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**DiverRay** · 05-27-2008, 02:43 PM

Welcome to the site!! You will need to stop buy in June, if you don't make the Yosemite Rally. Check the solder joints on some of the switches, most notably the ignition switch! The brown wire carries the voltage to the rest of the system FROM the ignition, and the connector can get bad there. IF you do not show a charge with a VOM, check for the ground connections and the six pin connector BEHIND the fuse block. IF you have the factory glass fuse block, REPLACE IT, as it is probably the problem.

**3Phase** · 05-27-2008, 03:14 PM

Thanks, Ray, after I sort out the headlight and fix a now-sticking float in #3 carb (grrr, R&R the carbs again) I'll see how she runs out on the road again.

At the moment I'm not getting power on the white wire from the alternator to the headlight relay.

Jumping the relay powers up the headlight reserve lighting unit and I have high/low beam and indicators on the cluster.

The lights all worked before I cleaned the harness.

I'm guessing that I used too much dielectric grease and dielectrically insulated one alternator wire/connection somewhere (tach works/headlight relay doesn't) or I managed to break the diode in the wiring harness that sends DC to the headlight relay.

Where is that diode, anyway? I suspect it's buried in the least accessible part of the harness in the middle of the largest bundle of wires under the most electrical tape... I so hope it's just a bad connection.

Coffee's ready -- back to the V.O.M. and carbs!

Regards,

Scott

**DiverRay** · 05-27-2008, 05:07 PM

Scott,
The diode IS buried under the biggest bunch of tape!! Do a search on "headlight diode" and you should find the thread that Jerry had, showing the position he found the diode in. As my two bikes are early, I don't have the diode. I can't really help much, but you may be able to run a 1 amp diode from Radio Shack on a new wire, from the Alt to the relay.
Check the June 13 &14 Yosemite Rally if you would like to meet Uncle Spot, LoHo, and TKat!!

**skids** · 05-27-2008, 05:39 PM

You could do better by putting in your own relay unit and a switch to turn the headlights off and on.Personally, I think that cutting the wire sheath and looking through the spaghetti is not worth it.

Originally posted by DiverRay
Scott,
The diode IS buried under the biggest bunch of tape!! Do a search on "headlight diode" and you should find the thread that Jerry had, showing the position he found the diode in. As my two bikes are early, I don't have the diode. I can't really help much, but you may be able to run a 1 amp diode from Radio Shack on a new wire, from the Alt to the relay.
Check the June 13 &14 Yosemite Rally if you would like to meet Uncle Spot, LoHo, and TKat!!

**3Phase** · 05-27-2008, 11:38 PM

Wow!

The weeks of inspection, repairing, rebuilding,
re-manufacturing, prep work, and detailing paid off
in spades!

The bike runs smooth as glass and the 160mph
speedometer I snagged from the junk yard and
rebuilt works too! Yeeessssss! <pumps arm>

The white wire to the headlight relay still doesn't
have any voltage but the charging system is good with
14.5 volts at 1500 rpm and all of the turn signals flash
nicely now, thankyouverymuch....

I have no fear of tearing down any wiring harness
and after seeing the picture of that ugly splice by the
diode I think I'll just pull the harness and do it all
over again.

The starter relay has worked only when it felt like it
since I bought the bike and I was hoping that cleaning
up the connectors and grounds would take care of it
but no dice.

It will turn over the engine which then fires until I let
off the starter button, then the engine dies. I need to
go through the shop manual and schematic again as
Yamaha did not include a kickstarter, just a rubber
plug where one would be that I can gaze at longingly
while the electric starter button does zilch, zip, nada,
nothing, zeeero.

On the bright side, I discovered a simple procedure
that stopped my carb from overflowing into the airbox:-

1) Take the bike out of the garage so if it floods
and catches fire it doesn't burn down the house.

2) Keep the fire extinguisher in my hand as I crank
over the engine.

That ensured that the bike did not leak a single drop
of gasoline (or anything else) and I was able to give
her a test ride. <chuckling>

I'm putting the finishing touches on the speedometer
tonight and now that I know it works I'll seal it closed
permanently after I check its calibration. Yes, I have
pictures and I'll take some more as I go.

I'm looking forward to Yosemite!

Regards,

Scott

**boyat68** · 05-28-2008, 03:13 PM

3Phase:

As far as your carb overflowing in the air box; What I discovered was that the floats were hanging on the gasket edge inside of the float bowls when the bowls were low in fuel, such as running the carbs dry after turning off the fuel supply. When there is full fuel in the bowls, the float only falls as far as needed to allow full bowl. If the float falls farther down in the bowl because of low fuel then in hangs allowing fuel to flow in the air box. You need to correct this by trimming the inside edge of the gasket and bend the floats a smidgen down and in as well as setting the back tang on the float so that the float only falls just a couple of mm. I suspect that bikes without vacuum flow control is prone to the above condition as the fuel is cut off after every ride and during the time of the next ride, the fuel evaporates a bit lowering the float that hangs and when the fuel is turned on, the problem exerts itself.

**3Phase** · 05-28-2008, 11:52 PM

Leaky #3 Carb

Originally posted by boyat68
3Phase:

As far as your carb overflowing in the air box; What I discovered was that the floats were hanging on the gasket edge inside of the float bowls when the bowls were low in fuel, such as running the carbs dry after turning off the fuel supply. When there is full fuel in the bowls, the float only falls as far as needed to allow full bowl. If the float falls farther down in the bowl because of low fuel then in hangs allowing fuel to flow in the air box. You need to correct this by trimming the inside edge of the gasket and bend the floats a smidgen down and in as well as setting the back tang on the float so that the float only falls just a couple of mm. I suspect that bikes without vacuum flow control is prone to the above condition as the fuel is cut off after every ride and during the time of the next ride, the fuel evaporates a bit lowering the float that hangs and when the fuel is turned on, the problem exerts itself.

You know, that's entirely possible so I will check the gasket and floats again -- thank you!

I didn't find the threads here about trimming new float bowl gaskets and allowing the float needle seat o-rings to "soak" overnight to expand and seal until after I had already cleaned and reassembled the carbs and I haven't been back into them, yet.

#3 is the only carb that broke a float bowl gasket when I opened and cleaned the carbs. I had to buy one new float bowl gasket for #3 and one new main jet , a 110, for #4 because that jet was cracked (overtightened by P.O.) and its little flat head fell off when I tried to remove it.

Everything else was servicable but dirty and clogged with gunk, rust, and mineral deposits. The #3 main jet and emulsion tube were completely plugged with a inch long growth that formed around a hair that got into the jet and tube, then sat for years in the garage. The hair looked the same way as a string left in a glass full of saturated sugar water. For some peculiar reason the bike chugged a little and lacked some power. <wry grin>

I don't have any pictures of the carb cleaning. Everyone has seen dirty carbs before and I really didn't want to handle a $400 mobile phone camera whilst cleaning carburators. It just didn't seem like a good idea with a plastic phone and all that gas, grease, and carb cleaner.

I wasn't able to do any work on the bike today. I went with a buddy to get some tractor parts and do some grading so I didn't get home until it was almost dark.

The photos of disassembling, cleaning, and reassembling the speedometer and tachometer are finished. I have to upload and label them and think of some kind of narrative for a new post.

Regards,

Scott

**boyat68** · 05-29-2008, 05:07 AM

3Phase:

Gaskets can be coated with Vaseline when assembling. This (Vaseline) is pressed into the gasket material and allows many removals without sticking to the metal.

**skids** · 05-29-2008, 07:10 AM

You are right about carb cleaner and plastics. I have some permanent 3-D fingerprints on the garage telephone receiver.

**oldyam80sg** · 05-31-2008, 01:37 PM

I found the diode in my SG harness and it was turned into a powdery mess.The bike still started though i took a diode from a different harness and replaced it.

**3Phase** · 06-01-2008, 05:33 PM

Originally posted by oldyam80sg
I found the diode in my SG harness and it was turned into a powdery mess.The bike still started though i took a diode from a different harness and replaced it.

This was a self-kill for me. I broke the anode lead off the ceramic diode as I cleaned the connectors and the harness. I had no idea that diode was even in there. The diode in mine is right at the curve of the harness where it tucks around the frame and splits off to the headlight relay.

Someone had been into the harness before. One half of the diode's insulation jacket was missing with the connectors soldered together and there was masking tape on a few of the harness splices instead of electrical tape....

Regards,

Scott

**wa407mpp** · 06-01-2008, 05:47 PM

starter solenoid

That starter solenoid can be disassembled, cleaned, and repaired. Just unsolder the leads and take it apart, no big job.

**3Phase** · 06-01-2008, 06:14 PM

Re: starter solenoid

Originally posted by wa407mpp
That starter solenoid can be disassembled, cleaned, and repaired. Just unsolder the leads and take it apart, no big job.

Thank you, I'll check it out. It's one of those maddening intermittent faults, so I'll have to wait and see if I fixed it.

I have traced all the wires back to the handlebars and checked the ballast resistor connections for the, "... it starts and runs until the start button is released ..." problem. Everything there looks fine.

The connector from the handlebar killswitch and start button to the main harness had one broken locking tab so I cleaned it again and put a zip-tie through he connector.

The rubber mount for the emergency ignition cut-off (tipover) switch was torn so the switch was hanging a little sideways. That might have been the problem.

After waiting a week I finally got my valve shim removal tool yesterday so I checked the valve clearance and had to change all of the exhaust shims.

With the valve clearance set I ran a cold compression test: 145 - 147 lbs in all four cylinders <Snoopy happy-dance>

Today I'll re-check the float level, synch the carburetors, then see how it goes from there!

Regards,

Scott

**AlanB** · 06-02-2008, 03:46 PM

Hi 3Phase,

Tip-over switch does not bypassed; just disconnected. Taking it out will allow you to check if that is your problem. Many of us run without the tip-over; please yourself!

AlanB

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