Idiot/Non-Mechanic in need of help....

[Chester Gunn]

First of all, my bike is a 1983 GS 650 ? (I think L). I bought it back during the summer, and up until a couple of months ago, it really ran perfectly. Then all of a sudden, the idle went crazy wild...as in 4,000-5,000 rpms..I've been told that this was the o-rings on the intake manifolds. So, I ordered the replacements and started the job of removing the carbs. Once the tank was removed, I noticed that the synch bolt and nut were completely missing from the #2 carb..and that got me to wondering about whether or not this could be causing my idle problem. I polled some of the members, and there were those who suggested that this missing synch bolt could be my problem. Having the o-rings in hand, I decided to go ahead and change them while I had the carbs off..It couldn't be that hard, right??? NOT...I believe that Suzuki welded the manifold bolts to the head on my bike... I never even got the first one of them to budge...I used wd-40, pb blaster, prayer, profanity, and a few other things, and nothing worked. I've been told that some have been able to use vice grips to get these bolts out..I tried that as well. I'd even try an impact wrench if there was enough room for clearance..

So, after being unable to removing the manifolds, I decided to roll the dice and install the new carb synch bolt and put the carbs back on the bike..Well, as all of you know, getting the carbs off is a whole lot easier than getting them back on the bike...but eventually they did go on.. I rigged up an external fuel tank and after several tries, the bike started...I had borrowed a set of guages with the idea of synching the carbs before I put it all back together (I also own a 1984 Goldwing)...Either my fingers are too fat and clumbsy, but I was unable to fit the adapters into the inboard vacuum fittings...after 2 hours of trying to install the adapters, I ditched that idea as well. I decided that if I could just get the bike running, I would take to a local shop and have them synch the carbs..and up until this time, the bike was running pretty good..even with the carbs being out of synch.. and the idle was fine...somewhere around 1100 rpms..So, with all that being said, we removed the external fuel source, hooked the linkage back up, re-installed the fuel tank and anxiously anticipated a test ride.. No sooner than we got it all put back together and fired her up, the rpms shot straight up to 3500....and then to 4,000...Scratching my head, I thought it might have been the linkage, so I pulled the tank, disconnected the linkage and then set the fuel tank back on top of the bike and connected th lines...Fired her up again and she went straight back up to 4,000 rpms..Then, I thought that maybe that I had crossed some hoses on the fuel tank, so I tried that.. The bike fired back up, idled perfectly, and then slowly died...as if it ran out of fuel....obviously the wrong hook-ups for the hoses...So, I turned them back around...and now the bike will not start at all..

This has all taken place over the last 5 days...and if you can't tell, I'm getting just a bit frustrated..but I'm not giving up....Nope, we will get this bike running..I just need some expert help....and if it means tearing it all down and starting over again, then that is what I will do.. What puzzles me greatly is that when the bike was hooked up to the external fuel source (in this case a coke bottle with a fitting drilled into the cap), it ran fine...Idled wonderfully...revved up...the whole nine yards..but when we put the tank back on..the idle jumped right back up...

Any and all suggestions would be greatly appreciated....

Thanks
Chester Gunn/Chula, GA

 

[chiphead]

If you go back in, try a sharp chisel on the manifold screws.
I'm not sure of the petcock design on your model but do you have a "prime" position? This will by pass the vacuum diaphragm that lets fuel flow when the engine starts. Sounds like you are running our of fuel and encountering a lean condition. When you take the tank out of the equation it runs fine. Kinking fuel or vacuum lines when installing the tank?

 

[mike-s]

Things to try.

Things to try.

Firstly welcome to the realms of d.i.y. bike repair, your doomed *manical laughter*

Seriously though there are a few possibilities that come to mind
1) air leak around the carb boots, firstly as you were messing about trying to fit carb balancers to the bike i would check that there isn't a leak from this point on the bodies. Secondly if this is a bust then i would use the quick and dirty way to test for leaks, which is to spray a bit of the cold start assist stuff around the carb boots and to see if the revs increase at all. If you get an increase then there's a strong chance that theres a airleak in the vicinity, you can use a bit more accurately squirted to figure out where. Just be careful as this ether based stuff can knock you out if you have inadequate ventilation.

2) Choke, your still getting this issue even with the choke fully off? also, you didn't mess about with this part of the carbs when replacing o rings? theres a possibility that extra fuel is leaking by and you may now need to check the o rings out in this region of the carbs.

3) float level set correctly? you really shouldnt mess about with this unless your sure you need to tweak the idle/off-idle setting

4) Plunger stickiness is the third factor that comes to mind, the plunger im talking about is the one attached to the diaphragm within the carb. The plunger is directly connected to the needle and if one (or more) of the plungers is sticking and not settling down like it ought, there is a distinct possibility that extra fuel is getting through as the needle isnt restricting the flow sufficiently and causing the same effect as if the choke was actuated. To check this you take the carbs out and flick the plungers up & down gently with your finger to see if any settle further down than they are currently sitting.

I hope this is a good starting point, i've pretty much outlined the things i would look for, in the order i would look at them.

Mike.

 

[mike-s]

If you go back in, try a sharp chisel on the manifold screws.
I'm not sure of the petcock design on your model but do you have a "prime" position? This will by pass the vacuum diaphragm that lets fuel flow when the engine starts. Sounds like you are running our of fuel and encountering a lean condition. When you take the tank out of the equation it runs fine. Kinking fuel or vacuum lines when installing the tank?

Come to think of it, it's a possibility, but not likely. Another possibility is a kink in one of the fuel lines. Either of these would cause a limit in the flow of fuel, but would it cause enough of a restriction to have the engine running leaner but not enough to make it cut out?

I would have thought that the engine isn't likely to be drawing enough fuel for a lean condition to be caused at this rev range, every time i have a hint of fuel draw problem at idle my engine pops and farts and complains but doesn't rise in revs too much (1100 >3.5k+ is a fair increase)

 

[Chester Gunn]

Guys, I went out and tried it again this morning...and at first, it wouldn't start.. And remember, the carb synch screws have all just been replaced, and the bike is definitely not synchronized....and I didn't really have a place to start, so I kind of went "half way"...then "all the way"..once I backed them out a little this morning, the bike started...but it never would idle up..It was acting like it was starving for fuel, as it would only running when the choke was fully engaged.. I"m wondering about the idle adjustment...Yes, like an idiot, I did mess with that a couple of days ago when it was idling so high...but that adjustment had no effect on the idle..and I've turned it a bunch..in both directions..Can you tell me which direction I should turn this screw to increase the idle??

 

[physics-teacher]

Turn it clockwise to increase idle speed. A small adjustment ordinarily makes quite a difference. Sound like you need a shop or Clymer manual. A sweet running 650 is a joy (forever?)

 

[Chester Gunn]

Turn it clockwise to increase idle speed. A small adjustment ordinarily makes quite a difference. Sound like you need a shop or Clymer manual. A sweet running 650 is a joy (forever?)

Believe it or not, I've got a clymer manual...and I've studied it....It will run, it just won't idle....but it was idling before I them off of the bike...and I didn't touch anything internally in the carbs...just replaced the synch screws..and of course the idle adjustment....

 

[Chester Gunn]

And the only way it will run is when the choke is engaged....which must mean it's not getting fuel, right?? But, no kinks in the fuel lines...all cylinders are firing...fuel in the fuel filter....

 

[mike-s]

Well something to try when you first put the carbs back together is to do a "preliminary" synchronise, whereby you use a mechanical item such as a thin length of wire or a watchmakers screwdriver (they go as small as 1.5mm - 1/16th inch or so) and you set the "primary" carby (the one that the throttle body is connected to) to just touch the wire/screwdriver when you pass it under the edge of the throttle butterfly. Next up you measure up the neighbouring carbs and work your way out. Once you've got them all checked, give it a final check to make sure they're all as close as you can get them mechanically.

Next step is to refit the carbs to the engine and start her up and move the idle setting out until it reaches a point where the carbs are closed enough that she is idling by herself at a preferred rev range.

Oh and to move the idle down just remember the idle screw is like any other right handed screw and is clockwise to screw in (or in this case revs up). So from behind the engine, facing the front of the bike, increasing the revs is a case of screwing it in in a clockwise motion.

 

[mike-s]

And the only way it will run is when the choke is engaged....which must mean it's not getting fuel, right?? But, no kinks in the fuel lines...all cylinders are firing...fuel in the fuel filter....

Mechanically set the balance on the carby's and then start her up. some bikes are rather cold blooded and need a hand from the choke to work at all at anything below fully warmed up. Others work fine and the choke is really just there for decoration. A safe bet is to go 1/2 choke and get her fired up so you can finalise the settings yourself. Just remember wait until she is warmed up before you get the carbs balanced.

Just remember you have to find the balance of how much choke to use when starting her, some bikes are fiddly, others couldnt care less what you do. My bike likes 2/3 to 3/4 choke when she's cold, no more, no less, and no throttle needed, she just wont go when any is used.

 

[LarryA_Texas]

petcock:

petcock:

I'm thinking that even a bad o-ring isn't going to make it run fine one day and then shoot up to 4000rpm. Sure, they could be bad, and probably are. But that's not a common symptom of o-rings.

I might start by thinking the petcock got a leak on the diaphram. excess fuel could be running down the vacuum tube into the no. 2 carb. You take both hoses off the carbs and check that fuel runs out the big hose when it's in prime. Then make sure none comes out in either run or reserve. Now, suck gently on the smaller hose and confirm that no fuel is coming out of the smaller hose...none at all...never. It's just for vacuum. As you suck on the small hose fuel should run out of the big hose.

Once you confirmed petcock operation take a close look at the throttle cable. If it's binding anywhere re-route it so it's not crimped. Then look at where it mounts to the carbs. There should be a little free play. Sometimes if they're mounted with no play the cable itself can be pulling the throttle open a tiny bit. This really shows up when you turn the handlebars and the it revvs up.

Then take a look at the throttle movement on all the carbs. I've seen loose screws or even a wandering clamp get in the way and restrict the throttle movement so the rpm's won't settle down. Also make sure the choke isn't binding or stuck open.

After you've done all that, now you're back to carb removal and inspection. The idle screw is one screw on the bottom of the carbs. Those little mixture screws are on the top; one on each carb sealed at the factory by a plug. If you can see them they've been drilled out by a PO. Those wouldn't cause the symptoms you describe, either, but if you've turned them it will affect how it idles and runs. They should go back to factory settings as you start to trouble-shoot the other RPM problem.

Hope this helps.

 

[waterman]

Very sound advice. I too wonder at the onset of the problem, it sounds like excess fuel. I had one of my 650 develop the same trouble with a screaming motor. Turned out the previous owner had incorrectly installed the carb slide. This prevented the slide from fully closing and the rich condition. Not saying this is what is wrong with yours but a possibility if the carbs were "fixed" by someone else. My bet is that your petcock and carbs are a little leaky.

As for the carb boots, if you can get a pair of vice grips (small size, Vice grip brand) and firmly attach to head of screws like you would to remove a bolt head, you can break the screw free. Once you get one screw removed, use a drift punch and hammer to free the other screw by tapping the whole metal boot counter clockwise. This usually will break the screw loose. A hammer driven impact screwdriver is the best tool to remove all of the screws on the motorcycle, it however is a pain in the arse to get into the area to remove the carb boots.

I didn't see whether you have cleaned carbs and/or replaced orings in carbs? Would hate to pull carbs and replace without at least pulling bowls to make sure they are clean.

Stick with it, we have all been there before. Wish I could be there to help, beats work today...

 

[Chester Gunn]

Thanks to all you folks for the kind advice.. I'll definitely have plenty to consider this weekend while I'm "turning wrenches"...or maybe I should say, being "turned by wrenches"... I sincerely thank each of you for taking the time to respond....Be ready for more questions..

Best regards,
Chester Gunn/Chula, GA

 

[Guest]

I bet the throttle cable is pulling the carbs open. See if the cable is bound somewhere or routed wrong.

 

[Suzuki mad]

I'd go for a stiff carb cable or the butterflies stuck open. If its a 650 then it should be CV carbs.

Suzuki mad

 

[Chester Gunn]

Update..

Update..

Well guys, I wanted to give all of you an update...I still haven't been able to get the old gal running very well.. When I went out back the last time, I had one hell of a time even getting her started...and after she started, she wouldn't even think about idling..In fact, she really wouldn't even rev up very much...totally dependent on the choke..I backed the synch screws off just a bit, and she fired right up....and then died again..I got her started again, and she revved up very high, and then died...It's almost like she's not getting any fuel, unless she's being choked. I was trying to run it off of the tank, but finally went back to my external fuel tank,thus bypassing the petcock and I know that the gas is flowing...and I pulled one of the plugs...and it did seem a little bit dry...not terribly, but a little bit..

I wouldn't have thought that the synch screws would have had such a large bearing on whether she runs or not.. I thought that it might run a little rough, but at least run.. I did notice that the p.o. had removed the caps on the air screws...and I haven't touched them..

So, I guess it's just more trial and error unless someone can come up with another suggestion...and belive me, I'm all ears... We will get this thing running!!
Thanks for your help,
Chester Gunn/Chula, GA

 

[LarryA_Texas]

start over

start over

Well guys, I wanted to give all of you an update...I still haven't been able to get the old gal running very well.. When I went out back the last time, I had one hell of a time even getting her started...and after she started, she wouldn't even think about idling..In fact, she really wouldn't even rev up very much...totally dependent on the choke..I backed the synch screws off just a bit, and she fired right up....and then died again..I got her started again, and she revved up very high, and then died...It's almost like she's not getting any fuel, unless she's being choked. I was trying to run it off of the tank, but finally went back to my external fuel tank,thus bypassing the petcock and I know that the gas is flowing...and I pulled one of the plugs...and it did seem a little bit dry...not terribly, but a little bit..

I wouldn't have thought that the synch screws would have had such a large bearing on whether she runs or not.. I thought that it might run a little rough, but at least run.. I did notice that the p.o. had removed the caps on the air screws...and I haven't touched them..

So, I guess it's just more trial and error unless someone can come up with another suggestion...and belive me, I'm all ears... We will get this thing running!!
Thanks for your help,
Chester Gunn/Chula, GA

Ok...start over from the beginning. It was running great, the suddenly the idle shot up to 4000rpm? Now it won't start? Is that right? There are a lot of possibilities. If you know the throttle cable isn't sticking then start with the carbs.

Take them off and make sure the float needles are all working properly. There is a possibility that the 'normal' idle was with three cylinders and when #4 fired up that was the increased RPM. Not likely, but possible. Once you know all 4 bowls are getting gas then make sure the needles/slides are not sticking. Clean them with carb cleaner and make sure they are sliding easily. Check the filter while you're there. Excess oil?

Under the float needles-you know you have to take the floats off to get at them-pull out the float needle valve assembly and make sure the screens are clean.

If you still are not having luck you will have to Remove the choke assembly and start to look at o-rings. There are rings in the float valve assembly, on the choke, and little tiny ones on the fuel/air screws. Once you replace all of these you've pretty much disassembled the entire carb. Refer to the carb rebuild guide on this website for details with pictures.

good luck.

did you check the petcock for normal operation? Make sure that's right.