"...by his own account, was moved from his home to the place I bought it under it's own power."

Have you actually seen it running? (I'm guessing no.)

No, but prior to the sale, we (Seller and I) tried to start her up; but there wasn't more than a few coughs and around 5secs of running. I didn't want to stress the poor thing too much nor fry the starter motor, so I called it off after a few tries. The purported time/distance travelled amounts to around three minutes.

Since she turns and fires, I don't think it makes a big difference wether he drove it this short distance, or not? (I also quite don't believe he did).

I'm strongly suspecting pilot jets clogged up by residue of evaporated gasoline.

That fairing is funky cool. Good luck with the project.

+1 on the fairing, 550's are great bikes with a little....... hammering.

Great bike. That's a good looking fairing. Nice find.

Made some progress this weekend (Pictures will follow). Drained the tank, took off the carburetors (#$%^#$ this airbox, man!), removed instrument panel in order to swap the tach onto "Red"
later on.

Took the bowl off carb #1, removed plunger with needle (not sure if it's the correct term) and put everything into the ultrasonic bath for a first go. Didn't want to disturb any jets, so I left them as is.

I'd really like to get rid of this mighty stupidly built airbox, to ease maintenance down the road. When looking for carb gaskets on Z1, I noticed that they carry reasonably priced pod filters.
If I were to put them on; I guess would I need new jets?

There is a trick to getting the carbs on the 550 in and out. Remove the inner fender, the battery box, anything else that prevents the airbox from moving aft. If you remove everything there is enough space. You live in Switzerland, I assume you ride in mountains. I think your roads go fairly high, and you probably also need it to run well at or near sea level. The stock airbox will work a lot better than pods will for riding at a range of elevations. Not as well as the later CV carbs, but a whole lot better than pods. I live in the rockies, our roads are from 14,000' to about 2,000'. Running pods I can tune for the elevation of my house, 5,800' or so. It's running rich by 8,000', by 9,000 it's annoying to ride, needing to feather the throttle, keep the RPMs up very very high, etc. I can't ride to the lower parts of Colorado without rejecting, it's too lean. With the stock airbox, I can ride with sea level jetting at higher elevations, it runs a lot better at all of the different elevations. Not well enough for me to keep the VM carbs, but well enough to enjoy riding it until I do switch to CVs.
With CVs and the original airbox it will run just fine with stock sea level jetting at 14,000'. Slightly less powerful, but still runs smoothly with good throttle response. I'm switching to an all CV fleet, or fuel injection.

If you do decide to run pods, get good ones, the crappy ones don't flow much air, don't fiter much of anything, and are damned near impossible to tune correctly.

Thanks for the trick - I almost did like you said, with the exception of the inner fender. I did ponder to do it; but I currently have the bike in a shared space and didn't want to make too much of a mess, and be quick about it (Though I'm not sure I achieved the latter goal ).

Re. the carbs; I live in the midlands, elevations where I primarily ride go from around 400m (~1300ft) to around 800m (~2600ft), sounds like I could tune pods+VMs to this; at least on one of the bikes.

I didn't realize that the VM's don't compensate for altitude, and I would like to be able to go on longer tours later on; where I'll go above 10k ft. Looks like I've got to hunt for a set of CV's if I want to get rid of the airbox on the bike I'm going to run mountainside.

( Side note; Fuel Injection on a 70s bike? From a cursory google search I now know that retrotfit kits do exist (the times we live in!); not sure how they're gonna fit on a 550. )

Alright, some pictures as promised.

Warning: They're 4K. They should be automatically scaled to your browser's viewport, so in theory this should result in nice crisp images on a modern
browser, more so on high ppi displays (most mobile devices, most modern and - IMHO - all future desktops).

So if you're reading this on a potato or a slow line, let me know; I can switch to thumbnails+links instead.

First, remove seat, tank, and parts of the fairing - but since I had no possibility to lift the bike, I couldn't take it off completely. Not really necessary though.


After some wiggling and strong words; the carburetors got finally loose:


Intakes looks okay; methinks?





And it looks like #2 and #3 were leaking; note the staining on the bowls. But from what I saw on this forum; they're not too bad:


Had to dremel washer to get a stuck screw out:


But yeah; gasoline was drying out in there.
This is what I encountered in Carb #1:

Yew:


Gross!


Clogged jets:


Off into the ultrasonic bath they go:


As you can see, I didn't take out the jets. I don't feel confident enough to take the apart and get them back together right; and I reason the ultrasonic should reach in there. But feel free to convince me otherwise...

The ultrasonic bath I'm using has 250 Watts of ultrasonic power and a capacity of 4 litres. I'm using demineralized water with one or two drops of dish soap.
Real distilled water is too expensive and simply unnecessary for this application. If you're in a pinch, you can use tap water; but note that due the nature of the process you may get calcium staining on the aluminium body and the bath itself.

I set the bath temperature to around 40°C. I don't have a lot of the water on hand; and don't want to boil it all off – carb #1 had to stay around two hours in there (The ultrasonic excitement lowers the boiling point of the water). The dish soap is used to lower the water's surface tension; this helps the process greatly. Also; it'll bind all this dirt.

It's fascinating to watch the gunk be destroyed (but you need earplugs if you want watch the bath for more than a few minutes, resonances reach down to audible frequencies and hurt). This is carb #1:



As I'm writing this; carb #2 has entered the bath, and is currently into the second hour of sonic bombardment. I suppose the jets are free by now and first hour would've been sufficient; since after a brief check any remaining dirt can be just rubbed off. But I'm lazy and writing this post; so why not leaving it in for a bit more?

Next, I need to order some carb gaskets and replacement screws; as I broke one of the intake boots and the one I described above.

Oh yeah; intake boots seem to be okay. Wee bit stiff; but malleable. I couldn't see any cracks as well.


I'm not sure wether I need to replace the intake O-Rings:

They look more like square rings than O-rings - I'd replace them.

Not sure if you've done the carbs on this bike? If not, order a set of carb O-rings from Robert Barr, and get the intake O-rings at the same time. Very cheap, Robert does a very quick turnaround, and international shipping on small items like that is still cheap.

Plus one on the o rings.

And I would take out the jets. They're easy enough to get out as long as you use the right size screwdriver and especially with the 550 pilot system having 2 jets in series I wouldn't want to risk putting the carbs back on unless I could see that they were squeaky clean. Don't forget also the fuel and air screws - you'll need to check the former to make sure nobody busted the tips off.

agree on the orings, and on ordering from Robert Barr at http://cycleorings.com/ Just got some for my 1980 GS550E from him. Fast shipping, and cheap (price, not quality)

Yup, the rings will be replaced, and most likely I'll order from Rob.

Pictures from further progress will follow soon.