It's 1979

[Grimly]

Yesterday, both carbs stripped, cleaned and rebuilt, and now have the internal details of main jetting. Interestingly, the float level on one side was a couple of mm different from the other carb. I also found the Mikuni float level illustration that I could find related to an older one, so simply had to make an assumption about the spacing, reasoning the datum point wouldn't be totally, wildly different from what both carbs presented me with. They're now the same anyway, and I'll check the running plug colour. I see the main needles were set at a middling position, so there's leeway there if needed.
Also painted a side panel - there's a mixed pair; one of them is the OE Special panel, and the other one is from a Standard. Luckily, nobody sees both sides at once. I'll pick up a matching one of either type to make a pair.
Paint will be satin black - that is matt black with a satin clear coat, perhaps with a top half of satin dark green and a copper coachline between. I'll see how it looks on a smaller scale before committing myself to the whole thing.

[Grimly]

Mikunis back on and roughly clankerated (slides clank down simultaneously) enough to start. The standby battery is mullered so the fire wouldn't light, but a fresh battery sorted that and all the kicking over with the dead one certainly brought a willingness to wake up.
Amusingly, it started fine with no choke, and the old coal-fired locomotive smell re-inforced my suspicion that it's simply far too rich - confirmed by the gust of black soot when the throttle is blipped.
However, when warmed up it settled down nicely to a mild tickover at 800rpm, both cylinders pulling their weight, if not quite evenly. Exhaust pipe IR readings reveal the LH cylinder is over-fuelled or the RH one under-fuelled - a difference of 30degC. I don't trust this IR thermometer to give anywhere near accurate readings in that range, as it's way over what it's supposed to do, but the difference is repeatable, so likely reliable as an indicator.
Tomorrow, more fiddling.

[Grimly]

More fiddling.
Did the valve clearances yesterday - they were ok, with one exhaust and one inlet slightly slack but nothing worth noting. Of more annoyance was the stripped thread into the alloy of the head where one of the studs to hold on the left inlet inspection cap goes. Ordered up a set of M6 helicoils to fix that and the sump plate properly.

The Mikuni VM34s are handed L-R versions and so far as I can see, the only difference between them is the side the air adjuster screw is on. Given that, why on Earth did the PO or someone mount the carbs with the screws facing each other, on the insides?
Made it nearly impossible to adjust the slide bottoming setting.
I swapped them over so the screws are easily accessible from outside, and the idle air/fuel mix on the (now left) carb is still reachable with a long screwdriver from the RH side.

Today, temporarily fitted the stripped stud with AbroSteel (which had set rock-hard from yesterday) and installed the valve adjuster cap, then set about starting it and warming it up for a timing check.
Intrigued to find the Boyer Digital ignitor has inbuilt advance, so the bob-weights have long since been binned and I hope I never need to find another set at short notice. Anyway, a couple of priming prods on the kick lever, switch it on and it starts nicely from cold now, even with the carbs being disturbed greatly when swapped around. Warmed it up, set the carbs again (vac gauges and colourtune) and checked the sparks - spot on, as expected.
Been looking at the possibility of fitting a 17" rear wheel to it, with the intention of only needing to have one size of rear tyre for all three bikes and discovered the GS500E wheel is a good fit - just have to find a smaller sprocket for it.

[spyug]

Oh man these are great little bikes and I kick myself everyday for letting mine go. Stock 78 that with too much cash thrown at it became a street tracker.

A real hoot of a bike :
resample2.jpg

Easy to spend money on these with tons of available parts and mods. I had this bike 6 or more years ago and a lot of the stuff came from Mikes. I found them to be fine to deal with and parts then were of good quality I thought.

That bike had little in the way of engine upgrade other than jetting and pods but most of the money went to suspension including progressive springs with cartridge emulators in the front and ZX 1100 gas shocks in the rear. Front wheel was converted to dual disk with stainless steel brake lines and upgraded master. Hoop style fork brace for stability up front. In the rear end a similar size wheel to the front from a 500 Yammie as I recall along with 530 chain and aluminum cog. sorry I can't recall the toothing. The swingarm was a braced rectangular profile unit from an unknown bike, possibly an early Yammie sportbike. Fresh rubber too, of course.

The seat was handbuilt by yours truly and was actually the cause of me selling the bike. Fiberglass over foam construction and hard as a board even with the pad. I ended up squishing my left sciatic nerve in my ass and losing all feeling and some control of my left leg. That took me out of riding for over a year but on the upside caused me to find GSs. Fell in love with the whale of a seat on the 83 750 I snagged and brought me to this nut house.

But now, as I said, I really truly wish I had kept that bike. Oh well so many bikes so little time as they say.

I am sure you have found it but if not the XS 650 Garage is the XS equivalent of the GSR. http://xs650temp.proboards.com/ Some super great guys and all the knowledge you will ever need.

Enjoy the hell out of that bike, I'll be following your progress you lucky sod!

Slainte

[Grimly]

Cheers, Spyug - that's a cracking looking job you did with that.
Mine is more of a rescue dog (mind you, I think a lot of them are) being re-homed and turned into a back-road scratcher.
Today I scored a Kawasaki ZRX400 seat, which is on its way to me from a local-ish breaker via ebay. I think I'll be comfortable on that, as it's quite well padded and like you, have the odd sciatica problem, so am sensitive to bad seating. As soon as I sat on the Special seat, I knew I couldn't ride it like that - old collapsed foam and wrecked cover made a rebuild necessary anyway, so I was looking for another solution.
The nose of the Kwak seat looks as if it perfectly matches the rear of the XS400 tank I'll be using, and by shortening the seat I can make the bike totally solo and free up space behind me for occasional cargo - the idea being to keep all weight in the wheelbase and not have a rack or box hanging off the back.
Every time I pick the Yam up to move it around, it feels just so light compared to the GS and I want to keep that feeling on the road, hence the cut-down, slim-down approach.
Got the XS400 tank de-rusted today by sloshing some 20% phosphoric acid solution around in it and leaving it overnight. Rubbed it down beforehand and it came up well. I think it will look fine in satin black with black highlights.
I now have a pair of Standard/Roadster side panels to match the more angular lines of the tank - the bike came to me with one Special panel and one Standard.

[Grimly]

Just had a quick fiddle underneath after seeing this chart over on XS650.com...
XS 650 Dome Nuts Copper Washers for bottom case.jpg
One of the niggling oil leaks was caused by the two middle dome nuts having no copper crush washers at all - sheesh, some people.
The other one is where a pair of stripped threads exist on the oil pan plate - there's enough good thread to just grip and with the aid of some Hylomar on the bolt heads and washers, it will do for now. I intend to mod a spare plate to carry an external filter, so once I do that and swap it out, I'll repair the threads then.

[Grimly]

Trial fitting the XS400 tank in conjunction with the ZRX400 seat, reveals a pleasing combo. There's a slight gap, but when the fixing lugs of the tank and seat are sorted properly, they'll exist quite well together.
Don't think I'll bother messing around with hinges - under the tank securing bracket there's a nice space for a tongue from the seat to go under, and I can devise a QR latch (or two) for the rear. The seat sits perfectly on the frame rails, as if made for them. With the addition of some rubber bumpers, it will work well.
DSC_0007.jpg

[Grimly]

Re-tackled the brakes again yesterday and today. I'd put the calipers back on last time only to see how bad they were and to use the handlebar lever to pop the pistons if necessary. Turned out it was very necessary.
The LH caliper popped apart easily enough, and revealed a piston that was very slightly pitted, but cleaned up well enough with a touch of emery and wire wheel. I'll put that on the list for replacement; even though it's gone back on the bike, I would like to know items like that are as they should be. That caliper struck me as having been rebuilt / renewed at some point - the seal was perfect, as was the dust boot. Given the bike is 36 years old, it's likely that someone did a brake rebuild before I got it.
The second piston took some moving - the master cylinder wasn't shifting it, and the application of a blowtorch to the caliper body had it moving eventually under pressure. In spite of this being much more stuck, the piston was entirely unmarked and doesn't need replaced. The seal is totally gubbered though. So, that's a new piston and a seal kit needed.

[Grimly]

XS400 tank now equipped with two rear-ward fuel outlets to utilise traditional on/off/res on the left and off/res on the right, which rather cunningly gives me a reserve and a deadly-serious-last-gasp reserve. Just got to blank off the original petcock hole with a plate.

[spyug]

Well I've been away for a year or so but back in the game again and glad to see you are making progress on the XS. I'm getting stuck in to a free to me CB 650 and am just putting the carbs back together in hope of firing up in the next day or so. Everytime I look at my CB 650 I think of the XS and kick myself one more time.

I am not planning on keeping but just tarting it up for a flip in the spring, but I find myself thinking about the mods I could make if I were to keep it. But I won't.

I'm looking forward to seeing how yours turns out so keep the pics and story coming.

Slainte.

[Grimly]

Made the blanking plate from some scrap 3/8" (10mm) mild steel plate, with enough left over to make a couple of adapter plates for the GSs when I get around to replacing the petcocks on them. The older GS petcock responded well to a replacement rubber multi-holed selection washer and some re-facing of the mating surfaces, but the newer one still has a tendency to leak very slightly, so might need total replacement.
The front brake seals arrived and are now in place with brakes bled up fine. I think I'll fit a Honda Deauville master cylinder, as I like the feel of them and they have an adjustable lever span, but that can wait.

[Grimly]

Noticed a couple of weeks ago that one of the Hagon shocks had blown its guts, so was waiting on some new shock bushes to allow me to fit the old GS shocks to the XS. They arrived, that's done. I don't know whether the Hagons were the right size, but the GS ones are an inch longer at 13". Seems to make no difference to the ride height anyway, as these old original GS shocks feel more softly sprung than the Hagons. They'll do for now, just to get it back on the road. Given that I'd bought the GS shocks as used-but-good just to keep the Suzuki going when the Killer Pothole blew the air shocks on that, I wasn't expecting too much of them, but they worked well enough, if not fantastic. Amusingly, I only recently re-discovered the damping adjustment on them. I'd totally forgotten about that, since it's been so long since my last original set of GS shocks.
Here's a tip for anyone with OEM GS shocks - check under the rubber cap at the top for corrosion - my first set rotted away completely there, due to road salt being trapped underneath.

[Grimly]

Had got the XS400 tank back weeks ago from a local who brazed a couple of fuel tap outlets onto it. When I went to pick it up he told me he'd soldered them on. Ok, that would work, if the solder is good and properly done.
Only, it's not.
One of the fittings damn near came completely out of the tank at the slightest nudge today when I was painting it.
Can just imagine that happening when going along the road, so glad it happened now, before there was any fuel in it and it makes it easy to rectify.
Of course, it will wreck the paint I've now done, but it's not showroom, so I'm not too bothered about that. A few quick repair blasts will fix it.

Oh well, re-instate the Special tank for now.

[Grimly]

Great golloping blobs of Fry's Lead-Free solder fixed that up, good. Not pretty, but strong enough. Installed the taps - LH side, an On/Off/Res tap (must check the flow rate on that, as the main inlet pipe on it seems a bit thin) and the RH tap is a Reserve-only genuine BAP tap, as used to be fitted to many older Brit bikes. I think I'll get a BAP Main tap for the LH side and do away with niggling worry about the fuel supply. I'd hate for it to run into lean-out trouble later on, when it could be avoided.

My intention was to have On/Off/Res on the left and another Res on the right, but to make sure of sufficient fuel flow I'll forego that, and just have one reserve.

[Grimly]

Uncertainty and doubt about flow-rate and demand exceeding supply made me re-instate the Special tank, which looks much better than it did, now it's got a fresh coat of black paint. I still don't like the shape of it, but it will do for now. Stripped, examined and re-built the vacuum taps and surprisingly they're perfectly fine now. The slight leakage they were showing was probably due to them sitting for years dried out.