Can you pull the carbs and take measurements and note any part numbers?
Thegsresources forum can also be of assistance.
This is a discussion on 1980 GS1000ST resurection within the Project Builds forums, part of the Caferacer.net Forums category; Hi All, I am bringing an older Zuki back to life. My father parked it in 1985 with 5000 miles on it and it sat ...
I am bringing an older Zuki back to life. My father parked it in 1985 with 5000 miles on it and it sat for 35 years i his garage. The carbs don't match those in the manual nor most pictures on the internet but he is the original owner and I am positive the carbs a have not been replaced. It was purchased in Sunnyvale Cali, and the carbs have large square tops (CV?) and not the small rectangular tops in most pics. Is is a Cali thing, a factory prototype bike, or something else?
there will be a suzuki model code on the carb body
that is if its an oem carb set
there is also numbering at the float bowl or rather where the float bowl plants against the carb body
on the side of carb should be visible without yanking them off
i cant remember if the vmodel code is part of the numbering but i dont think so it will be just the model or type in mikuni code
the goddam model codes can be very faint and often are found on the side of body at the spigot just before it enters rubber boots at intake port
beyond useing a magnifying glass i have found that a normal point and shoot digi camera set on macro and flash turned off gives the best chance of reading any faint numbers
you just need hold the camera steady and have normal indoors ambient light but not shadowed
i went to partzilla and 491 is in the [part numbers of the 1980 gs1000s and they are cv carbs
nice thing about many parts house online IPB's aka illustrated parts breakdown.when you click on a part in the list on the ipb page a pop up page comnes on with a feature that lists all models using same part
ok here is the partzilla page ipb on carbs
and here is a link to that csmnl outfit and suzuiki frequently asked questions which contains scrolliong down a bit suzuki model codes and 491 is indeed gs1000 they dont show the s as in gs1000s but show 2 gs1000 model codes
Last edited by XB33BSA; 03-16-2019 at 01:41 AM.
you have enough clues now to answer your question as to why you have cv and not slide valve carbs
Manufacturers moved to CV carbs to comply with emissions requirements. Your bike was bought in California which is a state that takes air pollution seriously, so no real surprise there, motorcycles imported into California often have the latest and greatest parts and assemblies to pass emission testing. The bike might also feature things like a PCV (Positive Crankcase Ventilation) system to catch and recirculate unburnt fuel that blows by the piston rings. Usually those assemblies are described in the owner or service manuals as a addendum indicating 'California model' or something similar. Up here in Canada we are too cheap to do our own testing and historically we just adopt the California emission standards.
Extremely unlikely that Suzuki of Japan would ever put prototype bikes into a foreign market when they can prototype bikes for their domestic market, that just wouldn't make good business sense and Japan also takes air pollution very seriously, Tokyo air is just as thick with pollution as L.A. and European emission standards are even more stringent then California. That's why fuel injection models showed up as standard equipment in Europe before it happened here.
If your carbs do have issues from sitting you can almost be guaranteed the problems will all be in the bottom half of the carburetors, that is where the old fuel, dirt and water accumulates, the top half of the carb body only contains air. I bet there is nothing wrong with your carbs original parts that a cleaning wouldn't fix and no way would I worry about sourcing replacement parts until I serviced them at least once.
Thanks all for the valuable input!
I plan to pull the carb bank and start the rebuild this weekend. I oiled the cylendars, change the oil and turned it over manually with the plugs out for a while, then via starter to pre lube before putting in plugs and the test fire. Only ran it a couple times for a minute or so to get the oil moving and "freshen up" the internal seals and gaskets. The bike ran on full choke on 1, 2, & 4. So I know all pilot jets are clogged and #3 main jet must be clogged or the float stuck and not letting any fuel in. No over flow discharge so that is a good sign. Brakes are all crusted up so that will be the next step once it is purring. Tank was totally munged up so after trying to clean it I had it cleaned and lined professionally. They did a great job and did not add too many new "character marks" to the OEM paint.
beautiful bike you are very fortunate to have it
1979 had slide valve carbs
the trick to yanking the carbs is use lots of wd40 to wet the airbox rbber carb bell mouth connectors and push them inside the airbox as you manipulate them from the way they are fit to the box