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So I got this gs 850 not running and went through and fully disassembled the carbs and cleaned and replaced everything. New intake boots and o- rings. New air box to carb boots. Bike didnt have stock air filter so I got a stock air box but doesn't have the filter installed at the moment as I don't have one yet. The bike fires up after several tries with the choke on but only runs with choke on. Occasional backfire occurs as well. Struggles to start back up again and only with choke on. The backfiring thing tells me timing may be off? Also, I have not done a valve adjustment yet and probably should be doing that asap. Any help or advice that you can lend me is very much appreciated as I have an idea why the bike isn't running great just need some advice and direction as to where to go with it. This is my first gs. Also, compression reading is 120 across the board which is on the low side. Thanks
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Problem may well be the missing air filter. Running on choke indicates lean, which indicates too much air to fuel, explained by missing air filter. Get the filter in then see how it runs. May still have problems, but that's step 1 IMO.
You could adjust valves while you wait for the air filter. -
+ 1 on the filter being part of your problem but you should do the valves first IMHO and also put in the filter to see what you have.Also, I have not done a valve adjustment yet and probably should be doing that asap.
Since your bike was a non runner most likely the PO did not ever do the valves and that is why it was not a runner. Did you bench sync the carbs after you cleaned them and are your mixture screws even?82 GS850L - The Original http://s224.photobucket.com/albums/d...ePics067-1.jpg
81 GS1000L - Brown County Hooligan http://s224.photobucket.com/albums/d...ivePics071.jpg
83 GS1100L - Super Slab Machine http://s224.photobucket.com/albums/d...t=DCP_1887.jpg
06 KLR650 - "The Clown Bike" :eek: http://s224.photobucket.com/albums/d...nt=SERally.jpg
AKA "Mr Awesome" ;)Comment
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There's no point in doing anything else to the operating conditions of the bike till you get an air filter.sigpic
82 GS850
78 GS1000
04 HD Fatboy
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As said it will never run good without the airfilterComment
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Actually got it fired up and running great with no choke but only on 2 cylinders. Only running on 3 and 4 right now which is weird because when I first started it it was only 1 and 2 that were firing. It revs great and decelerates great and idles great as is but only 3 and 4 firing. weird.Comment
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Do a compression check.
Adjust valves
Split and dip each carb body and only use Mikuni jets.1983 GS 1100E w/ 1230 kit, .340 lift Web Cams, Ape heavy duty valve springs, 83 1100 head with 1.5mm oversized SS intake valves, 1150 crank, Vance and Hines 1150 SuperHub, Star Racing high volume oil pump gears, 36mm carebs Dynojet stage 3 jet kit, Posplayr's SSPB, Progressive rear shocks and fork springs, Dyna 2000, Dynatek green coils and Vance & Hines 4-1 exhaust.
1985 GS1150ES stock with 85 Red E bodywork.
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Did a compression check. 120 on all four which is on the low side. What you think?Comment
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+1 get everything back to normal, then work from there, esp. with a missing air filter. Doing the valves while you wait for the filter is a great idea. Also, a bench sync will get you going, but is in no way a substitute for a true carb sync.Originally posted by Octain View PostComment
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120 is fine. Carry on1983 GS 1100E w/ 1230 kit, .340 lift Web Cams, Ape heavy duty valve springs, 83 1100 head with 1.5mm oversized SS intake valves, 1150 crank, Vance and Hines 1150 SuperHub, Star Racing high volume oil pump gears, 36mm carebs Dynojet stage 3 jet kit, Posplayr's SSPB, Progressive rear shocks and fork springs, Dyna 2000, Dynatek green coils and Vance & Hines 4-1 exhaust.
1985 GS1150ES stock with 85 Red E bodywork.
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thanks. i'll get the filter and valve cover gasket ordered and start tackling the valve adjustment.Comment
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Originally posted by C.V. View Post
And how do I do a true carb sync. Is there a website out there that explains it? thanks.Comment
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A Bench sync it taking a pin or wire, and making sure each butterfly is set pretty close to all the others. It will get them close enough so that one cylinder isn't pulling a ton more than the others. It's the "close enough for government work" that you do after tearing carbs apart before you even mount them to the bike. If you're good this will be very close, but it might not be.Originally posted by tipwise View Post
A "real" carb sync requires a special tool, a manometer that measures vacuum. There is a small screw on each intake on the head you may have noticed. You screw an adapter onto it, hook it to the gauge, and it tells you exactly how much vacuum is sucking at that intake, which is a measure of how much fuel and air is getting sucked into the engine. the gauge has 4 towers/columns in it. You adjust the carbs until they are all the same (or #2 carb slightly higher than the rest, have to look at the manual). It can be the difference between a bike running "ok", and running "great".
You can make a manometer for $20 that works ok (or so I have heard), or a nice one called a Carbtune is about $120.Comment
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Last edited by Larry D; 11-18-2009, 03:56 PM.Larry D
1980 GS450S
1981 GS450S
2003 Heritage SofttailComment
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carb question.
I also forgot to mention that on the two cylinders that are not firing there was something weird with the carbs. There is a clip thing that mounts near the needle seat that I assume is for float height and on 1 and 2 that is deteriorated and almost gone. I just left if for the time being but I may need to source some parts carbs to replace those. Anyone know what I'm talking about or know where to just get that piece?Comment
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