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Puzzling Carb Issues

  • Thread starter Thread starter Samiam
  • Start date Start date
S

Samiam

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Hi All! First off this is my first post on the forum. I have been a GS owner for about 6 months, but I have been wrenching on bikes for a couple years now. This post is out of desperation.

I rescued my beautiful 1980 GS550E off the side walk where it had been sitting for several months. It has 13,500, and is completely stock except for the Vetter Quicksilver fairing, dealer installed when new. The bike didn't run when I got it, in fact I had to push it over a mile to get to my garage. After dissembling and cleaning the carbs, the bike refused to run for any length of time. Replacing a broken petcock, NOS air filter, and putting in a Dyna S ignition (and timing it) got me some good spark. Finally it coughed into life. However, it consistently ran lean- very lean. It got so bad that the bike wouldn't idle any more and, out of fear of doing permanent damage, I took it off the road. I put on new manifold boots and O-rings, and 4 new K&L rebuild kits, and then carefully set the float heights to spec 22.4 mm. The main jets are 92.5. I put the carbs on and nothing. The bike cranks, the plugs spark and nothing. Fuel flows into the bowls, but not much. I tickled the floats by blowing in to the breather tubes and got the bike to cough. Why, if the floats are at spec am I not getting enough fuel in the bowls? Any thoughts will be appreciated!
 
It could be that, with the needles from the rebuild kits, the factory spec float heights are no longer valid.

I would suggest that you buy the fuel level measuring tool that consists of a clear plastic tube that is attached to a fitting that screws into the float bowl drain. I bought mine form Z1. Then you can observe and set the actual fuel level to factory spec.

http://www.z1enterprises.com/Fuel-Level-Gauge-Tool-Kawasaki-Suzuki-4160.aspx

Of course you have to do a very thorough cleaning of the carbs and install new O-rings as described on BassCliff's site.

Brian
 
Thanks for the welcome and the advice! I will go ahead and check the fuel level and air box. Mine has a little ledge under the filter that looks like it was added by a previous owner. The petcock is NOS, but without the prime setting. I was going to try replacing the vacuum line. One thing I noticed when putting the floats back in their slots was that they didn't all seat the same. Holding them up to the light it looked like the needle valves and seats were level, yet some of the floats hit bottom before the others. The tongues were all at the same height. Only thing I could figure was that the individual arms the floats were glued to were bent out of shape. Has anyone else encountered this?
 
Samiam said:
Why, if the floats are at spec am I not getting enough fuel in the bowls? Any thoughts will be appreciated!
Click to expand...
Just a couple of thoughts here.

Do you know for sure that you have no fuel in the bowls?
After placing the petcock in the PRIme position for about 30 seconds, put it back to RUN, then pull one (or more) of the drain screws from the float bowl(s) and measure the amount to compare with the other carbs.

Also remember that just because there is fuel in the bowls does NOT mean it can get to the jets, where it needs to be. You mentioned installing rebuild kits (not generally recommended here), but never said anything about cleaning the carbs. Not just a spritzing of some spray here and there, either, you need to SOAK those carbs for a full 24 hours, after fully dismantling EVERYTHING (except the throttle plates) from the carb body. There are plenty of references to carb cleaning on the board, you can find the best one at BassCliff's site (he will be along shortly with your "official" welcome package). Scroll down to see his bike, then look in the top of the right column, you will see a next to the carb rebuild guide.

.
 
His "NOS" petcock doesn't have a prime setting apparently. (which leads me to think it isn't NOS Suzuki, as even the hated 1980 petcock has a prime setting)
When you "cleaned" the carbs did you assure that you cleaned out all the tiny passages with a strand of copper wire? And it's always a good idea to blast some carb spray through them and watch that the pattern is uniform. Have you checked the plugs to see if they're wet with gas?
 
Get rid of the petcock, connect a small funnel to the fuel line and fill the funnel with fuel. The fuel will run down the funnel into the bowls of the carbs...you'll know when to stop, trust me!
You may need some help, get someone to hold the funnel/bottle whatever it is you want to use and then try and start the bike.

What you want to do is eliminate things one at a time.If you think ur fuel is not getting to the carbs, replace it temporarily with something else...etc.

Start by your fuel supply...Process of elimination.
 
Great feedback here! The petcock came in a Suzuki box. Chinese knock off perhaps? I cranked the engine for about 45 seconds, in short intervals so as not to over heat the starter, and then pulled the drain plugs from the the outer bowls. There was fuel but not much (when I removed the carbs again the bowl was about 1/4 full. When trying to start it I tried full choke (fully functional) no throttle, no chock some throttle, still nothing. I pulled the plugs to check spark and they were bone dry. They only way I was able to get some life out of the engine was by tickling the floats (blowing through the breather tubes). This got me a cough and a sputter, but as soon as the overflow disappeared so did any sign of life.
Ok cleaning. On three occasions I have completely dissembled the carbs. All jets, plugs, o-rings, everything. even drilled out the little aluminum idle scew cap and removed the screw and it companions. The bodies spent 4 hours in a sonic cleaning tank with boiling water, and were then rinsed and blown out with compressed air. Every jet and o-ring was then replaced with new(I checked each new one against the original to make sure they were the same size jets.) I have done this twice. gssuzukixxx's recommendation of a fuel level gauge sounds good though. One thing that has worked in the past(in place of the 'Prime' setting)is to remove the vacuum line from the engine and suck very gently until I hear the petcock spring disengage. I will have to check the level with the floats on spec. Thanks again everyone!
 
Yeah, sounds like a fuel issue....go the funnel trick. Should work a treat!
 
Cleaning the carbs in an ultrasonic cleaner is a good way to go, but I have a feeling they need something a bit stronger than boiling water to dissolve those fuel clots. :-k

.
 
Your carbs are messed up.

Did you take them all the way apart and soak each carb body? Did you see the carb rebuild tutorial linked in my signature? Did you replace all the O-rings with a kit from cycleorings.com?

Short cuts are long cuts when it comes to bike maintenance.
 
Ok, so first off, Ed, LOVE the new avatar. :D

Second, you're using those jets that came with those silly junky rebuild kits???

Tsk Tsk.
Typically the only thing that actually NEEDS replaced in these are the orings. The jets simply need soaked with the rest of the bodies and bowls in the juice.
While I've never used an ultrasonic cleaner, I have a hard time believing that simple H2O would break down the crap I've seen in some carbs.
But I'm not trying to bust ya nuts. :)

Those jets in those kits however are of questionable quality. Sizes have been found to be incorrect comparing side by side with actual mikuni equipment, and the brass has been reported to be subpar quality...if that really matters.
But, were I you, I'd put my stockers back in just so everything is known to be correct.

Apart from that, if you KNoW your carbs are clean, your jets are clean and correct, what are you pilot mix screws set to? ( the ones you called idle screws that you had to drill the cap off of to get to...not idle screws By the way, just for future reference. :) ) generally they need to be 2.5-3 turns from light seated as a starting point.
 
I am on Eds side here..I would get the new orings from Robertbarr here on the forum and tear them down COMPLETELY and give everything a 24 HR soak in some new or relatively new Berrymans. Followed with the fine wire thru every hole in the jets, pilots, and emulsion tubes, lots of carbs spray in all orfices and lots of compressed air. When ya think youve sparyed enough...spray it all again to be darn well sure. reset the floats and use a slave tank to get the bike fired up. Once its running and will stay running on the slave tank, then put the tank back on and see if the symptoms returns. That way youll find out in a few minutes if the petcock isnt delivering enough fuel. Heres my 10 dollar slave tank. Its an auxillary washer tank with a old generator gas shut off on it. Great for doing carbs syncs or whatever with the tank off.


 
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Greetings and Salutations!!

Greetings and Salutations!!

Hi Mr. Samiam,

Pay particular attention to the maintenance lists in your "mega-welcome" below. There are "how to" guides for most of the procedures on my little website. I know that the links below are very near "information overload" but they will go a long way to help you get your bike sorted. Take no shortcuts so you and your bike will be insanely happy.

Let me dump a TON of information on you and share some GS lovin'. :D

I just stopped by to welcome you to the forum in my own, special way.
big_hi.gif


If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....
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Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", "Top 15 Tips For GS Happiness", the Carb Cleanup Series, and the Stator Papers. All of these tasks must be addressed in order to have a safe, reliable machine. This is what NOT to do: Top 10 Newbie Mistakes. Now let me roll out the welcome mat for you...

carpet.jpg


Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike! :D

Thanks for joining us. Keep us informed. I will put you on my prayer list.

Thank you for your indulgence,

BassCliff
 
Thanks again guys I really appreciate it! I found out why you dont like rebuild kits. While disassembling the carbs to dip, per your advice, I removed the mixture screws to find that two of them had the needle tips twisted of in their tiny holes. #%$^@!!!!!! :o :banghead Now I sitting here trying to push them out with a piece of wire.
 
The Mikuni screws will break off too, you just can't bottom them out or they will get stuck and break.
 
im doing something similar with a pin and some wire. as soon as I get the stupid things out, if I ever do, then Im putting the stock ones back on. Lucky I kept all the old stuff.
 
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