Hoses, vacuum and otherwise.

[mattfrme]

Greatings all,

I have a 1979 XS1100SF (Special). This is the first bike I will have ridden in over 10 years

I bought it last fall from a guy who left it outside, uncovered for a couple of years. prior to that the bike was supposedly garaged.

The bike is actually in pretty decent shape. Very little rust, and well maintained. However, there has been this problem getting it to start.

The guy I bought it from mumbled something about "coils" through his drunken stupor. It did start, it even ran. I towed it home, with A LOT of effort it started sometimes. I changed the oil, filter, drained gas, filled with new. Then it would not start.

Ok, New battery, new plugs, tested coil, yep, up to spec. Was not sure what "big fat spark" was as opposed to "little flash", but coils measure ok on the multimeter...

Strip the carbs... Clean 3 times, finally got the broken pilot tip out, new parts, got the stupid thing in, what is this screw doing here... Carbs out, clean, re-inspect, reinstall (getting pretty good at this)

still no start, second hand starter from ebay, major improvement in crank, still no start. used coils (now I know what a "big fat spark" is), regap plugs, excellent crank, no start.

ok, are the hoses wrong?

Octopus is set up according to schematic (with filters installed). BUT, where does the vacuum connect? what are these?

more specifically:

1. On the #2 carb boot there is a nipple. what connects here?
2. On the back of the octopus is a nipple that points towards carb #1. what connects here?
3. There is a hose on the forward left top of the middle gear/transmission assembly, where does this connect?
4. On the back of the middlegear/trans assembly under the battery box is a hose. where does this go?
5. ON the intake/ airbox side of the carburator are 4 hoses. I realize 2 go to the petcocks, which 2, upper or lower. where does the other set go?

I know, get a manual, look on the Yamaha website. Thanks. I am waiting for the manual to arrive, and the parts pages do not show how the various parts inter connect, not much help for this instance.

I am sure this is an easy question, it is a matter of looking at your own bike, but with out it in front of me it looks like spaghetti.

Thanks in advance.

matthew

[mitch]

Carbs

OK the carb set up is in the maintenance section under carbs, it shows you how to plum up your carbs and octypus. The lage pipe is coming from the back of the tranny goes to your breather box, two lines from your carbs go to the octypus and two just slide into the back of the breather box to vent your carbs. The # 2 nipple is a vacumn line that goes to your octypus i think hope this is some help...................MITCH

[Ken Talbot]

Actually, the nipple on the #2 carb body supplies the vacuum needed for the vacuum advance assembly.

The nippple on the back of the octopus that points towards carb #1 can connect to any convenient nipple on one of the manifolds. It supplies vacuum to open the diaphragm in the octopus which lets the fuel flow to the carbs.

[mattfrme]

hoses part 2

Ok guys, I am getting confused, you seem to both be sayind different things...

Mitch says connect the octopus nipple to carb boot number 2,
Ken says Carb boot #2 is for the vacuum advance, plug the nipple into any other.

UGH.

there are 2 nipples on this boot. One is on the carb side, the other is on the engine side.

so I am plugging the octopus into the nipple on the carb side and the vacuum advance (which is I assume the hose from the front side of the engine case, sort of next to the shifter pedle) into the engine side? is this correct

Also, my carb has 4 hoses on the airbox side (separate from the octopus). They connect to a connector which lies between the individual carbs, two are between carb 1/2 2 are between carb 3/4.

So when the petcock diagram says to connect to carb, do they mean the top set or the bottom set. what do the opposing hoses connect to?

I am getting there, alot of back firing while cranking, but still no starting.

any ideas?

Matt

[Ken Talbot]

The fuel lines connect to the lower Ts between 1-2 and 3-4. The upper Ts are atmospheric vent lines that connect to nipples on the front, upper face of the airbox.

[CMA1]

And Matt,
The way you stated it in your post, you have the lines to carb 2 reversed.
The vacuum line from the left side engine cover (vacuum advance line) plugs onto the nipple of Carb 2....
the Octopus line plugs onto the intake manifold/collar nipple (engine side of carb2)

I hope that is clear, as mud...
Hope you are having more luck than I.
Happy Trails..

[mattfrme]

Gentlemen,

Your assistance has been great. I have hooked up the hoses per instructions. It still wont start, but the hoses go the right way.

occasionally it rumbles, but doesnt catch.

It doesnt seem to be getting gas at the spark plug. Float bowls fill up, you can see the gas moving through the filters, lots of back fire, no start.

wont even start with starter fluid sprayed into the airbox.

I am running out of ideas...

Matt

[TopCatGr58]

Hey there Matt,

I hate to ask, but are you familiar with the CHOKE/Fuel Enrichment lever that is on the left side of the bank of carbs? Is that pulled all the way out, there are usually 2 detent positions it will slide into, full out, halfway out, and then all the way in=no choke!

Pull the plugs and check them for fuel fouling! You may need to clean them! So, when you took the carbs back off, you found fuel in the bowls after previously emptying them, hence you say it's getting the fuel down to the bowls!? Try turning the petcocks to PRIME, this bypasss the Octy sends fuel straight to carbs without engine running or any need for vacuum to the Octy control valve!

Did you check the compression on the cylinders? When checking the Spark, are you letting it turn over several times and see if you are seeing repeated flashes of the spark from the coils?
T.C.

[Ken Talbot]

Okay, now it sounds like you've got the air/fuel part of the air/fuel/spark requirement met. You indicate the coils tested okay on a multimeter.

Try this: Pop all four plugs out, put them back into the plug boots, lay them against the head, and spin the motor over. Look for a regular spark from each plug.

[mattfrme]

Hello again,

Ok, I tried Ken's test, Interesting results. I am using stock coils from a known working mc. The primary wire reports 4-5 vac for both. However, when I put the plug on the engine block and crank, a little puff of white smoke comes out of the plug when it does spark (which is a generous term considering the size of the spark) it seems to originate further up inside the plug rather then at the top.

So perhaps new plugs.

I have also tested the resistance from the TCI to the primary lead, both sides show continuity, as does the ground.

I have replaced the rectifier, no change.

The question is this: Originally this mc had ACCEL coils connected to ground and orange/ Grey cable. The coils that are on it now (which are yamaha) connect in the same fashion. However, in the parts blow up picture, there is a resistor assembly adjacent to these coils. As There was not one here, I am plugging the cables in directly as the accel coils were.

Do I need this resistor? Is there a way to verify that the installation? would a short in the electrical system show up only when the bike is actually cranked? AND what would make a coil fail?

Both coils are identical. I am using the one connected to the orange cable to go to the 1st and 4th plugs, the grey cable connects to 2 and 3.

There does not seem to be a change regardless of how these are connected.

[TopCatGr58]

Originally posted by mattfrme
Hello again,

Ok, I tried Ken's test, Interesting results. I am using stock coils from a known working mc. The primary wire reports 4-5 vac for both.

The question is this: Originally this mc had ACCEL coils connected to ground and orange/ Grey cable. The coils that are on it now (which are yamaha) connect in the same fashion. However, in the parts blow up picture, there is a resistor assembly adjacent to these coils. As There was not one here, I am plugging the cables in directly as the accel coils were.

Do I need this resistor? .

Hey there Matt, well after deciphering what you said above, that the Primaries are only showing 4 to 5 Volts ?AC?, do you mean DC?, but anyways, that is a big part of your problem. The OEM setup uses a ballast resistor that is bypassed during startup to provide full 12v power to the coils for stronger starting spark, but after the engine starts, then the power to the primaries is run thru the resistor that drops it down to about 9V. The higher voltage ALL THE TIME without the resistor on the OEM's will cause them to run too hot, and fry them!!! With your Accel coils, you didn't need the resistor cause they were engineered to run on 12 volts all day, but if you're only getting 4 to 5 volts, you've got to do some cleaning of the power lines/connectors to find out where the voltage is dropping!!! Keep at it, and if you get the voltage back up to 12, put the Accels back on!!!! Good luck. HTH.
T.C.

[mattfrme]

Greetings all

Thanks again for all the help you have been providing.

Ok, lets see if I can clear this up. I have 2 sets of coils. One Accel which were on the mc when I got it, one Yamaha (from EBay) Seller swears they worked; I have no reason to doubt him. However...

The Coil FAQ listed elsewhere on this site, states that testing the coils is as follows:
1. On Primary connection, resistance should be 1.5 OHMS. I am getting an infinite level
2. On secondary connections, I should be getting 2.5 ohms. I get about 40 OHMS.

Seems dead to me. Correct?

So, replace the coils. I am a bit leery to do this as. Assuming that the coils Yamaha coils were good (the spark test showed good spark, and ohm test was not done), then why did they die?

This mc has done nothing but get cranked. It was never started on the Yamaha coils.

Further, as I know that the Accel coils started the bike last fall then died, my question is what would be killing the coils?

I have to admit that the MC battery is attached to a trickle charger. Would this cause a problem? Am I sending too much power down the line during crank?

BTW, with the key on and neg probe on neg and pos probe on orange/grey, ohm's show at 1.7 for both. This is with key on and key off. Does this mean that I am getting correct power to coils?

I have not really played with the electrical system other then as follows:
replaced broken positive cable to rear right blinker. It works fine now.
Replaced starter relay with new Yamaha OEM
replaced pos and neg battery cable.

All connections have been cleaned; I have at least 2 of each component, which have all been swapped out.

The wiring harness has no significant blemishes, cuts, or obvious problems
The starter was replaced.

Battery was replaced last fall; electrolyte levels are all within range

so any ideas where to begin?

Also, how do you test voltage at the coil? (How do I check to make sure it is 12 vdc?)

Back to scratching my head.

Matt

[TopCatGr58]

Okay Matt,

Let's get back to basics. The Orange and Grey leads from the coils go TO the igniter unit, they are the GROUND part of the coil circuit, and the igniter unit controls when the circuit is completed to ground which energizes the coils. The Red/White striped wires going to the coils are the POWER/Positive leads. When you tested the orange and grey leads, you were testing the Ohmage of the Primary side of the coils alright, and you got the required resistance of 1.5 ohms for OEM coils.

To test the secondary, you put the ohm probes into each of the two spark plugs leads for that coil and check, it should be around 15k ohms!!

To check for "voltage" to coils, ground the ground test meter lead, then touch the positive lead to the Red/White striped
wire(s) with ignition on and you should find 12volts! If not, then you need to follow that wire set thru all the connections to check for corrosion and such!

Use this same method to check both ends of ALL of your fuse connectors in your fuse block! A fuse can look good, but be bad. The Ignition fuse is the far right one, 10 A in the fuse block! The main fuse is the far left 30A on the 79SF, it doesn't have the extra one like the later models!

Your trickle charger isn't putting out very many amps, so it's doubtful that it's causing any problems, but you probably should have it disconnected when starting the bike, using only the battery!

Starting it and running it with the OEM coils for a short time without the Ballast resistor won't hurt them, but you don't want to take it for any extended runs that way! The coils only have 1.5 ohms, so that draws more amps thru the line, with the ballast resistor in line, it draws less amps thru the circuit and the coils, and so they don't heat up/burn up as much. And the igniter unit is designed to handle the amperage load that should come from the current going thru an appx 3 ohm coil circuit, the resistor and then the coil, so if no resistor, then more amperage will be running thru the igniter unit and could eventually damage it, as per the Accel page info, using a coil with TOO LOW resistance will damage the igniter unit, but they are talking about using coils designed for CDI's which run around 0.7 ohms, vs. TCI's which use the 2.5 to 3.0 ohm range!

So, hopefully the Accel coils that were on there were the 2.5-3.0 ohm type and not the 0.7 ohm type, or they could have damaged the Igniter (TCI)unit!?

The igniter unit provides a linked power line to the coils that joins past the ballast resistor, and so during starting, the IGN unit sends full 12 volts thru that line to the coils, then after the bike starts, it stops sending that power and then the coils have to get their power from the other side that is going thru the Ballast resistor!

Well, I bet that is clear as mud now!? HTH.
Keep at it, and let us know! T.C.

[mattfrme]

Hello all,

Well TopCat pushed this electrical trouble shooting along with the info that the primary leads (Orange/Grey) are actually ground. It meant that the Accel coils had been installed incorrectly.

Spark test shows very small spark, but it is originating at point of spark plug (not further up the inner core as it had been)

Ohm test shows infinate resistance (at 1k) across primary posts of coil, however 13 Ohms at secondary posts.

Volt meter shows 12 volts at positive primary.

Today I will reinstall the accel coils (correctly), reattach the tank, and give it a try.

These coils are not labeled +/-, but someone used a marker to write it on.

Also, as orininally installed, they were in the oem location, the rubber boots to the secondary cables were wedged in behind the forward tank grommet. Probably close enough that the spark was being sent across the frame of the mc, not to the plug.

I am most likely going to need to replace them, but perhaps there is enough life left to get this babe to start.

Just one time is all I ask. just start 1 time...

I will keep you posted.

Matt

[mattfrme]

WOO HOO!!!

She Started! I rode it around the driveway!!

Ok, put some new plugs in, moved the coils, vroom, vroom,vroom. No back fire.

Of course now there is a gasket leak on the left engine cover.

Need to dial in the Gastank's new lines, check the brakes, could be on the road official in a few days.

The moral of this is that I could never have done it with out this site, and with out the help of all you greal people.

Stay safe

Matt