Carbs: cleaner in the gas, or take them apart?

S

serena.

New member
Hi all!

I just got an '85 GS700 that's been sitting for over a year. I dumped the gas that was in the tank and replaced it with fresh high octane. A couple of questions: should I go ahead and tear the carbs apart and clean them (something I've never done on a bike), or should I just try running a little cleaner through them, let them sit a night and try in the morning. So far I've put a new battery in and though it turns over just fine, no fire. Before it was stored it ran fine so . . well . . suggestions?

Ken
 
Definately run some cleaner through the fuel system, and if you use Seafoam, run some directly through the throttle body per the instructions. There's no reason to take them apart if that does the job.
 
:plus1:

First you need to determine if you have a fuel problem or a spark problem.
One way to do that is take air cleaner off. Squirt a little gas or starter fluid (careful, VERY explosive stuff) directly into the carb throat(s); choke open. Then crank it over. If you get a sputter out of it that way, then it is likely you do have a fuel problem.
 
I don't have any starter fluid so I'll try squirting some gas into the carbs. (can't get to town till later) Thanks! My buddy suggested that I pull a plug and check for spark, and also to see if I smell gas in the cylinder. I might try that if I can't get a sputter out of it. Also, I do have some Seafoam in the gas at the recommended cleaning ratio of 2oz. per gallon. Thanks again!
 
Ok. Got some starter fluid, sprayed it into the airbox and tried it. It sputtered, once. Tried again with same results but this time I kept cranking and it started trying - sputtering on its own - and after a few more tries it almost most ran. Then I noticed a 6 inch pool dripping from underneath. At first I thought it was gas but on looking closer found it was coming from a hose hanging from the airbox. Also, it smelled pretty potent for gasoline. Maybe it was starter fluid gathering in the bottom of the airbox? I only shot it in for the 2 - 3 seconds recommended on the can, and I did that about three times, trying to start it after each squirt. Could it just be hitting the screen and flowing down to the drain hose instead of going all into the carbs? Anyway, I am encouraged by what it did do; now I know it's got spark and was at least trying to run.
 
Yeah, you were probably spraying enough that it condensed and ran off. It doesn't take much. You've narrowed it down to a fuel problem, anyway.
 
Maybe....probably. The 2-3 seconds is the recommendation for a CAR, which usually has a much larger air cleaner, carb and displacement. If you need to do it again, keep it to 1 sec or less. If it was ether, it would disappear MUCH quicker than gas.

And before you go tearing the carbs apart, do you know where the drain screws are on the carb? Next think I'd do is set petcock to PRIme, put a can (or something) under the drain nipple or hose and open the drain screw. Let a couple of ounces run through. Close drain and let sit overnight. (All this considering that you already have SeaFoam in the gas).

This will also prove that gas is (or is not) getting to the carbs.

Now a personal opinion:
I know that Seafoam, Techron and Berryman's come highly rated for routine cleaning and minor pluggage but.......I've tried a couple of them on serious carb varnish and wasn't impressed. Seems like I always end up going back to the original Gumout for serious cleaning. Just MHO.
 
When I took he tank off to locate the "leak" I noticed that the fuel line was not full of gas. So could the petcock be clogged? I poured a little (maybe 2 cc) Seafoam right in the line and turned it over to get it into the carbs. I'll try running some of gas through as you suggest. It's a GS700 so there are 4 carbs. I'll try to figure a way to catch gas coming out of the drains, maybe a little funnel or something. There's not a lot of room beneath them. If Gumout works a lot better I might get a can, but I won't get back to town before Monday so I'll do with what I've got for now. ~Thanks a million!
 
More likely that the screens inside the tank, where the pickup tubes are, at the top of the petcock might be clogged.......or the actual pickup tube might be corroded shut BUT if the gas flows good through all 4 carbs then that's not the problem.

For draining the gas, a section of clear plastic tubing works good, at least 2 feet long so you can put it in a bucket or some such. If you guess at the size correctly it will slip on the drain nipple snugly.

If the fuel is flowing good to the carb bowls, you might want to consider an inline filter and just not worry too much about what is floating around in that tank. :roll: After you get it running, that is.
 
I don't think there's stuff floating in the tank - minimal at most. When I dumped it out I didn't see anything. But hey, who knows. I couldn't get every drop out so I guess there could still be some kind of gunk in it.

I took the petcock off to check it out. The screen and everything all look fine, but when I put it in the PRIME position I can barely blow through it. I took it apart and it looks ok - no blockage that I can see.

Question: with the tank off and the petcock set to PRIME how fast should the gas be coming out? Dripping? A stream?
 
Well that doesn't sound right to me either BUT.........



I would think it should be a steady stream, small maybe but steady.
I definitely think it should do more than drip.
 
I took a drain screw out of one of the carbs to check it out (no nipples, just screws). The gas that came out, well I don't know if it was the mixture of Seafoam & gas or if it was old rancid stuff but it smelled kind of strange. Shouldn't be old, but I still can't tell if a reasonable amount is getting through the petcock.

My stepson owned the bike before it was sold to the guy I bought it from and he cleaned the carbs on it. Ran fine for him. Maybe I can get him to look at it and give me some pointers, but I'll have to use a crowbar to get him out here :^)

Thanks again!
 
Hi all!
Well, I got the carbs off and cleaned out the junk in them. There was some goop here and there and the bowls had this yellow stuff hardened onto the bottoms. I scrubbed it off with carb cleaner and scotch brite and squirted carb cleaner through all the holes, they seemed to be clear, then put them back together. Had to use a shoe horn and a sledge hammer ;^) to get them back onto the bike but they're there now. Also, the petcock works fine now. Maybe soaking with Seafom helped. On PRIME it has a small stream coming out which looks good to me.

Anyway, it still won't start. Again; a little starter fluid, just a tiny shot, and it tries to run for a couple of seconds. So I have 2 questions:

1 - How long should I leave the petcock on PRIME? Seconds? A minute or so? Ten minutes?

2 - Does anyone know what size of plug wrench I need for this bike? (GS700) I found one in a drawer (for a car, I'm sure) but it's way too big and I'd like to make sure the plugs aren't fouled.

Thanks!
~Ken
 
Assuming that the floats and needle valves are working properly, you could leave it on prime forever.........but that is NOT recommended.

With completely dry carbs, it might take a few minutes to get all the air bubbles out of the carbs; rocking the bike from side to side a couple of times might help.

You are using some choke when trying to start, aren't you?
Fresh gas or the stuff with Seafoam in it?

another Ken!
 
I've got the stuff with Seafoam in it. It was fresh when I put the Seafoam in a few days ago so I thought it would be alright. Should I add fresh? Or replace what's in there?

As far as PRIME goes, I thought the float needles should stop fuel from coming in once the bowls were full, but the manual and all the resources I've read on the web say that fuel could overflow into the crankcase if left in the PRIME position.

Anyway, the bowls are full now but it still won't start and idle. It sputters with the choke on and with a tiny shot of starter fluid it starts right up . . for a couple of seconds. I'm still wondering if some of the plugs could be fouled (hoping), but I've got to get to town and get a plug wrench that fits - I don't have deep sockets. (or deep pockets) :^)

Thanks Ken,
~Ken
 
It should be OK.......but for $6 or so, I think I'd change it and flush the new fuel through the carb bowls too.



Well sure. IF the the bowls become over-full because the needle valves have failed. :roll:



Forgive me, please, if I get just a little sarchastic.........
Just THINK about what you just said.
It's not getting enough fuel. Plugs have nothing to do with that.
Starter fluid does not magically clean a fouled plug just for a few seconds, after which it fouls again.:fight2:

At this point, I'm afraid you're going to have to put some full-strength real carb cleaner directly into the carb bowls (like Gumout or Berrymans B12) or you're going to have to remove them for a really good cleaning.
 
Just wishful thinking about the plugs I suppose. I already have removed the carbs, and using full strength carb cleaner - cleaned the bowls until they shine, removed and cleaned the pilot jets, float needles, etc., and squirted the cleaner through every opening I could find. All this following these instructions:

The GSResources - Carb Rebuild Pg. 1 of 9

except that I couldn't get the needle jets tube out (the only dowel rod I had was a pencil which splintered without moving the jets at all). I'm guessing that's where the problem lies. Tomorrow I go to town for supplies and I'll pick one up. If that doesn't work, well I guess I won't be riding for a while.
 
Wow, what a resource! :bluethum:

Two comments:
Notice that it says to REPLACE O rings, etc. Do you have those? Like from carb kits that you have or are going to get? This could be VERY important.

How are you going to know what the proper float setting is? Got a shop manual?

The lack of detailed re-assembly instructions would make me a little nervous but then I've done basic carb rebuilds in the past with NO instructions! :roll:

Hope you get it all back together and it works!
Regardless of the outcome it will be good experience! :mrgreen:
 
No, I didn't replace the O rings. They seemed pretty good, but since I'm going to do it all again I will. I have access to a shop manual, and I'll get my very own in a couple of weeks. I got the dowel rod "tool" today along with a bunch of screws that needed to be replaced (not on the carbs).

I also got a plug wrench (18 mm by the way). The plugs are rather black like they've been run too rich. Perhaps after I do a more thorough carb rebuild that will clear up, but if not I'll fix it some more. I did get a new set of plugs but I'm going to hold off on replacing these until I get the carbs finished.

Yes, this is great experience. I do hope, though, that runs when I'm done. I'm not a mechanic but I think I'm clever enough to reassemble them properly. Though it's been several years, I have rebuilt the carb on my car and then my wife's. On her car, that is. ;^) So I have a little basic prep, carbs 101 so to speak, under by belt.

Thanks again for all your help. I'll let you know the results.

~Ken
 
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