1 and 4 not firing

[motorbikemichael]

I have a 1978 Suzuki gs550L. I started with new plugs and drained the gas tank to start with fresh gas. It has alway been slow to warm up but was not firing on all chambers. 2 and 3 exhaust heated up so i knew it was running on those two only. I loosened the bowl of the first card and fuel started to seep out of it so it is getting fuel. I took the coil for 1 and 4 in to get checked and it is working. I can not get it to spark when grounding a plug outside of chamber even the firing cylinders wire does spark. I did get it running with 2 and 3 to 1200 rpm for a while and it seemed like it was coming to life but the exhaust for 1 and 4 never got hot to touch. My battery will need to be replaced but could that be part of the problem. I have not picked up any additional spark plugs in case those two were just bad or fouled.

 

[Spyderman]

check your points and condenser for 1&4 chances are that is where your problem is if your coil checked out ok
and yes the battery could be part of the problem but not the whole problem and so could the plug or the plug caps

 

[klr]

Check to be sure you're getting power to the coils and to each set of points. I had the same problem and found that the wire from my points to my coil had come unplugged where it joints over the carbs.

 

[tlepac]

I bet you that BassCliffs site has a manual for the 550 and you can check the ignition circuit. You could also switch the coils to be sure that the problem is really in the wiring up to the coils or in the points. Should be easy to track down with a multimeter.

Good luck

 

[BassCliff]

Greetings and Salutations!!

Greetings and Salutations!!

Hi motorbikemichael,

The left coil fires #1 and #4, the right coil fires #2 and #3. Points are split the same way but I would have to check the manual to be sure which is which.

Anyway, I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

The maintenance procedures in the "mega-welcome" are guaranteed to deliver you into GS nirvana, if you take no shortcuts. Remember, you're working with a 30+ year old machine.

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

 

[gs road racer]

Replace the plug caps first if any of the before mentioned doesn't help. wiring....power at the coils.... no power start checking backwards through wiring to the ignition plate look at points and condensor for that side. you can disconnect the condensor to check it just take the lead off it (removing it from the circuit) and see if you have spark Check coil for continuity to ground and through the plug wires... let us know how it went!

 

[motorbikemichael]

Great tips guys, thanks. I knew that my battery would need to be replaced but thought i could get some more use from it. It finally just died and would not take a charge. When i put in the new battery the bike fired up running on all 4. My 550 has alway been hard to start when it is cooler even with the choke. I will be using this site to try to fine correct it.