850 carb rebuild

[drmaxdc]

I just got a 83 GS850GL that was a one owner with 900 miles on it but has not ran for a long time. I rebuilt the carbs the way this site says with all new o rings. I tried to start it last night using an auxillary fuel tank when gas started pouring on to the floor. It was late so I didn't get down to try to see where it was coming from, probably couldn't with the air boxes on anyway. Tonight I will take the air boxes off and turn the gas on to try to see where its coming from. I did use the new needle valves out of the kit. I set the floats at .88. Any thoughts? Thanks.

[Nessism]

Your float needles are stuck which is causing the carbs to overflow and fill up the airbox. Sometimes this problem is as easy as the float hanging up up because you had the carbs up side down on your workbench during the cleaning process. You might want to take a plastic screwdriver handle and rap on the floatbowls to make sure the float drops down where it belongs. If the carbs still overflow you need to pull them back off and look inside to figure out what’s going on with the float and needles.

As a side note, aftermarket carb kits are typically of lesser quality than the OE Mikuni parts. If you read the archives here you will find lots of advise against using “carb kits”. General forum wisdom is to order an O-ring kit from cycleorings.com and reuse as much of the OE brass as possible. Also make sure you fully break down the carbs and soak them in carb dip, don’t just flip them over to remove the float bowl and dump a bunch of crappy jet parts inside and expect the bike to run properly.

Good luck with your restoration.

[Larry D]

Did you get the bowls and drain bolts back in securely ?

Sometimes in the rush of excitement to get the bike running, the little things are missed........don't ask me how I know.

[drmaxdc]

I did the complete dip and cleaning like it shows here. I will take the carbs back off tonight and put the orginal needle valves back in with the new orings I got in the oring kit and try that if the tapping doen't work. Could using the auxillay gas tank cause the flooding? Can I leave the airbox off just to see if it runs?

[Dave8338]

I did the complete dip and cleaning like it shows here. I will take the carbs back off tonight and put the orginal needle valves back in with the new orings I got in the oring kit and try that if the tapping doen't work.

Could using the auxillay gas tank cause the flooding?

Can I leave the airbox off just to see if it runs?

1. Yes, to some extend. That being said, if the float valves are doing ther job, you can use anything that holds fuel (within reason) to test run your bike. The petcock is designed to shut OFF when the bike is not running. Without this feature, there is additional pressure on the float valves and if not seating correctly, will compuond the problem.

2. You can, just to see if the bike fires. Keep in mind, it WILL NOT run correctly (WAY TO LEAN) and you will not be able to make any kind of final settings, to ensure that the carbs are set correctly. I suggest putting the air box back in and leaving the cover off, with the filter installed, as a better method. Even this option will do nothing more than confirm that you can get the bike to run. Your throttle response will be sluggish and your base idle will be higher (1500-2000) than is should be.

[chef1366]

Did you put the new o-rings on the fuel rails connecting the carbs?
I've seen new needles that have no spring action, turning the carb upside down compresses the needle and the float settings aren't even close. (did you have to bend the float tab alot?)
Are you sure you didn't split an o-ring on an inlet valve (float seat)
Spit is your friend (lubricant) while installing new o-rings.

[drmaxdc]

I did put all new orings on everthing and used a dab of silicone on the orings on the needle valve. I did have to adjust the tabs because of the new needle valves. I turned them upside down a few times and everything seemed to work ok.

[Nessism]

I did put all new orings on everthing and used a dab of silicone on the orings on the needle valve. I did have to adjust the tabs because of the new needle valves. I turned them upside down a few times and everything seemed to work ok.

Red flag here. No need for silicone on the needle seat O-rings. Maybe the needle is stuck now from the sealer.

[rideOn]

if the floats get bent out a little during height adjustment, they can catch on the bowl and not close the needle valve. don't ask how i know.

[mrb302]

if the floats get bent out a little during height adjustment, they can catch on the bowl and not close the needle valve. don't ask how i know.

Also, if you have the carbs upside down while replacing the float needle and you think upside down means you need to turn the needle upside down (and you are stupid like me) then what you actually just did is installed the needles upside down and gas will never stop flowing from the carbs/airbox until the gas tank is empty. Don't ask me how I know that one either.

[drmaxdc]

If I have to take them apart again tonight, can I use the new needles with the old seats or should I use the old needles also ( if I can find them), they all looked ok when I changed them.

[Dave8338]

If the old needles show no signs of pitting where they hit the seats, I'd use them. They have a cleaner taper than any aftermerket needle that I've seen.

[Suzuki_Don]

Red flag here. No need for silicone on the needle seat O-rings. Maybe the needle is stuck now from the sealer.

ED maybe he means silicone grease, not silicone sealant. I agree, it would be disatrous to use sealant in there.

[Steve]

Could using the auxillay gas tank cause the flooding? Can I leave the airbox off just to see if it runs?

Yes, the aux. tank can cause the flooding, but you would have to be doing a couple of things wrong.

How high is the aux. tank over the carbs? If it's much higher than the stock gas tank, it's adding head height, therefore, pressure, that the float needles just can't hold back.

If the tank is at the proper height, the float needles would have to be on the marginal side for the needles to leak.


Yes, you can leave the airbox off "just to see if it runs", but don't expect any throttle response or operation above idle speed.

Unless you provide a bit of restriction on the intake. That can be provided by simply folding a shop rag in half and draping it over the carb intakes. Use a zip-tie to hold the rag to the outer carbs, keeping it taut over the inner ones. This is actually good enough to go for a short ride, but not good enough to do any jetting checks.

.

[drmaxdc]

Yes, I meant just silicone spay lube that I dabbed on the oring with my finger. Anyway, I went out last night and took the airbox off and turned the gas on and number 2 carb., the one that the gas line hooks to, started pouring gas out of its mouth. I took the carbs off and did not see any problem but I put the original needle valve and seat back in (cleaned), reset the float and put it back on and it did the same thing. I did have my auxillary tank a little higher then the stock tank would have been, I will lower that and try to shorten the gas line to it, but the other 3 carbs seem to be ok. I tried starting it but it didn't even try to fire like it did before, then the starter stopped working and only clicked. Good battery, on charger, must be the solenoid. I tried to short accross it but too many sparks and too much gas on floor. I will try that tonight. There is no way if the generator bolts are in the wrong order that they could hit something to keep it from spinning over is there? I will figure this out if it takes me all winter, with some help of course.