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Discussion Starter · #1 ·
These past couple weeks I've been really busy in the shop. Got my cb200s carbs ultrasonicly cleaned, valves adjusted, and points and ignition reset. Worked on my buddies gz250 and found his regulator needed replaced. And finally getting my dad's old cx500 running after a carb rebuild, front brake caliper rebuild, and replacing master cylinder to sell to an acquaintance for a mere $750 (I'm too nice).

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I've decided there may be potential for me to start doing vintage motorcycle repair at my shop as a permanent side hustle, but before I do that I need to challenge myself.

I bought this '79 xs750 a year ago from someone who had it taken apart for some radical project, don't ask me why I have a sickness when it comes to VJMs. Anyway I'm not gonna move forward with my ambition until I have this bike back in full functioning order
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Wish me luck, hashtag douchebag
 

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Discussion Starter · #2 ·
Managed to get it on 2 wheels, now I'm gonna go through the frame and fit the body back together. Unfortunately I noticed a couple things missing:

1 turn signal
1 side cover (bummer)
And the center kickstand

Other than that all of the notably large parts of the bike are all there and the wiring harness looks to be intact. Hardware is gonna be a nightmare in mapping out, but luckily the Haynes manual has excellent exploded views and part legends, I'm sure I'll be having to replace a number of lost pieces though
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Discussion Starter · #3 ·
So far so good, looks like I'll be able to move onto the engine this weekend after I fit the electronics and harness into place
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Discussion Starter · #4 ·
Well I believe I found the probable cause as to why the bike stopped working, looks like the wire connector between the reg/rect and battery burnt and melted. Perhaps too much resistance at the connection? Gonna have to put the part down for a replacement and splice my own wires after I inspect the engine.

Can't imagine the original owner ever questioned this as he had the wires labeled "shit under the battery box" 🤣
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Discussion Starter · #5 ·
Bike chassis is assembled and wiring harness is in place. Gonna run tests on coils, stator and ignition unit and if all checks out the electronics should be functional with a couple small repairs.
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Discussion Starter · #7 ·
Almost had it down to the crankcase, gonna need a ridiculously deep 32mm socket to take out the retaining nut holding the clutch inner drum.

With the crankcase untouched the engine is only missing one right side cover bolt (hardware store alternative) and one clutch spring bolt (ebay replacement) but everything else is there.

On a brighter note, at least the rotor came with the extractor tool attached
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Discussion Starter · #8 ·
So it turns out that it's a lot harder to find size specific extra deep sockets than one might think. I only found 1 website that had one in stock and it looked questionable wether it would clear the primary shaft.

Anyway I was pondering all morning who I might be able to get one from when I came up with the idea to fabricate my own. I cut some 1⅞ DOM tube to 7" and used my CNC to cut out two hole plates, one with the 32mm hex and the other with a ⅜" socket square

After a few tack welds I made a makeshift clutch basket holder out of 2 of the steel clutch disks and a small pair of vise grips and placed it against the back of the casing. With a few small carefully controlled bursts with an impact the nut came out with ease
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Discussion Starter · #10 ·
Great enginuity however a deep offset spanner would have done the trick
Thanks and yeah the manual even suggested a spanner as well, I would have preferred using a proper tool honestly. The 3/8 ratchet wasn't breaking the nut though, you can imagine how nervous I was putting an adapter on the impact to fit. Lucked out that it came off as smoothly as it did
 

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Discussion Starter · #11 ·
Got the crankcase opened yesterday
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I figured I'd shift through the gears before taking the shafts out. 2nd gear wasn't engaging and was making a light knocking noise. Pulled out the primary shaft and dog forks and noticed that the 2nd gear on the layshaft was loose and wobbly. I removed the layshaft bearing housing; and the retaining circlip and copper shim damn near popped right out in my hand along with it
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Luckily the cog pushed right back onto the shaft and only needs a new circlip and shim. My guess is someone shifted hard into 2nd and punched the retainers right off the shaft, I'll bet it sounded like a new years noisemaker whenever it shifted into 2nd from then on.
Anyway I see no reason to remove the layshaft and shift drum since I can clean and lubricate them right in the case.
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One last thing I need to address before I get ready for reassembly is the kick start engagement gear, look at how chewed up the teeth are on that thing

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Discussion Starter · #13 ·
Been working on the carbs for a couple days now, thankfully they were together on the rack. Turns out they are actually listed for the xs850 from 80-82 , which means this is probably one of the last production runs of the xs750 triples. I'm not particularly fond of this style of motorcycle with the curved handlebars and throne seat, but it is interesting to know it's a bit more rare than the standard models.
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Oh and buying aftermarket SS Allen head bolt kits for vintage bikes is well worth the money, especially in comparison with buying just 1 missing bolt from your local hardware store
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Discussion Starter · #16 ·
All 3 carbs are disassembled and cleaned, slide diaphragms and floats are in good shape surprisingly. All JIS fasteners are trashed since someone took a Philips to them, but I probably would have replaced them anyway. Engine reassembly starts this weekend, gonna try and make a time lapse video to share
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Discussion Starter · #17 ·
About halfway through the rebuild and I noticed that I'm missing a small steel ball connecting with the clutch pushrod (#31)
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Apparently it shouldn't stop the building process though since both the ball and rod can be inserted on the left side of the engine through the oil seal. Just wondering what could have made me overlook that.. 🍺🍺🍺
 

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Discussion Starter · #19 ·
That's what your clutch actuator actually pushes against, it's the bearing that stops the clutch rod from wearing out. Every clutch has something that does the same task. If it was a car that would be the clutch release or throw bearing.
That makes sense, I also figured it helps ease the engagement/disengagement function. On this particular one the ball is pressed against a crossbar and washer inside the inner clutch drum that releases the pressure plate
 
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