine and all the electrics (horn, starter, headlights, good spark) are fine it hasn't popped at all no matter what I try. I have replaced the CDI with a brand new unit but it hasn't affected a thing. I have cleaned out the carb 3 times and pretty sure that's not it as when I pull out the spark plug i can smell the petrol. Another thing I should mention is that I've even sprayed butane into the intake without the carbs connected which always usually fired in the past. It's almost as if the timing of the spark is on the opposite end of the intake/exhaust cycle. Could it be that the sparkplug isn't working when it's installed, because that's what it sounds like - although when I plug it out and turn it over it sparks cleary.
It's so frusting as you can imagine. I've tried hillstarting for a full mintue at a time with no pops at all.

I can't for the life of me work out what the problem is. I even took it to a mechanic and after inspection he didn't want to have anything to do with it. Please help if you can I'm at the end of my tether!

Cheers

Akzle
12th June 2014, 17:57
youre going to want a new sparkplug champ.

Akzle
12th June 2014, 18:02
okay, read your whole post now.
You should not have an old shitheap bike.
Im picking duc to massage your prostate on this one.

Drew
12th June 2014, 19:13
Sounds odd.

Drain the oil, take off the stator cover, and check to see if the ignition pickup and flywheel are ok. My brother has a GN and the key sheered off between the crank and flywheel. Timing goes right out the window once that happens.

lukecleland
30th October 2014, 18:27
Drew, I completely forgot to thank you all those months ago - I took off the flywheel after a long wait for the puller and the key had sheered clean off. You were right on the money. Cheers mate!

Drew
31st October 2014, 16:11
No trouble. I hope you lapped (fancy term for putting some cutting paste on the surfaces and rubbing them together) the surfaces and used loctite on that bad boy. Seems to be a common fault.