Where do I start?

[gallion_t]

Hello all. This is my first time posting as I just bought my first bike, an 81 gs850. When I got it about a month ago it ran great. However after the first tank I fill up with regular not knowing any better. Shortly after the bike started dying on me at idle followed by an afterfire on the left side of the engine. I switched over and started running premium with a fuel additive to hopefully clear up the issue but that didn't help. I have since changed the sparks plugs and that didnt help either. I know have a very irregular idle. During a 10 mile ride my idle will go from 2500rpm down to dying at idle, then back up to 2500. Finally my fuel milage has dropped drastically too. this last tank maybe got 80 miles.

So far what has been done to the bikes is:

oil change
primarly gear oil change
secondary gear oil change
speedo cable change
new tires
new rear brakes and rotor
New spark plugs

Does anyone have any ideas of where I should start to look to fix my problems? Do I just need to rebuild the carbs and sync them or is there somewhere else I should look? I should note the bad gas milage started after I got the bike back from the shop getting new tires. They said they did a quick tune job on the carbs.

Thank you everyone for the help. Im hoping the issues can be solved easily.

[posplayr]

Hello all. This is my first time posting as I just bought my first bike, an 81 gs850. When I got it about a month ago it ran great. However after the first tank I fill up with regular not knowing any better. Shortly after the bike started dying on me at idle followed by an afterfire on the left side of the engine. I switched over and started running premium with a fuel additive to hopefully clear up the issue but that didn't help. I have since changed the sparks plugs and that didnt help either. I know have a very irregular idle. During a 10 mile ride my idle will go from 2500rpm down to dying at idle, then back up to 2500. Finally my fuel milage has dropped drastically too. this last tank maybe got 80 miles.

So far what has been done to the bikes is:

oil change
primarly gear oil change
secondary gear oil change
speedo cable change
new tires
new rear brakes and rotor
New spark plugs

Does anyone have any ideas of where I should start to look to fix my problems? Do I just need to rebuild the carbs and sync them or is there somewhere else I should look? I should note the bad gas milage started after I got the bike back from the shop getting new tires. They said they did a quick tune job on the carbs.

Thank you everyone for the help. Im hoping the issues can be solved easily.

Well the hand writing is on the wall; you do need to pull the carbs and see what misfortune you encountered at that Shop?

[gallion_t]

Why would that account for the erratic idle and afterfire that developed before the bike went to the shop?

[Steve]

First of all,


Second, go back to that shop, DEMAND to know what they did to mess up your carbs.

Third, drain the "premium" gas out and put REGULAR gas in the tank. That is what is supposed to be there.

Fourth, get ready to do a BUNCH of maintenance. Unless you know the previous owner and really trust him to tell you the truth, you can assume that NOTHING has been done and you will need to do it yourself. Start with a carb cleaning and valve adjustment. You have already done some of the other stuff that is necessary.

Fifth, while you are waiting for parts for your carbs and valves, do a thorough inspection of the brakes. Too many times the brake fluid is as dark as root beer and the pistons are corroded in their bores. It's not hard to rebuild the calipers and master cylinders, just takes a little time and a few bucks. You should also look into replacing the brake hoses. Suzuki recommended replacing them every two years, I'll bet that yours are original.

BassCliff will be along shortly with the official Welcome Package with all the links and required reading, but in the meantime, do NOT buy carb rebuild kits. All you will probably need will be a can of Berryman's (or GUNK) carb cleaner dip, a set of carb and intake boot o-rings from cycleorings.com and a few days of time. The only other possible need would be float bowl gaskets, they are much cheaper than buying "rebuild kits".

.

[posplayr]

Why would that account for the erratic idle and afterfire that developed before the bike went to the shop?

plugged idle circuit

[chuck hahn]

These guys are right. FULL teardown and redo the carbs yourself the right way and do all the maintenance or sell it..Half measures will avail you nohting but constant trouble and too many wasted hrs of riding from constantly having to fix something.

You may humble yourself and ask for any local experienced guiys to come by and have a garage day with you..Beers and brats are a helll of a lot cheaper than the alternatives.

[gallion_t]

Thanks everyone. Seems like my carbs are the issue. I've never done a carb rebuild or cleaning before but I'm all for learning. Thats part of the reason why I bought a 32 year old bike.

I have already found basscliffs website and found it very helpful. Thats how I learned how to change all of the fluids and stuff.

[posplayr]

Thanks everyone. Seems like my carbs are the issue. I've never done a carb rebuild or cleaning before but I'm all for learning. Thats part of the reason why I bought a 32 year old bike.

I have already found basscliffs website and found it very helpful. Thats how I learned how to change all of the fluids and stuff.

One thing that could have happened is if you did not have a fuel filter between the tank and carb, and some crude came loose in the tank it would have plugged you carb idle ports causing the condition you describe. If the tank is grungy I would clean it and personally I run a fuel filter as well.

[BassCliff]

Greetings and Salutations!!

Hi Mr. gallion_t,

You've made a good start catching up on the maintenance but you still have a ways to go. It's always best to learn to work on these old bikes yourself because no one else will give a rip about them. See the maintenance lists in your "mega-welcome" and the "how to" guides on my little website. You must PROPERLY perform all the maintenance tasks in order to have a safe and reliable motorcycle. Skipping steps or taking shortcuts will be frustrating at best and dangerous or fatal at worst. You have been warned.

If you are here you probably have a 30 year old motorcycle that needs about 20 years worth of maintenance. In the links below you'll find maintenance lists, documentation, wiring diagrams, "how to" guides, vendor links, tips, tricks, and a whole lot of GS goodness. This is your "mega-welcome". Let's get started.

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!

More links to helpful threads in the forum:
Help! Your Bike Won't Start
DON'T DO THESE THINGS
Help! Your Bike Won't Run Well
Oh God! Pods!


Thanks for joining us. Keep us informed.

Thank you for your indulgence,

BassCliff

[MOC]

Thanks everyone. Seems like my carbs are the issue. I've never done a carb rebuild or cleaning before but I'm all for learning. Thats part of the reason why I bought a 32 year old bike.

I have already found basscliffs website and found it very helpful. Thats how I learned how to change all of the fluids and stuff.

Having recently joined this community and taken the advice of these sage advisors, i would strongly urge you to trust them. Basscliff's website is amazing. Some things you read here may seem at first to be a bit over the top, but they are necessary and worth it. I was intimidated by my carb rebuild at first, but the parts and the labor are very cheap/simple, and the learning process has been gratifying. It's all in how you go about it.

welcome aboard

[gallion_t]

Thanks for all of the suggestion and help so far. I'm looking into ordering everything and am starting to get a little overwhelmed. I dont want to miss something im going to need and have to wait to finish the jobs. Heres what im looking to do.

Carb clean or full rebuild -Which would be recommended? What kits do I need?

Intake O-rings and possibly boots

Valve Adjustment- I will need shims and ?

Im sure there are gaskets and such that would be good to replace while im doing all of this but which ones?

Finally where is the best place to order this stuff from? Ive found carb rebuilt kits, but havent seen the shims, O-rings, or intake boots before.

Thanks again for all the help. I'd really like to get the bike up and running great before the best part of the summer kicks in.

[recycled64]

Sources

For carb 'o'rings and manifold 'o'rings- www.cycleorings.com (member on here, Robert Barr)
For manifolds and OEM!! carb parts-www.boulevardsuzuki.com (opinions vary on that notion as much as there are different suppliers) www.z1enterprises.com is also a much-valued source, also a member here--

[850 Combat]

You don't need rebuild kits. At the most, you need O Rings, gaskets, and float valves. I have used aftermarket float valves from a rebuild kit with success, but OEM are better if you need them.

[Steve]

I will insert my comments into your original questions.

Thanks for all of the suggestion and help so far. I'm looking into ordering everything and am starting to get a little overwhelmed. I dont want to miss something im going to need and have to wait to finish the jobs. Heres what im looking to do.

Carb clean or full rebuild -Which would be recommended? What kits do I need?
Basically the same thing. Cleaning is a part of the rebuild. No "kits" needed, just order o-rings from cycleorings.com.
Along with the o-ring kit, you will need a can of "dip", a few tools that you might already have on-hand and a few that you don't. One that you won't have on-hand is a manometer set to sync the carbs. If you post your location (add it to your profile), one of us might be close enough to give you a hand.

Intake O-rings and possibly boots
Intake boots might be necessary, but they are not cheap: about $28 each. O-rings for the boots are also available at cycleorings.com, along with new stainless bolts to hold the boots on.

Valve Adjustment- I will need shims and ?
Yes, you will need shims, but you won't have any idea which ones until you measure your clearances and check your current shims to see what sizes they are. Procedures are in your service manual (get one from BassCliff if you don't already have one), there are supplementary tutorials on BassCliff's site and I offer an Excel spreadsheet that helps you calculate what shims you need. Look in my sig for info.

Im sure there are gaskets and such that would be good to replace while im doing all of this but which ones?
For your carbs, you might consider bowl gaskets. For your valves, a valve cover gasket and the "half-moons" at the ends of the cams. And anything else that looks like it might need it.

Finally where is the best place to order this stuff from? Ive found carb rebuilt kits, but havent seen the shims, O-rings, or intake boots before.
You will get many opinions on this one. BassCliff's Welcome Page has a list of vendors, along with commentaries on some of them. There are a couple to avoid, due to prices or (lack of) customer service, but each of us tends to have our own favorites. Boulevard Suzuki and G&S Suzuki seem to be among the cheapest for OEM parts. Just keep in mind that virtually NONE of these dealers stock items on their shelves for 30-year-old bikes, so any order you place will take about two weeks to get to you. Z1 Enterprises shows a lot of stuff on their site, and what they show, THEY HAVE IN STOCK. Not all of what they show is OEM, but all good quality stuff.

Don't get carb "rebuild kits". Shims are good at Z1. O-rings at cycleorings.com. Intake boots (and other parts) just about anywhere.

.

[gallion_t]

I just ordered the carb, intake, and dump O-rings along with the stainless steel fasteners form cycleorings.com.

What I have left is valve shims and carb float valves? Anything else I am missing?