Where to start... (electrical)

New battery, cleaned & bench synched the carbs, new fuse box & fuses.
The bike does start, and even idles (rough) when warmed up.
I tested the 4 wires on either side of my 4 fuses with a tester light and it "lights up".
Now my problems:
1. I'm mechanically inclined but illiterate electrically.
2. My headlight, turn signals have no juice.
3. Horn doesn't work but I do get the tester light to "light up". Horn never was great, even when brand new.
4. Number 1 & 2 exhaust pipe hot, #3 warm (I think heat transference), #4 cold.
5. I have a Haynes manual with schematics but it might as well be in Chinese because I can't "read" a schematic.

I do have a voltmeter but it came with LIMITED instructions.

Where, what, how... do I test/fix my problems?
Any help would be GREATLY appreciated

 

Best advice is tackle 1 thing at a time or you will drive yourself crazy.

Start with 3 and 4 not hot. Check if you have spark. If you have spark try some starter fluid, could be fuel issue. Let us know and we can go from there.

For your headlight test the relay located under the TCI on left side. Electrical chapter in Haynes has detailed instructions on testing the relay.

Worry about the horn and signals after solving these two but a bit of advice. the old fuse panel can cause a ton of issues, including the headlight, horn and signal issues lie you are seeing. You should really replace it with a blade type holder.

 

Thanks bill. I guess I should've elaborated a little more. I do have new fuse holders with the blade style fuses. Sounds good if we start with the "not hot" issue first. I used the aforementioned tester light on the plug boot of #1 & 2 (the 2 hot ones) and the tester lit up as I cranked it over. The #3 & 4 (not hot ones) "sorta" lit up with a very faint almost green flicker.
Aren't there 2 coils under the tank that send spark to the plugs? It looks like the coil on the left side sends spark to #1 & #3, and the one on the right send to #2 & #4. Something I should be "testing" there?

 

There are 2 coils but they feed 1 & 4 and 2 & 3.

The plug caps just screw on - could be corrosion or even the cap may be corroded. I'd remove the caps and check the wire.

The Haynes manual does show how to measure the coils resistance. It could be good to check that. Also make sure your plugs are clean and the gaps are correct.

 

Yes you are correct sir, on "There are 2 coils but they feed 1 & 4 and 2 & 3."
Like I said I know absolutely nothing about electrical. I took the boots off and stuck my my tester into the wire and still the little trickle of juice. I unbolted my coils from the bike and right coil has a r/w & gray wire, left has r/w & orange wire. I read the section in the manual and the diagram has the multimeter set on Rx1 for primary, Rx100 for secondary.
Umm... mine has X1k and X10 OHM settings. Is that the same?

 

You can still us it difference is scale. the x1 scale a reading of 10 qould be 10 ohms on the x10 scale a reading of 10 would be 100 ohms. You are looking for 11000 ohms so on your x10 scale you should see 1100

Hope that helps

 

On the thin low tension wires (Primary coil check?) a reading of 2.5 ohms +/- 10% should be obtained.
So on mine it should be a reading of 250 ohms set on the X10 scale?
Sorry for being so frekkin' illiterate on this subject but I'm tryin'.
Thanks

 

Me again... am I even in the right direction checking the coils? I mean, I have half of each coil working? Is that possible?
Should I be checking something else for a weak spark?

 

Anyone that wants to chime in on this thread is more than welcome.
I'm sure bill is getting tired of my newbie questions...

 

Well it could be one wire on each coil is bad but that is not very likely. My bet would be 2 things - your weak spark is either the boot connection or the boot is corroded/bad.

If the coils and boots look good shoot some starter fluid in and see if the cylinder fires. If it does you have a fuel issue and we need to look at the carbs.

No problem - 2.5 ohms would be 2.5 on the x1 scale and .25 on the x10 scale. It is times 10 or times 1 of the reading.

The smaller wires are the primary.

 

Okay I got a reading of about .20 checking the coils (both the same reading) at the plastic connectors. Umm... the multimeter was $4.99 at Harbor Freight, so how accurate is that.
Now when you say shoot some starter fluid in... shoot what and where?
Will it prime the cylinder to start running on gasoline or will the pipe get hot from just shooting?

 

You can shoot the starter fluid (which can be purchased at any auto parts store) into the vacuum port of the manifold. It is possible you are not getting fuel in those 2 cylinders. It will run for a bit until the starter fluid burns off. Will have to reevaluate your carbs and float levels if the starter fluid works.

Also we have been assuming you have a weak spark but after reading your post on the tester that could be normal operation. If your circuit tester is an AC type some will light up red on one phase and green on the other. Kind of complicated to explain.

I use an extra spark plug and a glove to test for spark. Touch the plug to the engine case and turn over the engine watching for a spark. If you see a spark it should be good enough to fire the cylinder.

 

Ahh... excellent bill. Thank you so much for your help. I'll be trying that tomorrow morning.
I'll get starter fluid and an extra spark plug.
Thanks again

 

Just to allay one worry:

"......the multimeter was $4.99 at Harbor Freight, so how accurate is that? "

I have seen multimeters fail, but never seen one give a false reading. My personal favourite meter was about that price at Radio Shack in 1975!! Still going strong (and dead accurate according to the digital piece of nonsense I was talked into by a fast talking salesman)

It's the bells and whistles that make expensive meters expensive!

 

Ooops!

 

How to use a multimeter

Best way to describe all the functions, and how to use them I find is to work your way through this web site. I makes you plug in leads and take readings on the web page so you will not damage the real meter if you make a mistake. You dont need to be technicaly minded to do these exercises but I will add it would be worth having your own meter beside you at the same time.

Using Multimeter exercises online

Big Ross is right do not worry about meter readings being 100% true. Near is often good enough. If it is faulty there would be a huge difference in the readings. At work I have workshop meters worth £800 that get calibrated each year. But in my tool box I still have my trusty £14 five year old DMM for on site stuff.

 

Alright wild bill I checked the spark as per your instructions. Oh I definitely have a spark on #3 and 4, so it's not the coil or anything "backwards" from there.
Alright time for a "newbie" question... upon further inspection of the exhaust boots (carbs to engine) I saw rather large cracks, splits, whatevers, on the boots. Mainly on #3 & 4. Let me guess the pistons sorta suck gas in from the carbs to fire and too much air is getting in?
Just a side note... SOB I can't believe that carb 3 & 4 have problems! I cleaned, float adjusted, bench synched, everything, all the same.

Big_Ross>>> I'm sure the multimeter is fine as you stated. I'm sure it was "user error".

Kenbo>>> Excellent tutorial! I bookmarked it for reference. Yeah okay I failed until I got it right. That was just the newbie explanation/instructions I needed.

 

In regard to the cracks/splits in the boots: As bad as they may LOOK quite often they don't go all the way through. You can use black RTV or "liquid electrical tape" to seal them. The test for a vacuum leak is to spray carb cleaner or go probing with an unlit propane torch to see if the engine changes rpm. Unfortunately, it has to be running to do that. Go back and recheck everything, especially how you have the coils hooked up. Having spark only on #3 and #4 would mean HALF of each coil is working (a conclusion you already reached) which I highly doubt. Remember one fires 1 & 4, the other 2 & 3. There's something else going on.

 

Sorry I'm behind - spent yesterday replaced gaskets and pulled the carbs on my bike.

Anyway since 1 and 2 heat sounds like your coils are fine. Did you try starter fluid yet? As Fitz said the cracks my not go through and you should at least be able to run.

If the starter fluid works you definitely have a fuel issue. I know you bench synced, try turning the idle screw in some more to open the butterflys a bit more

 

Yeah I first fired her up and let her get a little warm since she can be a bit cantankerous at first start. Anyway, once she was warm I took the little nipple off the fitting on the top of the exhaust boot of #4 and sprayed a shot of starter fluid in there. The rpm's took off like a scalded dog. I did that a few times after the rpm's died down to a reasonable level. Well #3 started firing for know known reason as that pipe got as hot as #1&2. And #4 was definitely getting hot the more I shot starter fluid in, so I'd say I've got good firing on all. It must be the carb on #4 which is better than being electrical, but still a pain in the arse to take the carb rack off again. By the way I loosened the drain screw on bowl #4 and gas did drain out.

 

Cool some of the heat could be from firing with the starter fluid. Sounds like fuel. Several things you can try.

If you crank the idle screw up you can see if 4 starts firing. If so it's butterfly is closed too tight at normal idle ( bench sync should have left it a bit open - they should all be the same but if you got it tighter...). If that works you just need to sync using a vacuum gage or sync tool of your choice.

I would try that first. If it doesn't work pull the carbs and check the jets. I would rebench sync While you are at it.

 

This evening I'll check my schematics and give you some steps to trace your electrical issues. We are seeing the light at the end of the tunnel!

 

Sounds as though electrical issues have been eliminated as being the cause since all 4 have spark?

 

He has horn and headlight/signal issues too. Been trying to work one issue at a time

 

Sorry, had to go back and read the whole thread again. Thought the only electrical issue was ign related. Horn headlight, signals? Mere safety items, all possibly fusebox related. Seriously tho, I agree. Needs to run first. One dragon at a time.

 

We'll start by assuming your fuses are fine since you replaced the block and get voltage on all 4 fuses.

For the horn you should see 12V from the Brown wire to ground (negative side of battery or anyplace on the engine). Test this using the meter's voltage measurement.

When you press the horn button it should take the pink wire to ground. Test this with the meter in same way you checked the coils using the resistance measurement.

Unplug the pink wire from the horn for this and the next set of tests. Measure the pink wire to ground and press the button. Should be open (infinite) when the switch is not pressed and 0 when it is pressed.

You probably have voltage on the brown wire based on what you said earlier. If the horn button does not ground the pink wire you need to start tracing the wire back looking for a bad connection.

The pink wire goes up to the switch assembly. In the headlight bucket you can unplug the connector to the switch. Check resistance from the pink wire at the horn to the pink wire in the connector from the wiring harness. Should be near 0. Check the Black wire in the same connector to ground - should read near 0.

If that is OK you need to check the switch. In the connector that goes to the switch, check the Black to the pink wire. Should be open (infinite) when the switch is not pressed and 0 when it is pressed.

If that does not resolve the horn problem we can see what else may be going on.

One of the things that is common to all your issues is ground. You may have a bad ground someplace. We will tackle stuff one at a time though.

 

As soon as the weather warms up a bit more this morning I'm going to check out that #4 carb. Since it's on the end of the rack I was going to take off the bowl and hat and have a look see if anything is obvious before I totally remove the carbs.
I don't know why anything would have changed after sealing them up, but if the floats are "hanging" lower (on the bike) than it should, it wouldn't fill the bowl with enough fuel? Or do I have that backwards?
While I had that one apart I was going to blast it with my air compressor too.

 

Won't hurt to take a look. As gas fills the bowls the floats are pushed upwards to close the needle. The jests are low enough that it would have to be very low to have a starting issue.

My bet is on the butterfly. Air needs to flow to suck gas from the bowl. If your butterfly is closed completely no gas will flow. That is why I recommend turning up the idle screw it will open the butterfly. You will have a higher idle but if #4 fires you will know the problem and it can be resolved by syncing.

 

Take this comment with a grain of salt, cause I certainly do.
I told an old motorcycle mechanic that I used starter fluid on my bike once, and he about rung my neck. "Never use that junk unless you want to blow up your motor", was his rant.

Ether is some pretty nasty stuff. The best it will do is burn out the fuel flooded in your cylinder. When it ignites, it creates way more pressure than the gas mixture. Use it sparingly.

Your pilot circuit may also be clogged. Once you get the bike started, crank it up to see if the other cylinders spurt to life once the rpms get above 3500rm or so.

 

Sadly I haven't had the time to do anything with my bike lately. You know those darn things like work, family, responsibilities, voting, keep coming up. *lol* I hope to get back into the mechanics soon though.