having an engine start up trouble.

[cyrusyn]

Hi,

1996 Suzuki GSF600 Bandit

This morning my bike wouldn't rev up in the 1st gear and kept sputtering when I applied throttle. However the engine revved freely when in neutral gear.
Now this evening when I tried to start it again, the bike didn't fire up. It only cranks and doesn't fire up.

Need your advice.

Thanks!

[Aussie Steve]

Check out the safety cut out switch at the clutch and at the side stand if fitted. Long shot but it sounds like something stupid like one of those if it will rev in neutral OK.

Good luck.

[cyrusyn]

If the sidestand safe switch and the clutch switch are not working properly, wouldn't the engine n starter motor not crank when I press the engine start switch?

[Easy Rider]

Originally Posted by cyrusyn

If the sidestand safe switch and the clutch switch are not working properly, wouldn't the engine n starter motor not crank when I press the engine start switch?

That's probably true.
Sounds like a fuel delivery problem.....or water, etc. in the gas.
Are you SURE you have gas (look, don't assume)?

[cyrusyn]

I do have gas. I saw it inside the fuel tank.

[Easy Rider]

Originally Posted by cyrusyn

I do have gas. I saw it inside the fuel tank.

No time for a detailed reply now.
Your situation is not much different than a hunderd (or so) others who's bike won't start.
Do a search for "start" or "won't start". There should be a TON of hits.
It sounds like a fuel problem to me but check the spark first.....since that's easiest.

Good luck.
More later if needed.

[Aussie Steve]

Probably correct but intermittant faults can be a devil of a job to trace...and can cause all sorts of mysifying problems. Easiest thing to do to check ER's idea is to pull the plugs and see if 1: they are wet or dry. And 2: try a spark test with each plug grounded to the cylinders. This will possibly be only a symptom and not the real fault but it is a starting point. From there you can track what is causing the loss of spark or fuel delivery. One thing many are not aware of is on multi's even if it is only one pot that is not firing often the rest refuse to go too...sort of out in sympathy I guess.

Good luck and let us know what you find.

[cyrusyn]

Thanks a lot for your advices, guys.

I checked the spark plugs.

#1 had very very small spark, yellowish
#2,3 had bigger but yellow, white-ish sparks
#4 had white-ish blue sparks.

So I changed all four spark plugs. With new spark plugs, the sparks from the number 2 and 3 are weak while 1 and 4 are strong. All of the 4 spark plugs are producing bright yellowish sparks.

And engine cranks but doesn't fire up although I hear it coughing.

So should I check the ignition coil or CDI for 2 and 3 or move on to troubleshooting on fuel?

[Easy Rider]

Originally Posted by cyrusyn

With new spark plugs, the sparks from the number 2 and 3 are weak while 1 and 4 are strong. All of the 4 spark plugs are producing bright yellowish sparks.

Those two statements don't seem to match....to me at least.

Assuming that 2 & 3 share a coil or other components, I'd say that something is amiss there......but probably not enough to keep it from starting.

I think I'd give it a shot of ether (starting fluid). If it springs to life with that, then I'd say fuel is next.......and you can come back to the weak spark(s) later.

Or continue and fix the weak spark first. Murphy says: Which ever you choose to do next, it will probably turn out to be the wrong choice.

[cyrusyn]

Originally Posted by Easy Rider

Assuming that 2 & 3 share a coil or other components, I'd say that something is amiss there......but probably not enough to keep it from starting.

Thanks!

2 n 3 comes from same coil while 1 n 4 comes from another coil.

What is this ether (starting fluid)? Will this work on a carburated engine without damaging it?

[Blade]

Yes, it will not hurt it just to get it started. But from your discription, almost sound like a coil is going bad or not getting enough juice.

[cyrusyn]

will ether work if my sparks are weak to ignite anything in the cylinder?
If this is a weak spark problem, ether won't burn inside the cylinder and is no use... no?

Where can I get this can of ether in San Francisco, California?

[Easy Rider]

Originally Posted by cyrusyn

will ether work if my sparks are weak to ignite anything in the cylinder?
If this is a weak spark problem, ether won't burn inside the cylinder and is no use... no?

Where can I get this can of ether in San Francisco, California?

When it comes to a complicated piece of equipment like an engine, nothing is easy.

Starting Fluid can be had at any auto parts store.....including probably the auto department at places like WalMart. It is HIGHLY volitile and ignites much easier than gasoline. Used improperly, it is DANGEROUS so read the directions....carefully. Have the battery fully charged before hand. NOT to be used along with jumper cables as sparks may cause vapors to ignite.

It is good stuff to aid in troubleshooting BUT because it burns easier than gas, it can mask a weak electrical system. It will sometimes fire with a weak spark when normal gas won't.

Sometimes using it to actually get the bike to fire for a few revs. will suck gas into places in the carb. that are slightly restricted and clear them out a bit. That works best if there is some carb. cleaner already mixed with the gas in the bowls.

Just went back and reviewed the posts. The way you described the original failure, it REALLY sounds like a fuel delivery problem. Have you opened the drains yet to be SURE you have gas flowing to the carb. bowls? If not, that would be my next thing to do........along with putting the petcock to RES or PRI just to be sure you have ENOUGH gas in the tank.

[cyrusyn]

Originally Posted by Easy Rider

Have you opened the drains yet to be SURE you have gas flowing to the carb. bowls? If not, that would be my next thing to do........along with putting the petcock to RES or PRI just to be sure you have ENOUGH gas in the tank.

When you said drain, did you mean the petcock? If not, how do I open the drain?

Thanks so much for your advices.

[cyrusyn]

I just tried coil swap and tried ether.
The 2 and 3 coils produced consistent yellow sparks. And with ether, the engine ran for 2-3 minutes with the choke lever fully down.

Now, I have to look into the fuel system. What do you recommand me to take a look into first?

[Aussie Steve]

Ok one problem at a time.

To drain the float bowels there should be a small screw near a nipple at the base of each carb. You undo the screw after first fitting a short lenght of tube to the nipple and running it into a container.

Once you have fuel flowing...petcock on prime... you know the carbs are getting fuel. Also any crud build up is removed with the flowing gas....in theory anyway.

I would strongly suspect an electrical fault seeing as how you only have what appears to be weak sparks. A good ignition system will produce big fat bluish white sparks at all plugs. I would check the condition and connection of the battery and work back to the coils, HT cables, and plug caps. Check any wiring and relays in the ignition circuits.

Good luck

[cyrusyn]

thanks a lot for the advice.
My petcock only have on, off, and res.
Which one of those three is prime?

[Easy Rider]

Originally Posted by Aussie Steve

I would strongly suspect an electrical fault seeing as how you only have what appears to be weak sparks.

Yes but you really think that is causing it not to run ?? Considering that he can get it to fire up....and apparently for more than a few seconds....with starting ether ??

Originally Posted by cyrusyn

My petcock only have on, off, and res.
Which one of those three is prime?

Oops, older bike. Use ON. Fuel should flow freely in the ON and RES positions. Does it have an inline fuel filter? If so, change it. If not, you probably want to add one after you get this problem figured out.

At this point, I think you need a complete drain and flush of the tank, lines and carb bowl. There might also be a little bowl below the petcock with a screen in it to clean. After that comes carb. cleaner in the gas.
More details later if you get that far.

When messing with the fuel lines etc., you should always start out with the petcock OFF, then remove a line, open a drain, (whatever) and then slowly turn it to ON.......so as to prevent fuel spewing all over while you take things apart. Some fuel will leak out anyway; have some rags handy and be sure you have good ventilation and NO SPARKS.

Good luck. Considering your level of experience with engines, have you considered taking it to a shop?

[cyrusyn]

Easyrider,
Thanks a lot for your advice.

>Considering your level of experience with engines, have you considered taking it to a shop?
I can't afford a shop service and I think shops around San Francisco all stinks any way. I used to play with KA24E and KA24DE engines on Nissan 240sx and always wanted to play with carburators so I think I should do this myself anyway... The sight of 240sx engines or old BMW engines fitted with carburators were always wonder to me.

This bike (which was salvaged) has a history of fuel tank swap due to long storage and rust built up inside the fuel tank. So I will try cleaning the fuel system clean as you recommanded. Do you think I should use a can of Goumont fuel system clean?

>Oops, older bike. Use ON.
Bike is 96 but the people who sold me this bike changed the petcock after realizing that it was leaking.

And all this began to happen the day after my bike was knocked over. I don't know how this would play into this problem.

[Easy Rider]

Originally Posted by cyrusyn

And all this began to happen the day after my bike was knocked over. I don't know how this would play into this problem.

That's not too hard to figure. Rusty tank got thumped. Some rust came loose. It is now plugging up something...in or prior to the carb.

Re-read previous post.
Can't give much more advice by remote control.
Good luck!