Resurrecting a gs550. Help!

[ameen]

I have had a 1982 GS550 that i have been working on and off with for awhile now. I ended up rebuilding the top end and added a dyna ignition (ignitor went bad). Now i cannot get the damn thing to run.

I know i have a spark and the starter motor works, but i get nothing. I would figure that with the pistons pumping and a spark i should hear an attempt at firing when using starter fluid even if my carbs are not set right and my timing is off. Unfortunately i get nothing at all and at this point I'm not sure where to look next.

The bike has been sitting for about a year since i rebuilt the engine and i would really like to get it running for this riding season. Any help is greatly appreciated!

[mlinder]

How do you know you have spark?
And, if the timing is way off, even if you have spark, you may get nothing. Also, if your battery dips below about 10v while pressing the starter button, you may not actually be getting spark, though the starter motor will still be turning.
Also, how are you introducing starting fluid to the system?

There are too many variables here to make more than wild speculations as to why your bike won't fire.

[Nessism]

First thing I'd do is double check your cam timing.

Next is to make sure the carbs are 100% clean, new O-rings installed, new O-rings on the intake boots, airbox installed, air filter installed, and throw the ether in the garbage (actually, don't since it's explosive...but I trust you get the idea).

[Adler]

Just how sure are you that you have a good spark? Is it a nice fat blue spark?

If you do have spark the only other things I can thing of is compression and timing.

EDIT: wow... too late on two counts...

[Adler]

First thing I'd do is double check your cam timing.

Next is to make sure the carbs are 100% clean, new O-rings installed, new O-rings on the intake boots, airbox installed, air filter installed, and throw the ether in the garbage (actually, don't since it's explosive...but I trust you get the idea).

Why? I hear this a lot but I find it to be an invaluable diagnostic tool when used carefully.

[ameen]

I tested the spark my removing a plug ans holding it against the block. The spark is nice and blue.

right now, i have the air filter off and i am spraying the ether into the air box. I was using it to try take the carbs out of the equation to get this thing to fire.

As far as cam timing, i was pretty careful when i set it but i will check it again. I dont have a compression tester at the moment but using the thumb method, it seems OK.

The electrical timing i did following the directions supplied with the dyna ignition for static timing.

I know any one of these thing could cause the engine to either not run well if off by a bit, but i am perplexed my i get absolutely no combustion. Fuel + air + spark usually should equal at least a small bang. maybe Im too optimistic lol

[spyug]

It must be the season of 550s as I just picked up an 83E that I'm starting in on too.

Now if you have spark and the engine turns over then you must be missing gas and or your spark is not strong enough. I had exactly this situation with my Katana project last year. The carbs were rebuilt several times, the petcock worked properly, it had a good battery, I could test for spark but could not get it to go. there is a long rambling thread on it in the archives.

After all the fussing and farting it turned out that a)the carbs were not working correctly and b) the good battery was not strong enough to both turn the engine and produce the spark.

Once I got the carbs to run right and added a deep cycle marine battery to help cranking it fired right up. Once it had run for a bit it would then start easily on its own battery.

I think I would first try and confirm that you are getting lots of gas and would ad a booster battery as you may need to crank it a bit for the first time or two. In my experience I find that if the bike's battery drops under 12.4 volts it sometimes will not crank and fire. It will continue to crank way down until about 9 volts but you won't get spark too.

Another thing you may consider is doing the coil relay modification as we find that due to the bike's old wiring and connectors, the coils may not be getting full voltage to begin with. If you do a voltage drop test on that circuit you may find the battery could be at 12. whatever volts but at the coils the voltage has dropped to 11. something volts or less. This is fairly common it seems and the relay mod sorts this out.

The issue of fixing hard starting is not complete until we touch on valve adjustments. If you don't know the history it might be worth checking the valve adjustment as tight valves can make it damn near impossible to fire. While it may not be the sole reason, it would contribute to the problems.

Good luck and let us know what you find out.

Cheers,
spyug

[cowboyup3371]

In addition to everything else, verify your fuses are good.

[Nessism]

Cams could be 180 degrees out.

Set 1-4 T mark on the crank

1 mark on exhaust cam should be pointing parallel to the top of the head

The notches in the cams should be pointing at each other.

Count the cam chain pins between the 2 and 3 marks on the cam sprockets and compare to the service manual.

Ether is dangerous and only has value for lazy people that don't verify the basics before trying to fire up the bike. Do the job right: get the carbs right, install the airbox, etc, before thumbing the starter. There is NO good reason to use ether.

[ameen]

Fuses are good, and i actually jumping the bike from the car, so i know there is enough power at the battery side.

On another note, at some point during testing, my starter button broke off. So i tried shorting the two big terminals on the starter relay and it seems to work.

Is it possible for the spark to look good (while cranking) but still not be hot enough?

[mike_of_bbg]

Are you sure your coils are wired to the correct Dyna leads? Fat spark means nothing if it's not at the right time.

[Nessism]

The issue of fixing hard starting is not complete until we touch on valve adjustments. If you don't know the history it might be worth checking the valve adjustment as tight valves can make it damn near impossible to fire. While it may not be the sole reason, it would contribute to the problems.

Good luck and let us know what you find out.

Cheers,
spyug

"Rebuilding" the top end without checking valve adjustment results in automatic defrocking of your Man card. Don't go there.

[ameen]

Cams could be 180 degrees out.

Set 1-4 T mark on the crank

1 mark on exhaust cam should be pointing parallel to the top of the head

The notches in the cams should be pointing at each other.

Count the cam chain pins between the 2 and 3 marks on the cam sprockets and compare to the service manual.

Ether is dangerous and only has value for lazy people that don't verify the basics before trying to fire up the bike. Do the job right: get the carbs right, install the airbox, etc, before thumbing the starter. There is NO good reason to use ether.

Ill check the cams tonight.

On another note, I forgot how awesome this forum is. You guy are great, thanks!

[cowboyup3371]

Fuses are good, and i actually jumping the bike from the car, so i know there is enough power at the battery side.

On another note, at some point during testing, my starter button broke off. So i tried shorting the two big terminals on the starter relay and it seems to work.

Is it possible for the spark to look good (while cranking) but still not be hot enough?

Please reassure us the car was OFF when you jumped the bike with it?

[ameen]

Are you sure your coils are wired to the correct Dyna leads? Fat spark means nothing if it's not at the right time.

Ill check that tonight too. Tried switching some of the leads once to see if i was just retarded and got them backwards and it still did not work.