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Hi everyone, I'm a new member and need some help figuring out the cause of a problem. The bike is a GS1000S and in cold starting it struggles to start and only seems to start on two cylinders. Once warmed up the engine runs normally although cylinders 1 and 4 remain colder than the others. In cold weather it is the cylinders that struggle to start. Is it the 1/4 coil? Will it be the high voltage cables? who can help me? thank you all.
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Welcome
Start w/ the top 10 Newbie mistakes thread linked in my signature.
Also see the VM Carb rebuild tutorial found on BikeCliff's Website (link in sig) look at top of right column below the wiring diagrams.
When did you last adjust shims/valve clearance?
Rich
1982 GS 750TZ
2015 Triumph Tiger 1200
BikeCliff's / Charging System Sorted / Posting Pics
Destroy-Rebuild 750T/ Destroy-Rebuild part deux -
Hi, that the bike has 20K km and, to my knowledge has never been checked for valve registration. Don't you think it's an electrical problem?Comment
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I can only guess. But the fact that it does eventually fire on all 4 leads me to believe that your problem is more fuel delivery related. Tight valves can lead to poor running and eventual damage, not sure if it would cause your cold start issue. My first look would be at air leaks between carbs and engine, then fuel delivery/clean carbs. But I'm certainly not an expert.Rich
1982 GS 750TZ
2015 Triumph Tiger 1200
BikeCliff's / Charging System Sorted / Posting Pics
Destroy-Rebuild 750T/ Destroy-Rebuild part deuxComment
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No personal knowledge on the two valve engines, but they are said to be hard to cold start when the valve clearance is too tight. If you've never checked them don't assume a previous owner has.
Great looking cycle by the way.sigpic
When consulting the magic 8 ball for advice, one must first ask it "will your answers be accurate?"
Glen
-85 1150 es - Plus size supermodel.
-Rusty old scooter.
Other things I like to photograph.....instagram.com/gs_junkie
https://www.instagram.com/glen_brenner/
https://www.flickr.com/photos/152267...7713345317771/Comment
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It may be a stupid question, but do you turn your petcock to the "Prime" position when you try to start it up? After I got my S, I went through the same problem before someone told me about the petcock position. It, too, would be very hard to start, and when it did, it was only 2 cylinders until it got the fuel it needed.Last edited by nvr2old; 04-11-2022, 06:40 PM.1979 GS1000S,
1982 Honda CX500 Turbo, 1982 Honda MB5 w/CR80 motor, 1977 Honda "nekid" Goldwing, 1976 Honda CB550F cafe', 1972 Honda XL250 cafe'Comment
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Originally posted by nvr2old View Post
no such thing as a stupid question.
BTW... Good looking GS
sigpic
1980 GS750LComment
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I think it could be useful, however the problem with the petcock is the type that doesn't have the opening lever and, to put it in prime you need a screwdriver.Comment
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This is a petcock of my GS 1000 S.You do not have permission to view this gallery.
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I'm certainly not an authority, but that petcock looks like it needs to be thrown away. New ones are available, a bit pricey, but a new one would eliminate the possibility of that being your problem, or at least takes away the need to use a screwdriver to turn it. I can only imagine what a pain it is to do that. These engines require a good shot of fuel to fill the carb bowls and get them to fire up. Prime, start the engine, and then return it to the On position once it's running.Last edited by nvr2old; 04-12-2022, 05:25 PM.1979 GS1000S,
1982 Honda CX500 Turbo, 1982 Honda MB5 w/CR80 motor, 1977 Honda "nekid" Goldwing, 1976 Honda CB550F cafe', 1972 Honda XL250 cafe'Comment
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Got to be in the running for one of the stupidest things Suzuki ever did... doesn't even have a RES... Thank goodness "80" was the only yr. they used it.1983 GS1100E, 1983 CB1100F, 1991 GSX1100G, 1996 Kaw. ZL600 Eliminator, 1999 Bandit 1200S, 2005 Bandit 1200S, 2000 Kaw. ZRX 1100Comment
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Your petcock needs to go …….first thing that I’d suspect . Get a new one and understand how it’s designed to work,especially in prime spot. This Florida guy sells them for about $45 ….you should be able to find the equivalent in your area. Skip trying to repair your old one!
1981 gs650L
"We are all born ignorant, but you have to work hard to stay stupid" Ben FranklinComment
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Shoot, that one, K&L brand, says it has ON / OFF / RES / PRI. Huge improvement over OEM.1983 GS1100E, 1983 CB1100F, 1991 GSX1100G, 1996 Kaw. ZL600 Eliminator, 1999 Bandit 1200S, 2005 Bandit 1200S, 2000 Kaw. ZRX 1100Comment
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Yes, I actually replaced that petcock because it was damaged. I did however repurchase the same model because that's how it comes out of the factory. The model with the lever was way too expensive. Now I'll see if I can check the synchronization of the carburetors to see if they open in tune. Anyway thanks for the advice. I will update on the outcome.Comment
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Hi all, I wanted to update you on the progress in eliminating the problem of limp engine operation on cold start and first few metres of run. The carburettors were completely reassembled, and were in perfect clean condition; with the help of a carburettorist we subjected them to a sort of vacuum to check that all the internal passages were free and clean and indeed they were. The float level was 24mm for all of them. After that we subjected the bike to synchronisation with the instrument carburettor. I can therefore say that the problem does not stem from the carburettors or from the petcock which is new. However, the problem disappears almost completely when the engine reaches operating temperature. The spark plugs spark is strong for all cylinders. The compression tested with the instrument is about 10Kg/cm2 for all cylinders. At this point it remains to adjust the valves, are they tight? or wide? Are these symptoms of failed valve adjustment? Sorry for my english by Deepl.
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