Need help on 1979/1980 gs550

[wolfronin]

When the bike was purchased it was "ride-able." Previous owner said it was a 1979 GS550 with an 1980 GS550 Engine. I don't know enough about these bikes to verify this. Bike sat for over a year before I got to it. I'm in the Navy and between a deployment and shipyard time, plus a bit of moving around (moved 3 times in under a year) I just had a hard time getting to the bike. Went to start it and it wouldn't start.

Replaced the battery and spark plugs and it would start but idled really rough but I could ride it after a lengthy warm up time, about 10-15 mins. Wouldn't even take any throttle till after 10 mins and I couldn't turn the choke completely off till about 12-15 mins. When I pulled the old plugs they were jet black and wet, probably from trying to start the bike and it not starting.

Figured cleaning the carb would help the bike. I took the cheap route and used a fuel system cleaner, pouring the bottle into the gas tank. The fuel system cleaning specifically said for carbs. After a little while I noticed a dramatic improvement in idle. Not too much later, I can't ride the bike. Bike idle is low, idle screw adjustment has no effect. Bike runs really rich and will only run on full choke. Very difficult to get the bike to take any throttle. Likes to die with the smallest input on the throttle. Idle also "surges", however Idle is still smoother than it used to be. Idle sits around 1000-1500 and will surge to 2000-2500. Idle speed doesn't change as the bike warms up.

My next step will probably be to take the carbs off, clean them, replace software and tune/balance the carbs. My first thought is the carbs aren't setup correctly. My second thought is maybe a vacuum leak? I plan on replacing hoses along with taking the carbs off and cleaning them. Haven't pulled the plugs out since I installed them. I won't have a chance to do that till Wednesday.

Anyone have any other thoughts/suggestions that I probably overlooked?

As far as my experience goes, I am a Navy Mechanic.. however; my area of expertise is with diesel engines. I have a very basic understanding of how carbs/choke/intake/exhaust all work together.

[nejeff]

Someone will be along shortly with all the info but in the meantime who could you add your location to your information and post what bike you have in the signature. Very likely someone in close proximity to you could offer a hand.

[alke46]

You are wasting your time until you visit basscliff's web site. These old machines have a standard procedure that needs to be followed to get out all the old "gremlins".

[tom203]

What carbs do you have on this replaced engine- CV or VM ? smooth top like in attached pic?
These carbs require a thorough cleaning to make them happy. Head to this link for info overload

http://members.dslextreme.com/users/bikecliff/

[MisterCinders]

What carbs do you have on this replaced engine- CV or VM ? smooth top like in attached pic?
These carbs require a thorough cleaning to make them happy. Head to this link for info overload

http://members.dslextreme.com/users/bikecliff/

Tom's post is a trick question. All carbs require a thorough cleaning to be happy, VM and CV.

[mike10]

carb cleaner

I think the pour in carb cleaner may be just for maintenence once in a while after the carbs have been cleaned well. If not I think it just breaks more gunk loose and makes things worse. Very good and easy to follow carb cleaning instructions on this site. Or if you have the money and not the time there are guys on the site who will clean them for a good price. I would not trust anyone else but guys here, to clean them if you don't do it yourself. Also just so you know, if you have CV carbs, the bike will not run or will be imposible to tune. Without stock aircleaner on and air tight.

[wolfronin]

Took a picture to give you guys an idea of what I'm working with today.

BTW. Started it up today,and it would take throttle, although the engine response was sloppy. Inputs on the throttle were met with delayed reaction.

I was also getting exhaust backfire on the left side (left side when sitting in seat facing foward), The backfire is a new symptom. Engine still seems to run rich. The more I mess with the bike, the more everything really points to dirty carbs... where is a good place to pick up rebuild kits for these bikes?

The plate on the Engine says "GS550 - 192134"

[tom203]

VM carbs. head to this link and fiddle with it to size it so you can read it!

http://members.dslextreme.com/users/bikecliff/images/vm_carb_rebuild.pdf

[BassCliff]

Greetings and Salutations!!

Hi Mr. wolfronin,

First of all, I appreciate your service. It's not easy in times like these.

What you have there is a 30+ year old motorcycle that needs at least 20 years worth of maintenance. In your "mega-welcome" you will find a couple of maintenance lists. Every item on these lists must be properly addressed in order to have a safe and reliable machine. Taking shortcuts or skipping steps can leave you injured or severely dead, or at least very frustrated. Let's get started.

Pick up an O-ring kit from http://cycleorings.com and the necessary gaskets. Do not waste money on aftermarket "carb kits" that are incomplete and contain inferior parts. Just disassemble the carbs completely, soak all the metal bits in carb dip for up to 24 hours, blow out all the internal passages with carb spray and compressed air, then reassemble. Use the carb rebuild guides on my website as reference. Even though you don't have the BS series carbs, it would be good to go through the CV carb rebuild tutorials anyway, to get an idea of proper procedures. There is also a VM carb rebuild guide on my site. (Many thanks to the authors of those guides!) Your bike has VM carbs.

Now let me dump a TON of information on you and share some GS lovin'.

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

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!"....

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...



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!

Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[wolfronin]

After reading through all this information... I think I'd like to just go ahead and do the "right" think and just do a good tear down and rebuild.

I appreciate all the the info and all the pokes and prods to do the job "right." Sometimes we just want to get out on the road and have fun and we neglect the machine to achieve that...

Anyway, trying to get a parts/materials list together and I was looking into parts to get the Air intake system up to par, and notice cycleorings.com doesn't carry the size orings I need for my '79 GS 550. According to his info I need a 28mm Orings for starters...

How are these Orings measured? Inside Diameter? Outside Diameter? Nominal?
What thinkness?

As far as getting my hands on boots and the like? any suggestions? Other models that have parts that fit that I might have better luck finding? I do know a few tricks to try and revitalize old hard rubber if I need to go that route.

[tom203]

O-rings are measured by cross section and inside diameter- so a 2.5 mm by 28 mm o-ring would be 2.5 mm thick with a 28 mm inside diameter.
If the machined o-ring groove was 2.00 mm deep, you'd likely want a 2.5 mm thick o-ring so as to compress when tightenned.
Against the cylinder head is hot, so Viton is really the only suitable material- your local store is unlikely to carry Viton o-rings.
Visit this link for more info

http://www.theoringstore.com/

[wolfronin]

The O-rings I'm not too worried about. I can get those easy enough.

Sadly, we classify o-rings much differently in the Navy. I guess I shouldn't be surprised by that

Its the all the rubber pieces that really concern me. I haven't really found any for the 550cc yet.

[7981GS]

Why not just order the O-ring kit?

https://www.cycleorings.com

Eric

[wolfronin]

They don't carry the o-rings or pieces for the air intake for my bike. They only carry them for the larger bikes... and its the boots/rubber couplings that are the biggest concern.

Here is the quote from cycleorings.com:
"77-79 550's use 28mm O-rings (which I don't carry) and 16mm screws."

I don't think I have any leaks on the air intake side. From the Air box to the Carbs and from the carbs to the engine. The old rubber is a concern though. When I take it apart and try to reuse old rubber, the odds of a leak go up. I either need new air box/air intake pieces, or I'm going to have to try a few tricks to "revitalize" the old rubber.

I know there are some products the RC car guys use for RC car tires. I also know that a silicone product can help me seal leaks from cracked rubber, etc. I would still prefer new pieces though. I don't know if I can make the larger CC engine parts work.

As a last resort, I also have access to an almost limitless supply of Krytox.

[tom203]

They don't carry the o-rings or pieces for the air intake for my bike. They only carry them for the larger bikes... and its the boots/rubber couplings that are the biggest concern

As a last resort, I also have access to an almost limitless supply of Krytox.

Yeah, just disturbing 30 year old rubber stuff like this is likely to cause failure. I spray my carb boots with silicone as I wait for Ron Popeil to make a miracle carb boot restorer.
Anyway, what is Krytox- a submarine's savior?