3 questions after carb rebuild

[Anonymous]

1980 GS850GL: I just recently rebuilt the carbs on this bike. I put it back together but having a hard time starting and it wants to flucuate in idling.
I took this bike to the shop to which they took the carbs off and apart (again) to make sure I did and put all parts where they belong. And they put it back. Now the questions are.

1) Do you who have this same bike find it hard to start when the weather is below 50-55 degrees (cold blooded)? I have always had to use starter fluid when its below 55 and was hoping this would change when rebuilt, but not.

2) After the bikes warms up and you can turn the chock off. She idles at about 1000-1200 rpms. I can run it about 3 miles and when I come to a stop sign and now in first or neutral she is idling at 2500. I get off and turn the idle stop bolt until about 1000. and I have done this 3 times in a ride. Now the bike runs great except for this. Why is she doing this and what do I do. The mechanic does not seem to know and says to keep turning back the idle stop bolt until she stops doing this and it (depending on how often I ride) will take a bit to get her right. Does this sound right?

3) Do these bikes run hot? After my ride to work about 45 minutes you can feel the heat rising off the bike. Is this normal?

Thanks cj

 

[lukehan]

o-rings

o-rings

From personal experience and posts in this forum it sounds to me like you should check the o-rings between the cylinder head and the rubber carb boots (that connect the carbs to the engine). Might have an air leak there causing lean (hot) running and high idle as well as hard starts.

Luke

 

[Anonymous]

intake o-rings

intake o-rings

I have them but I could not get the screws out even with an impact.
So needles to say they did not get changed.
I could get to the two outer ones top to do an ez-out but not the rest.

 

[Detman101]

Sounds like for whatever the reason is....you are running lean.
You may have leaks in some parts of your intake or your fuel mixture screws may be out of adjustment. That would also account for your hard-starting on cold days.

Dm of mD

 

[Hoomgar]

Cj, you gotta get those boots off and check them. If they have o-rings replace them. Use some hi-temp bearing grease to help them seal. If you just cannot get them out then you will have to drill them out. If you drill with a larger bit and just drill off the heads then you can pull the boot off and now be able to get at the stud left sticking out with some PJ or a good penetrate spray and even some heat if needed.

All your carb work is in vein and for nothing if those intake boots are leaking air in.

 

[snowbeard]

with my boots, I had no room to access the middle one's either. I was able to use just the #3 (great big :wink: ) hardened steel philips bit alone, I'd set it in the screw, and tap it lightly with a hammer, then give it two or so good whacks, then use an adjustable wrench on it, bracing the fulcrum so it didn't tweak the bit sideways and out, and they broke right free?

maybe give it a shot before you drill, but it may not help anything, but I doubt it'll hurt!

either way, ya gots ta get those off!!

 

[AOD]

Did you sync the carbs??

 

[Anonymous]

carbs

carbs

yes the carbs were sync'd.

 

[Wingnut]

I had to get my intake screws out also. First you have to give them a good wack! (or two or three) I use a philips apex in a 1/4 inch drive deep socket and wack it good. Then put some valve grinding compound on the apex tip and use the 1/4 in drive rachet to try to get it out. You can't believe how much better grip you get using valve ginding compound. Another alternative, if you have the room is to get on the head of the screw sideways with a small good quality pair of vise grips real tight. That works good too but it buggers up the screw some.

 

[KEITH KRAUSE]

Like others said about the high idle once warmed up..it's definitely the manifolds or the o-rings in them, or if you're lucky, loose manifold clamps.
Try tightening the clamps first. Make sure they're centered in the flat indentation meant for them. If it still leaks, check the manifolds for cracks/hardening. It's the o-rings inside more often than the manifolds though.
All 3 of your problems sound intake leak related.

 

[bradleymaynar]

Get your hands on an impact screwdriver (Check Harbor Freight if there's one nearby). A couple of taps and it should be able to break the screws free. Spraying them with PB Blaster or Marvel Mystery Oil would definitely help.

Brad tt

 

[AOD]

I'm slightly against jumping on the bandwagon that if your idle raises when it's warm the intake boots are the cause. I have transfered a rack of carbs between two GS550's and the 500-600 RPM idle speed increase followed the carbs. Ryan (firsttimer) even did the propane test when the bike was running, and the idle never changed.

Currently my bike idles at 1500 when cold, off choke, and 2000 RPM when warm. I don't idle a lot, but even when I did, I enjoy the higher engine speed.

My thoughts are it's probably the fuel to the engine stays the same, but as the temp rises it burns easier and sticks less to the cold walls of the combustion chamber. It may affect the idle...

~Adam

 

[back_online]

I rebuilt my carbs twice and had the same problem you do.
I rebuilt last month, FINALLY replaced those dreaded 4 o-rings eveyone is talking about. And for the first time in 4 years, the bike's idle stays the same (once warmed up) no matter if I've rode hard for hours, or she's been stuck in traffic.
The carbs are quite involved, and you could have many other small problems. But I suggest changing these pesky leaky o-rings.

Good luck to you.

 

[KEITH KRAUSE]

I'm slightly against jumping on the bandwagon that if your idle raises when it's warm the intake boots are the cause. I have transfered a rack of carbs between two GS550's and the 500-600 RPM idle speed increase followed the carbs. Ryan (firsttimer) even did the propane test when the bike was running, and the idle never changed.

Currently my bike idles at 1500 when cold, off choke, and 2000 RPM when warm. I don't idle a lot, but even when I did, I enjoy the higher engine speed.

My thoughts are it's probably the fuel to the engine stays the same, but as the temp rises it burns easier and sticks less to the cold walls of the combustion chamber. It may affect the idle...

~Adam

Carbs are all built the same, for the same model. There's no way one set just happens to idle at 500-600 rpm's higher than the other set, unless they've been set up wrong. If the rpm increase you have isn't carb related, then you have an intake leak or the smaller chance that a slide is sticking with the heat increase. The VM's do that once in awhile.
If your bike idles at 1,500 cold and 2,000 warmed up, you have one of the above problems. No Suzuki model in the 70's has a factory set/recommended idle of 1,500 rpm's. Nor the CV equipped bikes later. The correct idle speed for our bikes is 900-1,100 rpm's. If your idle is set at 1,500, you'll use more gas, wear out your brakes sooner, it's harder on the clutch and gearbox too. It also makes your bike tend to overheat at stops in traffic.
A correctly jetted/tuned bike will start up and idle about 1,000 rpm's, and then pick up about 100 rpm's once warmed up with no other outside influence (elevation, humidity...). Some may pick up a little more, maybe to 1,200.
What's this propane test you talked about?

 

[Guest]

To get the screws out, try a pair of channel locks, a bottle of beer, and a lot of patience. I just changed mine (see the posting "carb boots"). New boots will make a world of difference.

 

[duaneage]

Cut a slot in them with a dremel tool if you can. I used a SMALL vice grip that I found at pep boys to get mine off. And 10 mm hex head bolts replaced them. Torqued to 6lb/foot.
Replacing the o-rings was the best thing I did to my bike. Throttle response and torque went WAY up.

 

[Anonymous]

I just had my carbs rebuilt on the gs750t. The intake boots are not part of the engine just rubber seals that go between carb and engine. These boots are new and my bike does this. Idles perfectly between 1100 and 1500 and then when I ride for 20 minute idle goes up to 2000.

 

[Anonymous]

in my search I found

in my search I found

well in my on going search, cease and fix on this carb rebuild and Idle problem I found two things.
I bought new boots between the carb and air cleaner, to which I have installed. But when I went to get the o-rings for the manifold boots the suzuki parts manager said he may have sold me the wrong boots.
I have a glt model and he said he looked up the boots for a t model (which there is a $14.00 difference between what I got and should have gotten. I paid 10.98 per boot and they said I should have had the ones for $24.95 per boot). Now I have the old boots I took off and they look exactly like the boots I have so what is the difference that would make them so much more? The reason I ask is since I have installed these boots they will not give me credit towards the new one, even though its their fault and not mine.

2) I found a small leak in the breather gasket and cam gasket (so I have to replace them). Can this cause this problem with hard start and vering idle also?

thanks cj

 

[Jethro]

What's this propane test you talked about?

Keith, he must be talking about an intake leak test- some people use water mist to check for a loss of combustion, some use flammable materials to check for an increase in idle. I use WD40 or carb cleaner.

The reason I piped up about it is becasue I had an air leak that this test didn't work on. I had cracked boots, but no amount of water, WD40 or carb cleaner would show a change in idle. I still changed out the boots and the bike started, idled and ran much better.

 

[KEITH KRAUSE]

That's right. I always try to mention in my posts that the water mist test, or whatever is used, doesn't always expose the leak. But the high idle problem is about 98% of the time an intake leak in the manifold area. About 1.5% of the time, it's a sticking slide/throttle valve. The other 0.5% is gremlins.