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1977 GS550 project

  • Thread starter Thread starter Toucan
  • Start date Start date
T

Toucan

Guest
Hi all,

Been lurking for awhile and reading lots of your projects so time to share my own. Bit of a back story, I sold first bike and all other toys 2 years ago to embark on an OE, lived in an apartment in London where I had no parking space let alone a garage, and have been dying to get into my next project ever since. Have always been into 70s stuff so was quite keen when I spied the 550 on the national buy/sell website back home. It fit the bill being an early model with wire wheels, twin front discs and a kickstart, too cool! I was still oversees at this point but thought I would take a gamble and bid sight unseen, given that cheap old bikes aren't as plentiful down here in New Zealand. I won the auction and got it shipped to my parents garage to await my return.

Original auction photo
1f125web.xgx.jpg


Fast forward a few months and I finally got to see it in the metal. It wasn't quite as nice as I was hoping, but on the other hand I had been craving something I could spend time tinkering with so I guess it will just keep me busy for longer. Somewhere in its past life it has had the back end cut off and the seat modified, which wasn't done as tidily as I'd like, the side cover clips are all broken, the wiring was a mess, and to top it all off, the whole thing has been sprayed black with little to no prep work, so I have paint flaking off here there and everywhere whenever I touch it.

First things first I went over the wiring and fixed numerous bad connections and melted wiring
rcgv2rgt.g1x.jpg


With a new battery, most things are working, still some trouble shooting to do here. Ripped the valve cover off and checked my clearances, my 0.04mm feeler gauge goes through but not my 0.09mm so I think they are good for now.

Put some gas in the tank and fired her up without too much trouble, she didn't want to rev nicely but idled long enough for me to put a multimeter on the and confirm it was charging. Took for a quick ride down the end of the road and back, man was she loud! Time to take off the exhaust wrap and see what was hiding...
v0v5gccd.fig.jpg


Many exhaust leaks! These aren't even all of them. I gave them a wire brush and took to a friends place to see if I could weld them up, but the holes just kept on getting bigger! I think this exhaust is past it, have enquired about a replacement Marving unit after reading various reviews, not cheap though once you include shipping!

Next up I wanted to get the carbs apart.
mpbzm5xd.utn.jpg


Gave them a bath in simple green and hot water to start with
zawaossp.baw.jpg


Had some trouble getting the main shaft out, was alot of grime stuck on it holding it in place, got there in the end
ey3k0wf2.yoh.jpg


Took note of jets and whatnot as I stripped them, all looks standard with #80 mains
pdccmkb3.xg2.jpg


Borrowed mums jewellery ultrasonic cleaner, splash of vinegar and simple green with hot water did a good job on the brass bits
3z3nghlk.hxp.jpg


Before & after, only 5mins to get them clean. I have a new set of orings waiting to be installed thanks to cycleorings.com
aajudoko.er4.jpg


As it sits now. Awaiting some new parts before I can begin reassembly, but lots of cleaning and polishing I can do in the meantime.
2w0bewif.hpx.jpg


Thanks for all the info on the forum, has made my work up until this point much easier!
Daniel
 
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Nice work so far! I'm doing the carbs on mine right now as well, looking forward to more updates. Cheers from another Dan with a '77 GS550.
 
Hello, I have the same, located in France! I am running "nothing" into the airbox and a free 4/1 exhaust. I am currently adjusting the main jets, because a lot of work to do with these modifications. Could you say what size of the main jets is on your bike now?
I am doing plug chops to be able to choose between 107.5 and 110....

best regards!
 
Just checking on your carb strip, because I can't see them in your photos, did you take out the secondary pilot jets?
 
You are right they are hiding in the photos but I did get them out with everything else. The only parts still on the carb bodies are the bowl gaskets which I am reluctant to remove because I'd likely damage them and I don't want to have to wait even longer for new overseas parts

Boris - main jets are standard size 80 and needle on middle position but as I mentioned it didn't run well when purchased so not the best baseline to go from!

Yesterday I have measured all the bolts and will get new stainless capscrews to replace them as a lot were stripped and hard to remove, I would be lost without the impact driver I've been using. Also found the typical layer of gunk under the sprocket cover and the front sprocket itself has about 2mm play in it, looks like it is missing a spacer or hasn't been tightened up, more investigation required...
0m3f1koz.wv1.jpg
 
ok, thanks!
if you want to keep the 4/1 and improve air admission, I should advise you to go for main jets between 102.5 and 107.5... :)
 
Changed focus last night and tried to use a fibreglass kit to repair the broken clips on both side covers. Had a bit of trouble with the epoxy so will need to go over them again and tidy them up plus add some more glass matt.
dzth0vzt.xda.jpg
 
Picked up a second hand SH775 that everyone seems to rave about, all the farming work it has done is bound to help my GS off roading ability right?
a2ksa0bd.3a2.jpg


Also grabbed a Dyna S while I was over in the UK, won't install until I've got it going okay on the points. Also I think it is for a Nippon Denso and I have Kokusan, or vice-versa, but I read somewhere I can just space the rotor and it will work?
4oyfosqd.n4g.jpg


Polished the cam end covers on the drill press
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Currently continuing to try clean the carb bodies, soaked them in gun wash then ultrasonic bath in simple green & hot water. Not coming up as good as I had hoped externally, I might do them one more time then call them good enough
pkqc55nf.r0m.jpg
 
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Time for an update. Carbs are back together again, went up to 85 on the mains, bench synced
hynnpvem.byp.jpg


Got it running with the dyna-s. Had to take 0.5mm off the top of the rotor to allow the mechanical advance to work, just used sand paper to get it down to size
dj0pysfu.ugf.jpg


And last but most excitingly, Marving exhaust arrived. Great look and sounds vastly better, fit is quite tight, number 3 exhaust port doesnt line up 100%. Just need to collect some new exhaust gaskets and some M8 studs to finish off the install. Here is a pic as it sits currently
nvurbwhh.qxq.jpg


Oh and I had the plugs out to clean them up and realised I have some 6's and 7's. Is it normal to have different heat ranges on an aircooled motor? I didn't take note of how they were before, but I put the hotter ones on the outside cylinders when I reinstalled them as I figure they get better cooling than the middle two
 
^ Don't remind me Charlie! Still steaming about the suprise customs bill I had to pay before they were released to me.

Ps. thanks :)
 
^ Don't remind me Charlie! Still steaming about the suprise customs bill I had to pay before they were released to me.

Ps. thanks :)

Ouch! I hadn't considered any customs charges, just shipping.
 
Nice looking GS. Looking forward to following along on your project.
 
Series reg/rec is in. Waiting to do a few more rides and make sure everything is fine before covering the loom. Added some fuses as there were none when I got the bike.
wlsuchry.kbr.jpg


Had some issues with it running on 3, so have had the coils off and cleaned up some more dodgy wiring there, all back together and running on all 4 again.

Petcock rebuilt and refitted with a new gasket. Extended the fuel and vac lines to the tank as they were barely long enough before, lots easier to get the tank on and off now.

Starting and riding quite nicely given I just threw the carbs together. The hard part now to fine tune them, fun fun!
 
Plug chops!
md1hyzqc.gne.jpg


I just checked the manual and realised neither of these are the correct plug so I think I will get 4 new matching plugs before I start making any adjustments :!:
 
Been doing odds and ends, not as often as I should. Carbs have been off and on a few times thanks to number 2 overflowing. Then waiting for new gaskets as the ones I got shrunk! Have finished putting a new needle valve and seat into number 2 carb and resetting the float only to find it is still leaking fuel, grrrr!

zpThqMV.jpg


Also have been reworking the rear end to incorporate the original tail fairing. Purests close your eyes.
Am happy with the tail mounting for now, the seat pan took a bit of cutting and reshaping, just need to shape the foam and make up a cover to finish it off.

BE4WY4D.jpg
 
Despite the normal tuning and wiring ups and downs you are going through sorting this thing out you have in this short build thread shown what it takes to get a gs running.
A lot of new forum members should take note of the proper and methodical way you approached getting it running.
Everybody wants to take shortcuts and just spray a can or carb cleaner and turn some mixture screws and expect the bike to run.
Keep up the good work.
It's starting to look good too....
 
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