Starting problems on gs550

[EricWoods]

Hi everyone. Just a small post on my gs starting problems. Well i put in the new plugs, clutch cable and front brake switch. Got the clymer manual and decided to spend a few hours on saturday testing different things. Tested the signal generator and got correct resistance between wire pairs. one thing im not 100% sure on is the ignitor unit. I notice with the spark plug that the spark is not very strong but Im not sure if its correct. Just wondering could there be a prob with the ignitor that im not getting a strong enough spark? What i cant understand is that it wont start on the button , yeat if i push start it in first gear it starts? I imagine i need to take the carbs down and clean em but kinda hoping its something different!! Just wondering can anyone shine any light on this strange start problem. When I do get her started, if feels like im running on choke and the first quarter trottle makes the engine null then it revs correctly. Just for a split second it nulls. Also i noticed when I left the fuel tap in the prime position I had fuel over flowing from the air pipe on the air box. Took out air filter and there was petrol on the bottom of the air box? My heart is telling me carbs but the spark issue has me wondering! Do I need a new igniter? Is it not strong enough? Help!!!!!!!!!!!!!!!!!!!!!1
Eric In dublin Ireland

[nabrams]

Eric,

I'm assuming you've got a brand new, fully charged battery.
You've got multiple issues.
1. Non-sealing float needle valves - VERY common.
2. Weak ignition component (either ignitor or coil) - also VERY common.

Both of these have been discussed to death by me and others in this forum - do a search for remedies.
You'll also probably have to go through the "check-list" of verifications to work out all the kinks (compression check and valve clearance are often ignored).

[Bizcocho]

My good-running GS doesn't have a strong spark like cars I've worked on. I've been told that's the nature of the ignition. Don't know for sure.

[Ironriot]

Hi Eric what year is your GS? Is it pre '80? If so you could be having a problem with your points

[EricWoods]

Hi ironriot

Hiya . My gs is 1981T. I bought it here in Dublin, but apparently it was an american import. Taking Sunday off to strip it down. I guess the safest thing to do is to spend a day on the carbs and carb engine boots. At least elliminate that out of the equation. Got brand new petcock and battery in her. Its just riding like a dog at the moment. Ive noticed for example at 50 the engine is at 5000rpm, 60 at 6000rpm, 70 7000rpm and feels laboured. Still staring on a hard push but not on the button. Will do day on carbs but have no replacement o rings at hand but anxious to get it done so will have a stab without the o rings for the moment!!!!!!

[BassCliff]

Mr. EricWoods,

After leaving your petcock on "Prime" and finding fuel in the airbox, I would also be concerned about fuel in the crankcase oil too. The fuel makes its way through the #2 carb, down the cylinder and into the crankcase. Please check for gasoline in your oil before you ride again. If you suspect a bad petcock, the easiest thing to do is replace it and not worry about it again for another 20 years. Please keep us informed of your progress.

Thank you for your indulgence,

BassCliff
(Novice motorcycle mechanic, but I'm learning)

[EricWoods]

Hi Basscliff

I changed the petcock bout a week ago. It was after changing this that i noticed the petrol leaking out of the air box. Ive been searching comapnies that clean carbs online and found a company that does a comprehensive overhall for 380 dollars? does that sound good?. Im half handy with the tools and fancy having a go myself but with no replacement o rings am i waisting my time?
Eric In Dublin

[Nessism]

I changed the petcock bout a week ago. It was after changing this that i noticed the petrol leaking out of the air box. Ive been searching comapnies that clean carbs online and found a company that does a comprehensive overhall for 380 dollars? does that sound good?. Im half handy with the tools and fancy having a go myself but with no replacement o rings am i waisting my time?
Eric In Dublin

Just do the job yourself. Check the carb rebuild series we have on the site and have a go. If cycleorings.com will not ship you a set, order some rebuild kits off ebay - about $75 USD per set. It is not a hard job, just takes some time.

Good luck.

[nabrams]

$380 for a carb re-build?!?!!?????
You've got to be crazy to pay that.
I've bought complete running bikes for less than that!

[brveagle]

I'd first start with carb work. That's gonna be the reason why your bike is hard to start and not running right. Also change your oil.

[ironb12s]

Let's add to the fray, now, with checking connectors and grounds.

Get the carbs off, get the rebuild kits ordered, and whilst you wait for them to arrive, check the grounds on the bike, using an ohmmeter, from the frame and engine grounds back to the battery negative post. If you get more than 0.1 ohms, the contact points need to be thoroughly cleaned of any corrosion. Repeat for the Dielectric grease upon reassembly. Look over the connectors, you can check the ohms in them too (stick the probes in the backs of both sides), clean as needed. Report back results...

Carbs are your running problem, but the electrics are the starting problem.