Can't get het to start

[WBD]

Well, I just got my 78 GS550 and it has about 12,000mi on it. It was running great before it was last shut off. It sat for a year and now I can't get it started. I wasn't getting spark so I work on the rusty magneto (I think that's right) and now have spark. It still turns over but wont start. I pulled the carbs to clean them figuring it was gunked up. It wasn't. Gas is getting to the carbs and every now and then I get a backfire. I'm new to all this and kinda baffled. Any help is appreciated.

[DimitriT]

How's the battery? It may have enough juice to turn it over but not enough to get spark. Try a freshly charged battery and if that doesn't do it, it must be fuel (carbs) related.

[madjack57754]

Remember that you need 3 things to make it run, fuel, air, and spark. Start by eliminating one Pull the air filter. Look inside the airbox to see if there is an obstruction. Nothing, then go on to fuel. I don't know if this bike has a vacume fuel petcock, so check the petcock position. Use carb cleaner to give the carbs a healthy shot through the airbox. (DON'T use starting fluid. That stuff will creat more problems than you can imagine))With a good battery, Crank it over. If you have spark, it should pop. This might take a couple of tries. If there is still nothing, Move onto electrical. Possible it's grounding out. Check the kill switch. It's usually something small that creates the biggest headache.
If none of this works. Get back to us at the forum, and we'll go on from there. Jack

[49er]

You said that you worked on the rusty magneto and now you have spark.
I presume that it is the points that you are referring to.
When you worked on them did you unlock the backing plate. If you did and it moved, it's possible that you have lost the correct ignition timing. Also if the points gap is too great this will have an effect on the timing.
Was the bike left out in the weather over the year's layoff. It's unusual for points to rust badly unless water has been leaking directly onto them through a bad sealing cover gasket.
The backfire you mention is an indicator that your timing is wrong, or your battery is not fully charged.

[mark]

Check and see if gas is getting to the plugs. They should be wet if its getting gas. Also make sure when you use the choke that you do NOT open the throttle.

[Steve]

"I pulled the carbs to clean them figuring it was gunked up. It wasn't. Gas is getting to the carbs and every now and then I get a backfire."

Just because gas is getting TO the carbs does not mean it's getting THROUGH the carbs. There are lots of little holes and passages that are easily clogged by letting the bike sit (especially for a year), and that is what needs to be cleaned out. There is a good series on cleaning the carbs in the garage section of this site.


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[WBD]

Thanks So Much

Thanks all. What a great forum. Post a question before going home from work and when I get back all sorts of help. The battery is brand new and fully charged so that shouldn't be the issue. I did move the plate when I was cleaning the points so that may be a big issue, I'll check the manual for timing solutions. I also was not aware of all the little jets in the carbs. I was comparing mine to a friends carbs whose were really gunked up and mine looked really clean. I also didn't think to check the air. Thanks for all the help=D> . This is my first bike and my first adventure into getting one started.