1976 XS650-C Project From Ireland

beano

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Hi all, long time lurker first time poster, I've been reading what seems like hundreds of threads for the last year or so, the knowledge available here is absolutely vast and has really been a big motivation to get this project up and running.

So anyway I've decided to attempt to put my fathers old xs650 back on the road, its been parked in the shed since 1993 and he passed away in 2005, so its more of a sentimental thing to get her back running etc and I would like to do it properly and get her back to running and looking as well as possible. I don't plan on rushing it and it will take as long as it takes.


Heres a pic of the bike taken in the early 80's.


gVwg4W6l.jpg



And here what she looks like now all these years later.


gCotFyDl.jpg




From what I can gather from the frame and engine numbers the bike appears to be a 1976 C model however the engine has been replaced at some stage with that from a 1975 B model, its also running BS38 carburetors and a Newtronic electronic ignition system.


Z0bEwlEl.jpg



Anyway the first thing I want to do is get her running, and see how healthy the motor is, then we will progress from there hopefully. I know I have my work cut out so expect plenty of noob questions!!.
 
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The paint scheme and side cover label (OHC650) in that early pic indicate a '75 model, or at least the body parts from one.
 
Thanks for the info, the frame number is 447-302xxxx, would this indicate a 1975 model??
 
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That number seems to indicate a European C model, but I'm not much up on serial numbers, or European model variations. I suppose it's possible the European '76 models still came with '75 style paint schemes.
 
It’s something for me to look into down the line alright, I’m a long long way from looking at paint unfortunately!!

thank you for your input, it’s much appreciated.
 
Very nice story beano - best wishes for a smooth return to the road. I had a 1975 XS650B with that very smart black and gold colour scheme back in the day.
FB782595-1A23-4A07-8B57-4A17D3B62DA7.jpeg

Now, I have a 1976 C-model (the formidable, but troublesome Lucille :yikes:) and, at least in Canada and the US, the colour scheme was entirely different.
66656ABE-BA46-436D-856A-43AF29422071.jpeg

The carbs are very similar (both BS38s) but the 1975 had two separate throttle cables while, beginning with the 1976 model, only a single cable was employed. Also, the front brake caliper on the 1975 was mounted to the front of the fork leg, while the 1976 and later caliper were mounted behind the leg.

On your bike, I note that the front fender in the recent photo is from a much later bike (no fender stays which both the ‘75 and ‘76 models normally have) and the front fork / brake set-up appears to be from a 1976 or even later bike - although, we never got the double front disk set-up here on any XS650 model as far as I am aware.

Cheers,

Pete
 
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Good stuff, thanks for the insight @MaxPete your bikes look great, love the retro style fairing on the 75!

The carbs on this definitely only have one throttle cable, but I cannot be sure if they are correct to this bike as of yet unfortunately.

I'm assuming that the fender stays are here somewhere, will have to dig through these and find out for sure.

rWpJMBXl.jpg


Its all too easy to get side tracked with cosmetics, that was a big lesson I learned from my previous projects, so for now I'm concentrating on getting it running. The very first thing I need to do is get spark, that's gonna be my first priority. Hoping to get out at her tomorrow morning fingers crossed!!
 
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From my information the Euro/GB 75b and 76C had similar decals. On brochures and a pic from a guy in England, (Member from this site), the 75C decal didn't extend onto the top of the tank like it does on the 76C.


75B Brochure from the owner of the bike pictured.
75B ImageUploadedByTapatalk1450087601.107023.jpg 75B ImageUploadedByTapatalk1450087567.322799.jpg 75B XS650B 447-502+++ England.jpg


76C Brochures and pic of a Red C.
76c fol1E1_4.jpg 76C xs650C-1.jpg Yamaha XS650B 75  1.jpg 1 1z.jpg 76C fol533_8.jpg 76C  E.jpg


The gauges are a tell.As is the Gas cap.
75B style gauges.................Gas cap
1k 75B.jpgP1000921.JPG

76C style gauges. These are quite Rare as they are a one year/model only set up. The Rev counter especially as it had 3 warning lights incorporated
76C Gauges.........................Gas cap
2z1 76C 1 2.jpgP1000969.JPG
 
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@650Skull fantastic information, you're like some kind of encyclopedia on these things!!

Armed with the above knowledge I went out to the shed this morning and did a bit of rummaging around, and it would appear that the bike is most likely a 1976 C model.

tQOCdQal.jpg


qZN3gKil.jpg


I do remember my father making a big effort to get the bike going again after he got diagnosed with cancer, and he splashed out on a lot of new parts which I collected together and stashed in a drawer some time ago.

The electronic ignition is already installed and I do remember vaguely witnessing the bike running. My brother had to kickstart it because my father had gone too weak to kick it over, but it definitely ran I remember that much anyway.

zhNGaayl.jpg


I also bought a brand new wiring loom as there's only a few strands of household electrical cable being used at the moment, so I'm hoping to get that installed today and see if we can succeed with this elusive quest for spark!!
 
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I had a little play around with it yesterday, when the battery was hooked up and the ignition switched on, the rectifier began to smoke...........not good.

I downloaded a couple of wiring diagrams from the tech section on the site here, which is a fantastic resource I must say, and quickly decided that it would not be possible to work with the existing wiring as it was on the bike.

Some examples of what I was facing:

58opPe1l.jpg


6WGXUjEl.jpg


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So I thought it would just be easier to hook up a brand new loom, at least then I can be sure of the correct colours etc, which should make following the wiring diagrams easier.

3POor8gl.jpg
 
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Your best bet is to get a schematic for a 1976 Euro model and stare at it until you understand what does what and where things go on the bike. You will also need a multimeter (get a decent one - but less than $100 will do it), a charged battery and a supply of fuses (in my experience) many of which you will blow before you're done.

Sorry - but that is the best I can offer - along with the attached files from loyal Forum member Skull who compiled these helpful notes on checking circuits. I am also attaching a 1976 C-model schematic which is likely not too different from the Euro model (it may even be identical) along with a 1977 D-model schematic which is purported to be from a European model (although I cannot confirm this) NOTE: the 1977 in North America had self-cancelling turn signals and that system added several components to the bike (including a connection to the odometer) which are absent from 1976 models.
Skull continuity 1.jpg
Skull continuity 2.jpg
Skull continuity 3.jpg
Skull continuity 4.jpg
75_76_XS650 B&C Wiring.PNG
76C Assembly manual - parts  Manualt19 19.jpg
76C Assembly manual - parts  Manualt27 27.jpg
76C Assembly manual - parts  Manualt28 28.jpg
77-xs-d-wiring-europe.jpg
77-xs-d-wiring-europe-key.jpg


Pete
 

Attachments

  • XS650WiringDiagrams.pdf
    588.7 KB · Views: 178
.I.m not an electrical wizard, not even an apprentice.........After this fault was mentioned i redone the diagram with help from the all knowing.

76C Diagram.......... the red, ( + ), from the battery is wrong. I redone the diagram in this area and the other areas mentioned below

On the Dash it shows a headlight failure warning light. ....................Note; 76C didn't have this ..........Changed; it should have read as a Brake/Taillight warning light......................Note; .Also shows DG, (Dark Green), from the headlight to the switch.......Changed; It should have read G, (Green)................... Caution;..DG, (Dark Green), is an indicator wire and if dirty can be mistaken for a black wire

Redone diagram.
d 75_76_XS650 B&C Wiring and Key Updated 3a.jpg

d 75_76_XS650 B&C Wiring and Key Updated 3a.jpg


Sorry Pete, This was pointed out and corrected after the posts in your Lucile thread.
 
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.I.m not an electrical wizard, not even an apprentice.........After this fault was mentioned i redone the diagram with help from the all knowing.

76C Diagram.......... the red, ( + ), from the battery is wrong. I redone the diagram in this area and the other areas mentioned below

On the Dash it shows a headlight failure warning light. ....................Note; 76C didn't have this ..........Changed; it should have read as a Brake/Taillight warning light......................Note; .Also shows DG, (Dark Green), from the headlight to the switch.......Changed; It should have read G, (Green)................... Caution;..DG, (Dark Green), is an indicator wire and if dirty can be mistaken for a black wire

Redone diagram.
View attachment 124643
View attachment 124643


Sorry Pete, This was pointed out and corrected after the posts in your Lucile thread.

Not at all - I thought I had tracked this all down.

Pete
 
Wow what a great response, you just cant beat the local knowledge that owner specific sites possess. I've made some good progress I think with just working out where everything goes etc, the info in the posts above have really expedited the process so thanks to each and every one of you for the help so far.

So I started by printing out the wiring diagrams for for the headlight shell and began checking off the wires as I went along, it mostly corresponds to the diagram however I don't have an ignition switch and my tachometer has had the wiring removed, so I cant check them but I'm assuming they are correct.

There are some differences between the loom that I have and the wiring diagram for the 76, the details of which I will describe below.

Y4IV2WQl.jpg



As you can see there is an extra red/yellow wire in the left hand switchgear (possible parking light circuit??)

There is a 6 wire connector for the tachometer in the left hand branch of the loom instead of the 4 wire connector in the diagram, this 6 wire connector corresponds exactly with the xs650B set up.

GCCmwVbl.jpg


There is no 2 wire connector (L/R B) on the right hand branch,

I'm also assuming this 5 wire connector (located in the middle of the loom) is for the lamp checker unit? I don't think I have one of those, and Its not necessary anyhow so I will be leaving these blank.

0db472ml.jpg


The orange and grey wires to the points/condensers I think are now redundant due to the electronic ignition.

Thanks again for everyone's contribution so far, its been a real help and I really do appreciate it, hopefully we will have her goin soon!!!
 
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Ok so update time, I managed to hook the important things up and now have power at the coils but unfortunately no spark.

The voltage at both coils is 12.68v. I have also measured the primary resistance and its 3.9 ohms at both coils.

The secondary resistance is 13.43k ohms at the LHS coil and 13.26k ohms at the RHS coil.

I've searched through a few threads and these values seem within spec, does this indicate a possible timing issue??

I'm running an aftermarket newtronic ignition system, its a basic type that keeps the old advance mechanism.

Thanks in advance for any suggestions.
 
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Good morning Beano:

If the coils check out then the next thing to check would be the high tension leads and caps, or the spark plugs themselves.

The HT leads have an interesting type of connector at each end. It resembles a fairly coarse wood screw and it is down inside the spark plug end cap and also at each coil secondary output terminal. The assembly at the coil end is secured by a little threaded cap which screws onto the coil terminal. Inside that threaded cap is a small plastic or rubber ring that tightens down onto the outside of the HT outer insulation.

Basically, you bare about 3-5mm of insulation at each end of the HT lead and spread the conductors out like a flower and then simply screw the lead onto the “wood” screw terminal and tighten it until it (gently) bottoms.

Then tighten the threaded cap (only at the coil end) with the rubber “ferrule” to secure the connection. Also, I would suggest putting a little dab of dielectric grease on the outside of the HT insulation to seal the assembly from moisture.

I’m sure that if you stare at it for a moment, you will understand what to do.

If you are replacing the HT leads - you want the 7mm diameter cable and not the larger 8mm size which is often used on car systems. Car parts places sell it by the foot off a reel.

If the spark plugs are dead - you’ll need two new ones (you should likely replace them anyway).

Pete
 
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Thanks for that maxpete, I should have added that I already removed the coils and cleaned all the contacts.

I also removed the ht leads, snipped a bit off each end to give some fresh wire for the caps and coils to bite in to.

plugs are ok, they spark when I plug them into my Yamaha fzr.

Any other suggestions??
 
Thanks for that maxpete, I should have added that I already removed the coils and cleaned all the contacts.

I also removed the ht leads, snipped a bit off each end to give some fresh wire for the caps and coils to bite in to.

plugs are ok, they spark when I plug them into my Yamaha fzr.

Any other suggestions??

Hmmmmm....sorry, no new ideas at present.

Perhaps the bike is haunted...:yikes:
 
Upon a second look it appears that according to the manual the secondary resistance between the coil and the plug cap is only supposed to be approx 8k ohms where’s mine are reading approx 13k ohms.

Before I go out and buy new leads and plug caps, does anyone know if I should even be getting a tiny bit of spark at these resistances?? At the moment there is nothing at all and my leg is getting a tad weary from all this kicking!!
 
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