Narrowing down the problems to a broken bike

[Ratzo]

Kerry's great. Always helpful and consise. Kudos!!

[ViD381]

[Kerry]

Thanks guys - that's all the payback I need.  Well, that and a SOLUTION to Timothy's problem.  My pride's at stake!

Just so you know, I won't be back on until LATE tomorrow night, or sometime Monday morning.

[ViD381]

[Kerry]

I know I said I wouldn't be back on tonight, but "just one more"....

Carbs are complex things.  Your problem may turn out to be fuel-related in the end, but we're so close now - let's finish the electrical side of things.

As I wrote in the "old" threads ... the whole time I was trying to diagnose my problem I got (what I thought was) a good spark from both plugs.  When I finally found that the Black/blue wire connection was bad, I was floored!  That wire is common to both of the signal generator circuits, which should have meant that NO signals were getting through to the ignition coils.  How was I getting a spark at all?

I don't know.  But when I fixed that one connection ... VROOM!

My point? Getting a spark doesn't necessarily equal getting a GOOD spark or a CORRECTLY-TIMED spark.  Let's work this through to the end.

[ViD381]

[ViD381]

[Kerry]

OK.  You don't want to take readings on wires coming from the "black box" - Suzuki hasn't published any resistance or other values that you could use to test that unit.  And it's not serviceable - if it's defective (which there's apparently no way to determine  :guns: ) you have to replace it.

But never mind that "black box".  On to the rest of your post.

If you took the other readings where I think you did, you're DONE!  Just to make sure, you said

I also tested the female end (the ones leading away from the black box)

These 3 wires go to the black 4-wire connector, right?  The one that was corroded on my bike, and that I replaced with the 4 pink quick-connectors?

If we're talking about the same wires, then you've just tested your signal generator coils and found acceptable resistance values; 370 is definitely between 240 and 420.

Whew!  

Unfortunately, since your signal generator coil circuits (and ignition coils) appear to be OK, we still don't know what's causing the bike to act up.  Time to start over and think it through some more.....  :x

[ViD381]

Okay the clear three wire one checked out okay. The black four wire one didn't check out okay. All the wires except the green and yellow one had a reading of 350-380. I know that the green/yellow one goes down to the right side of the bike where the Suzuki faceplate is. When I unscrewed that plate the wire was the only one that had a screw that allowed me to remove the wire. All the other wires were firmly soldered in place. (If this is indeed the bad wire, and I was able to unscrew it while the bike was on with no problem) then how do I go about finding the bad link? The wire is in a black tube throughout the entire bike.

-Timothy

[Kerry]

Since you got the correct readings at the 3-wire connector, you know that the rest of the connections down through the 4-wire connector and to the signal generator coils are good (for those 3 wires).

If you look back at the wiring diagram, you'll see that the green-yellow wire goes to the Oil pressure switch, and has nothing to do with the signal generator coils.  Suzuki just found it convenient to run that wire through the same 4-wire connector as the others.

Like I said - you're done with the electrical testing.  Time to look elsewhere.  

[ViD381]

[Kerry]

You need to turn the screw between the carbs.  It's part #39 in this BikeBandit diagram:

http://www.bikebandit.com/partsbandit/showschematic.asp?dept_id=723027

[Von Vester]

Is this a private troubleshooting session or can anybody join?

A very frequent cause of spark plug distress is cracked spark plug leads, particularly on older bikes. If an old motorcycle sits outside for long periods of time the sun light falling on one side of the bike will cause 'weather checking' on that lead.

Its easy to test if this is your problem. Start your motorcycle at night in a the darkest place you can find (cover the head light or disable it) and then look for little blue sparks jumping from the ignition lead to the motorcycle frame or engine block. As you seem to enjoy the little rise you get from the spark voltage you can also use your had to find electical 'leaks' in the spark plug leads.

By the way the 'spark plug leads' are the thick black wires going from the coil to the spark plug. Just another idea.

[Kerry]

Welcome to the party!  Feel free!

Thanks for the input.

[ViD381]

[Von Vester]

I had an identical problem when I bought my used '93' GS. The bike ran so rich at low throttle that it was hard to get it off of a standing stop without a lot of throttle milking. One cylinder kept carbon fouling its plug.

When I disassembled the carburetor on the offending cylinder I discovered that the spring seat (called a 'ring' in the parts manual) for the jet needle was missing. Nothing holds the 'ring' in place except the spring so that means that the 'ring' falls on the floor as soon as the carb is dissassembled. When I installed a new 'ring' the worked flawlessly ever-after. That was 3500 miles and 4 months ago.

If the 'ring' is missing the spring cannot hold the jet needle in place so that the needle rises during low power settings allowing more fuel into the cylinder. At higher power settings the jet needle is pulled up by the diaphram so that the absence of the 'ring' is not as noticable.

The Suzuki p/n for the 'ring' is 481809-001, however, I wuld advise disassembling the carburetor and checking before you order. They are about $3.00 each. Hope this helps.

[ViD381]

I will have to check for that "ring." Since I don't know what it looks like is there anyway you would be able to give a picture of it? Maybe this link will have the part on it.  If it's what i'm thinking it is, than it's part #21 on bikebandit. This "ring" is what holds part #21 on the float correct? If it's not part #21 will you be able to tell me the part number so I can give a looksee on my next visit to carb-land.

http://www.bikebandit.com/partsbandit/showschematic.asp?dept_id=723027

The dealership will more than likely change me about $9 for it. They're not that nice when it comes to prices.  

You Rock!!

Thanks for the help

-Timothy

[Von Vester]

You are looking too deep into the carburetor. To access the 'ring' I am speaking of (#3 on the drawing) all you need to do is remove the gas tank, and remove the top cover (6) from the carburetor.

Lift out the spring (5) and look on top of the the jet needle (18). The 'ring' (3) is a small plastic collar that sits on top of a clip (4) around the jet needle( 18). The 'ring' (3) is only held in by the spring (5) so that it may stick to the spring and come out with it. It is very very easy to loose. Be careful.

The 'ring' (3) is the spring seat that provides the pressure point for the spring (5) to push down on the jet needle (18). Without it the spring (5) passes uselessly around the jet needle (18) and your mixture control goes to H*ll.

If this is not your problem make sure you don't make it a problem. Be sure the 'ring' (3) is properly installed when you reassemble the carburetor.

[Von Vester]

I don't know why but I was trying to type the number 'eighteen' to reference the jet needle, but it came out as a 1 and a smilie face.

[Kerry]

I don't know why but I was trying to type the number 'eighteen' to reference the jet needle, but it came out as a 1 and a smilie face.

The same thing happens to me when I number list items using a digit followed by a right paren.  The system interprets

Code Select Expand

8)
as a goggle-eyed smiley face:

Hey, check it out!  Right below the text edit box in the Reply screen is a checkbox labeled "Disable Smilies in this post".  I learn something new every day!