carb boots = rough idle?

[motman]

For some reason my 85' GS700e runs great when the engines cold but once it warms up it wants to die.

When I say it wants to die, I mean it won't idle.

I can keep it at an idle with the throttle, but if I don't give it gas it will die.
Once I can tell the RPM's are going below the normal 1100-1200 I give it a tiny bit of gas, then it will go up to about 2k RPM then it floats for a couple seconds around 2k RPM. Then goes back down to idle and then slowly sputters and dies.
I want to say that it's my carb boots, but why if that were the case why would it run fine when the engines cold?
The carbs were just cleaned last fall and it was running well then.

Also, I was told I need to replace the clutch push rod seal.. Is that something hard to do??

Thanks GS Resources and happy easter!

 

[motman]

Oh yeah and when I was riding yesterday she died and I couldn't get her started. Then I eventually got home and cleaned the air filter and she started up like there was nothing wrong. Now we're back to the same place..

 

[tkent02]

The clutch pushrod seal is easy. Troubleshooting an idle problem on an unknown bike from afar isn't.

What routine maintenance has been done?
Valve adjustments?
Carburetor cleaning? Synchronizing? Modifications?

Yeah, probably something is leaking somewhere.
Air or fuel leaking someplace it shouldn't.
Something always leaks.

 

[jbs80106]

sounds familiar...

sounds familiar...

My 650G doesn't like to idle on her own. If I close off the choke once warm, when I stop I too have to pump the throttle. If I run w/choke a bit open then she's okay, but that is NOT optimal for a normally running bike!

I suspect I've needed new carb boots for a few years, just not the funds to fix her proper. I would assume when your bike is cold you're starting with full choke on. That means running rich. Okay for warm-up, but not for longer durations.

Some say once she is warm, and on center stand, spraying on some WD-40 or lube around the carbs will give you some indication. If she labors when warm w/choke closed, and a spray of lube in the carb area makes her rev up, then you're leaking air around the boots and running lean. (My problem). I think boots are about $20 each, so figure $100 per side to fix(?).

I live at altitude (~7000 ft) so I've the added complication of knowing if the carbs were ever adjusted for altitude.

Its not 'normal'. Sign something isn't adjusted right....

 

[motman]

well the only real maintenance records I have say the valves were adjusted in 2003 at 4,911 miles(it's still currently only at 6k miles).

Then a whole page of more maintenance, gaskets, etc..

Then in 2007 the carbs were adjusted, replaced oil filter, plugs, etc..
It says it recommends these things though.. chain, sprockets, clutch pushrod seal, and fork seal.

I just bought the bike 7 months ago though, and I know it went to the shop to get the carbs cleaned and adjusted, oil changed, before I got it. I do know the fork seal still needs changed though, that's why I'm assuming the 2007 records are the most up to date.
I can see two of the carb holders cracking though.

I ordered 4 new carb boots and will get those replaced next week, then next will be the clutch pushrod seal and fork seal. Is there any easy way to add more oil to the front suspension?

 

[motman]

Yeah so I'm waiting for the carb boots in the mail and I was just looking at the air box side carb holders and I see that some of them got kind of torqued out of the airbox so they aren't seated with the air box. They seam to be in good condition though(unlike the engine side carb holders).
So I'm still going to replace the carb boots and then I'm sure it will be running like a dream again.

 

[BassCliff]

Greetings and Salutations!!

Greetings and Salutations!!

Hi Mr. motman,

I must apologize to you. Here you are with 18 posts and I have yet to give you your "mega-welcome". In it you will find good, solid information on how to restore and maintain your motorcycle. Most of us do our own work. You'll find lots of "how to" guides with pictures on my website for most routine maintenance tasks. Granted, my bike is an 850, but the principles will be the same. For starters, see my guide on Air Intake Repair (a PDF file). Welcome to the forum.

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", the Carb Rebuild Series, and the Stator Papers. 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

 

[jbs80106]

Did you oil it?

Did you oil it?

Oh yeah and when I was riding yesterday she died and I couldn't get her started. Then I eventually got home and cleaned the air filter and she started up like there was nothing wrong. Now we're back to the same place..

Stock foam air filter needs to be re-oiled after you clean it. Actually, mine was bone dry the first time I looked at it. Bought oil/cleaner kit from the stealer for like $12 or something.....

 

[motman]

Alright so I got the parts and I'm ripping her apart. How do I get the air box out in my GS700e??

The airbox is like stuck in the frame. Do I have to take the carbs out before I can get the airbox out?

Thanks

 

[tejasmud]

Do I have to take the carbs out before I can get the airbox out?

Thanks

Yes, Sir.

Even then, some say it will not come out without hacking it out, removing the engine, ect..

I don't remember, but I do know it will not come out easily even after the carbs are out..

Maybe remove the intake flanges on the head and it might pull out.

 

[motman]

Yes, Sir.

Even then, some say it will not come out without hacking it out, removing the engine, ect..

I don't remember, but I do know it will not come out easily even after the carbs are out..

Maybe remove the intake flanges on the head and it might pull out.

Oh, ok thank you sir! I was wondering why the bottom of it was so dirty..

Well as long as I can get the carbs out without getting the airbox out I'm happy.

I just read in BassCliff's link that the airbox comes out first.

Thanks man, I'll keep you guys updated!

 

[tejasmud]

Oh, ok thank you sir! I was wondering why the bottom of it was so dirty..

Well as long as I can get the carbs out without getting the airbox out I'm happy.

I just read in BassCliff's link that the airbox comes out first.

Thanks man, I'll keep you guys updated!

If you remove the 2 bolts under the seat by the gas tank to the air box, and the one under the right side (possibly left) on the bottom of the box it will make removing the carbs easier though.

With old airbox boots and intake flanges it can be a struggle, and yes new ones make it much easier to work the carbs in or out, ect.......

But, pushing down and pulling up while pushing or tilting them forwards and backwards on the carbs to wiggle them out helps.

Also, once the carbs are down and out one side a slightly it is easier to undo the throttle and choke cable than trying to get to it with the carbs still in the boots.

All the while try not to bend up the clamps too much.

 

[motman]

Ok great, I have a feeling the airbox side holders were replaced at some point or another in the last 10 years. They seam a lot more soft and rubbery, but I'm hoping I'm not mistaken and they crack while trying to get the carbs out. Anyways I just had to go run around town for some o-rings and now I have to go do the dirty.

 

[Guest]

I haven't heard anything about the shape of your fuel tank. These are old bikes. There have been a lot of years for rust and all sorts of stuff to accumulate in that tank. It will eventually find it's way into your carburetors. New intake boots are a good thing. A little dielectric grease on the insides of the boots, make it a lot easier to install the carburetors.

 

[motman]

The gas tank is pretty rusty, I cleaned it out today and dried it.

So I tried to start it and it will turn over but it won't start. It backfired once as I gave it some throttle and I gave up after that.

What is going on? Is the idle too low?

Why would it backfire?

I did notice a fuel leak in the tank petcock, the o-ring needs replaced so I ordered one of those.

Could that be why it backfired and isn't running? Because I could hear the gas tank was pressurized and releasing some air.

 

[BassCliff]

Hi,

Your gas cap should be vented. It sounds like you need to take the cap apart and clean it.

You're working with a 25 year old machine. Go through the maintenance lists in your "mega-welcome". They are guaranteed to deliver you to GS nirvana, if you take no shortcuts. Let us know how it goes.


Thank you for your indulgence,

BassCliff

 

[tejasmud]

So, motman.

Still no starty.

You now have the new carb flanges mounted with new o-rings, carburetors installed, and cleaned out the tank.

Pulling the carbs and reinstalling them should be a "piece of cake" now.

You mentioned that you purchased the bike some months ago, and the carburetors were cleaned and adjusted just before you purchased the bike.

I would recomend pulling the carbs back off and cleaning them correctly.

Break them down, dip, new orings, and sync.

But, to be honest, the reason I know how to remove the carbs by memory is because if a bike sits for more than a few months the tiny passages can and usually get clogged by the gum/varnish left behind from the fuel after it evaporates and there will be problems starting and getting the bike to idle.

I have experienced this many times due to my laziness in storing my bike and not treating the fuel. So my practice of removing and installing carbs is pretty good.

Now, if you trust the PO, and you know the carbs are/were cleaned and adjusted, pull them back off.

Here is what I have done in the past, but I knew the carbs were in good shape, and just needed the small holes cleaned out.

This is a "short cut method," which if it doesn't work it is actually the "long cut method" being you really need to do a full disassembly and rebuild.

Remove the float bowls on the carburetors. If they have black/brown gum/residue inside the bowls, again a full rebuild is really needed. But if they appear to be free of major gunk, there should be a rubber cap/plug covering the "pilot jets" in each carb. If you look through the "carb rebuild series" on your "mega-welcome" you will see the steps on making a tool using a piece of wire to poke the tiny passages. (Step #66) I normally use one piece of copper wire from a 18g stranded wire. Poke it through the pilot jet to clean the hole. If the carbs are clean inside you may be able to just poke the pilot jets without removing them. These control fuel to supply the idle circut. Cleaning out the air/fuel screws would be a good idea also. Then look at the steps #75 through #78, these provide fuel to the choke function, and poke these tiny passages. Then use spray carb cleaner to spray through all these holes. With saftey glasses, prefered. Carb cleaner burns like a "some beech" if induced in to an eye. Make sure the cleaner blows through the passages.

Check the slides inside the carburetors by lifting up on each one. They should move freely and close without any sticking. If they don't, again the full cleaning is a must.

Put the carbs back together, and back on the bike then try and start it.

This method usually will get the bike started and running if the carbs have been rebuilt properly in the recent past year or so.

Being I have not seen your carbs, or actually know the current/past history of them tells me to say do a full break down and cleaning. (the "non short cut method").

I would also check the oil to see if it smells like gasoline. If it does, the petcock/fuel valve at the tank needs to be replaced. Or, try your skill at rebuild.

You can test it to see if it is functioning correctly also, but not knowing how old it is, it is bound to go out in the near future. I would just replace it.

I don't know why I even wrote how to "short-cut" carb cleaning....

If it were me, I would just break them down and dip, replace the o-rings, sync, and have the knowledge they are done correctly and any other potential problem resides elswhere.

E