'75 XS no Spark so I want to change the ignition system. Need advice

speeedracer27 said:
I don't have a battery in the bike. Using a jumper battery and cables. Negative to the frame, positive to the main wire (before I took out the battery box with all the electronics) and to the coils.
Click to expand...

OK Got it
Please disconnect the + 12 V when not needed.
I would still draw a separate ground wire from Coils and Ignition since this is a common fault
And the best way to ascertain that the ignition has the right physics
Jumper to the frame might not be good enough not go trough paint and such.
The Capacitor can be old but often things take a positive turn with correct ground and power
The upside 12 V is simpler to measure .

The Diode I cannot figure out Quickly sorry I have never seen it and it is wired into starter solenoid
Downside as it seems ..Hitting the start button grounds that Downside.
I Dont know the internals of the starter Solenoid.
 
From what I gather, the coils have one hot wire going to them (feeding from a red/white wire and the other wire goes to the points). The coils are grounded to the frame. I don't think they have a separate ground wire. When I say I hook the negative jumper lead to the frame, I really mean the engine. The diode is the small guy hanging right by the coils with black and white/black wires going to it. I've pretty much eliminated the entire wiring harness, ignition switch and engine kill switch by jumping the coils. Still no spark. It has to be one of the 3: coils, points, or condenser. Am I missing something in my line of thinking?
 
speeedracer27 said:
From what I gather, the coils have one hot wire going to them (feeding from a red/white wire and the other wire goes to the points). The coils are grounded to the frame. I don't think they have a separate ground wire. When I say I hook the negative jumper lead to the frame, I really mean the engine. The diode is the small guy hanging right by the coils with black and white/black wires going to it. I've pretty much eliminated the entire wiring harness, ignition switch and engine kill switch by jumping the coils. Still no spark. It has to be one of the 3: coils, points, or condenser. Am I missing something in my line of thinking?
Click to expand...


Aeehhh ... that was actually a trick Question I did not remember exactly since I have Boyer Bransden
But if You look at the Picture ( Excellent Pictures ) of the Coil at post # 14 second picture there are 3 wires Brown Orange and to spark Plugs
AS in the wiring schematic ( that was a bit bad )
BUT there is also a black one on the underside
And you can also see a Black wire going to the Top engine Mount
At this point in time you most likely not have connection between these black to clamp and even less to the corresponding ones at the Points at the other side of the engine ..to the minus clamp
The clamp is at a better place than on the frame .. But I would assume not good enough
Because the top mount can have rust and lost connection .If the wire is not Broken altogether .
So I apologize if I sound like a parrot --- Physics is not ascertained .
Perhaps moving the clamp to the top engine Mount nut makes a difference ..
But I am pretty certain ..There is a need for servicing the ground points cleaning and using Carborundum paper
And I then Use Copper grease but there are better ones
Or jump both ground and Power. for test
I may be wrong but that is how I feel --- It can be one of the remaining coils, points, or condenser.
 
Excellent, did not realize that there is a black ground wire that comes off the coils. From experience, do you recommend the Boyer set up over Mike's. I prefer a modern ignition and charging system. Hell, I don't even care if I have to replace every wire loom in the system with a new one. I bought this bike over a new Triumph Scrambler because I love the way it looks and the 650 is bulletproof. I figured on spending a small fortune on making it as modern as possible. Wait until I start asking questions about dual Brembo for the front...My dog is anxious for me to get this thing going so he can cruise in the sedecar!
 
Boyer is a upgrade in reliability from Mikes, also has much better support. I've been running Boyer and have had no problems. If you get the one with the blue box the spark is as hot as anybody's. Not hard to install. Comes with everything you you need except for locite, for engines from 79 and older. 80and newer need the bushings installed in the cam.
 
speeedracer27 said:
Excellent, did not realize that there is a black ground wire that comes off the coils. From experience, do you recommend the Boyer set up over Mike's. I prefer a modern ignition and charging system. Hell, I don't even care if I have to replace every wire loom in the system with a new one. I bought this bike over a new Triumph Scrambler because I love the way it looks and the 650 is bulletproof. I figured on spending a small fortune on making it as modern as possible. Wait until I start asking questions about dual Brembo for the front...My dog is anxious for me to get this thing going so he can cruise in the sedecar!
Click to expand...

I am not Qualified when it comes to what system is best .
Boyer is a well reputable company . Over many different bikes that has a service department and can do fault finding
I Would assume a better ignition --- on the other hand if one aims at a bigger " Whole " Set I would perhaps getting it from the same place. Not necessarily from Mikes XS
Since I have had a " Zero Cost " approach others here are more qualified .
But having said that if I was to spend Money ( as a rich man ) I would Search for an adjustable ignition curve
Mostly for the interest and fun.
Not because it is not possible tune it.
 
When checking for spark, you used a grounded spark plug. That means that a bad plug or cap can be the problem as well. In the old days, I used to unscrew the spark plug cap, and hold the exposed end of the spark plug wire maybe 5 mm from the cylinder head. The spark should be able to jump that gap.
 
arcticXS said:
When checking for spark, you used a grounded spark plug. That means that a bad plug or cap can be the problem as well. In the old days, I used to unscrew the spark plug cap, and hold the exposed end of the spark plug wire maybe 5 mm from the cylinder head. The spark should be able to jump that gap.
Click to expand...
Great idea. I'll give that a shot
 
Get a test lamp, can be a bulb with two wires or a proper test lamp, fasten one wire to the earth on the frame, and the other to your battery, lamp should light, then put a piece of paper between the points, both sets, turn on the ignition, lamp should light on the red\white wire to the coils, also it should light on both /either wires coming out of the coils, if this is so power is to and through the coils.
Down at the points test at the terminals that fastens the wire to each points set, light should light. While you have the test lamp on one of the points wires and the lamp is lit, pull out the paper if the lamp goes out that set of points is good, then do the other set.
That proves the low tension side of your ignition is working. If you still have no spark check the high tension side of the coil plug lead, take off the suppressor cap and bare the wire on the end of the lead, check for a spark.
 
Rasputin said:
Get a test lamp, can be a bulb with two wires or a proper test lamp, fasten one wire to the earth on the frame, and the other to your battery, lamp should light, then put a piece of paper between the points, both sets, turn on the ignition, lamp should light on the red\white wire to the coils, also it should light on both /either wires coming out of the coils, if this is so power is to and through the coils.
Down at the points test at the terminals that fastens the wire to each points set, light should light. While you have the test lamp on one of the points wires and the lamp is lit, pull out the paper if the lamp goes out that set of points is good, then do the other set.
That proves the low tension side of your ignition is working. If you still have no spark check the high tension side of the coil plug lead, take off the suppressor cap and bare the wire on the end of the lead, check for a spark.
Click to expand...
Awesome directions. Thanks.
 
The ground wire attached to one of the coil mounts comes out of the main harness. It is a ground wire for multiple components the harness connects to and not a coil ground wire. Yamaha just happened to attach it to a coil mount for it's frame grounding point.
 
If you should end up going for a total rewire, a Motogadget M unit may make sense. Combined with a Vape (Powerdynamo) CDI ignition/ PMA charging system, you will have a pretty modern system. And your wallet will be close to 1000 dollars lighter.
 
arcticXS said:
If you should end up going for a total rewire, a Motogadget M unit may make sense. Combined with a Vape (Powerdynamo) CDI ignition/ PMA charging system, you will have a pretty modern system. And your wallet will be close to 1000 dollars lighter.
Click to expand...
That she's like something I may actually consider. Do you have a link to this set-up? I'm OK with letting go of some cash for this project.
 
5twins said:
The ground wire attached to one of the coil mounts comes out of the main harness. It is a ground wire for multiple components the harness connects to and not a coil ground wire. Yamaha just happened to attach it to a coil mount for it's frame grounding point.
Click to expand...

Makes sense and Explains why it is not on the Schematic . Every day a new lesson learned
However the Physics problem is still there -- that ground point needs to be connected as any electrical wiring to the Circuit
And downstream connect to the Minus on the battery ..
Difficult to see how that can be avoided if not separate ground wires are drawn
Rasputin # 24 has a promising method
But come the new electronic system the problem can be even worse
A Dutch gentleman had a perfect central ground point as for commercial trucks
But then he most likely introduced voltage ( unknown how ) spikes that made the electronic box misfire
Separate ground wire seemed to solve it.
 
speeedracer27 said:
That she's like something I may actually consider. Do you have a link to this set-up? I'm OK with letting go of some cash for this project.
Click to expand...
I'm reading up on the Motogadget and this looks like an pretty awesome setup. Wonder if anyone has a new wiring schematic for the 650's with the Motogadget module. The keyless feature sounds very cool. I've rewired my entire fishing boat once , and understand the importance of proper wiring. That was like having 3 motorcycles in one project. Even WHEN I figure out my present issue, I may elect to go that route.
 
A stock, unmodified XS650 is indeed a 360 degree engine (pistons go up and down together) Modifying the crankshaft, camshaft and ignition to 277 degrees or 270 degrees is a fairly popular mod. Pretty much the same thinking as in the new 700 cc Yamaha twins (MT/ XSR/ Tracer/ Tenere)
 
Yes, but you really don't need all that fancy stuff. The 650 works fine wired the way it came. Many have been putting down the road 40+ years like that. Yes, go through the wiring and repair any rubbed bare wires and loose connections. You'll usually find a few after all this time. A thorough wiring and connector inspection is one of the first things I do to one of these when I get it.
 
Wanted to give an update on the project. I got fed up with the whole points thing and didn't want to throw any $ into an antiquated system. Instead I ripped the whole bike apart and replaced everything. Mike Morse, from 650 Central in CA was super helpful http://www.650central.com/
Mike gave some great advise and I purchased my Boyer ignition set-up along with a solid state regulator and some other cool stuff. I also opted for a new wiring harness from Mike's XS. The install was pretty straight forward. Timing was a little trickier (you'll need a timing light to dial it in). Ran into a bunch of small stuff along the way (like the fact that P.O. had no business wrenching on this bike). Missing carb springs, clutch assembly installed all wrong, etc... Took some time to sort it out and find the correct parts. So far I replaced:
Entire electrical system - Boyer ignition, Solid State Reg, wiring harness
Rebuilt the tach (that was an experience). Made a great tach out of 2 bad ones
New fork seals
Tapered steering bearing
New wheel bearings and seals
Rebuilt carbs (jets, float, needle, seat)
Replaced both petcocks (Mike's XS had a set of the correct ones. They are proud of them, but the cheap set on eBay were total garbage, didn't line up and leaked like hell.
Rust blasted and sealed the tank (look brand new inside)
New throttle cables
New piston rings (honed cylinders)
Resurfaced valve seats
New valve seals (adjusted valves, of course)
New 13MM master cylinder (650 Central)
Caliper rebuild kit
Super cool LED headlight was a direct replacement, plug and play. Surprised and very happy about that
Bunch of new fasteners and other shiny stuff
New tires
Oil Filter Kit (Mike's XS)
New sump filter
K&N style air filters
New AGM battery
New horn and flasher relay
Other stuff I can't remember
The bike runs like a dream. Super hot spark, charges like it should, shifts like butter and altogether looks cool.

Some stuff I'm trying to dial in: (advise and smart a$$ comments always welcome)
Can't seem to figure out my turn signals. The front signals are integrated into the new (super cool) LED light. I'm following the schematic. Dark Green and Chocolate wires for turn signals, but I'm getting nada. Perhaps it's my switch? I just put in a new flasher relay (of course after my clutch cable debacle I'm not dismissing a new part being bad).
Speedo not registering. I can spool up the cable with my drill and it works, but them when I connect it to the worm gear on the front wheel, no go... Maybe I didn't set up the front wheel correctly, but that seems a bit hard to accomplish. I looked at the diagram and it looks correct. Not sure there are too many ways to screw that up. This is a perfect set up for someone to call me out on it...
The bike is cold blooded. I expected that. What I didn't expect is that only one of the carbs has an enriching valve on it, and it works like crap. Once I get it started, for the 1st time, it's a one-touch machine. However, I don't want to burn up my starter one morning... Anyone know of a better solution (choke kit or a fix to this issue)?
Front caliper was so frozen, Disney wanted me to pay royalties. I soaked it for days in every chemical known to man (yes, I'm replacing the seal kit so I was not worried about the rubber stuff swelling). I finally found a neat trick using a grease gun and after 2 hours and exhausting my 4-letter vocabulary, I was able to get the pistons to come out. (I realize I could have bought a new caliper for $99, but where's the fun in that)!? I'm also soaking them in some rust blaster (for good measure) before attempting to install my front brake (Don't worry I never left my street on the test ride, so my rear drum was sufficient top stop me from a blistering 25MPH terminal velocity).
As soon as I sort out my laundry list, the sidehack gets its turn. Plan on dismantling it, setting up a point booth (state-of-the-art 10x10 EZ-UP with some plastic drapes) and applying copious amount of top secret paint to the entire project. (Spoiler alert; taking it back to semi-original 1975 color scheme).
Well, that's it for now. I'll update with before, during and after pics, once the project is complete. Thanks for everyone's help and advise. Please keep 'em coming. This has been fun, frustrating, at times, and educational. Glad to know there is a pretty cool community of XS 650 gearheads out there.

I chose to do this project rather than buying a new Triumph Scrambler with a side hack. Perhaps that was a lapse in judgement, but I was drawn to the 45-year old Yamaha and felt like I wanted this XS to be something special. I'll revisit this decision in one year from now with some hindsight at my disposal. Stay tuned...
 

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