Still Won't Idle! I think I'm done.

[Commodus]

Note that I often find the choke plunger areas on these carbs to be problematic. Try the WD40 trick there, especially.

 

[bonanzadave]

Even tho you have new fuel and vac lines make sure the vac line is not kinked or is to thin walled and is colapsing under vacuum. Once the tank is on its like the old refridge light and the door. Does the light go off when the door is shut ? I guess if you ran it on the "pri" position it would eliminate the bad vac line possibility. Good Luck.

 

[KEITH KRAUSE]

The bike will start very quickly with full choke and idle at 900rpms. The rpms will then start to climb and reach around 2900rpms and stay there for about ten seconds, at which point the rpms will begin to fall until the bike stalls. No amount of messing with the choke will prevent her from stalling.

If I walk away for about 2 minutes or so and then attempt to start it again, she'll start right away with no choke and idle at 1100rpms, albeit not very strongly.

Now, when she's beginning to stall, I can prevent it by giving her light throttle and holding the throttle on for about a minute or two, at which point she'll idle on her own with no choke. But again, it's not confidence-inspiringly strong.

When riding, if I pull in the clutch and hold it, she'll often stall out on me. More often than not, actually, until I get her warmed up.

When she's FULLY warm, her idle jumps about 800rpms to 2000.

Just saw this as I'm going to bed. So just a quick thought.
Sounds like an intake leak. I know you say the manifolds are new.
Are you positive they're the correct ones? Are they genuine Suzuki? Does each manifold have to go at a specific cylinder on your model? Are you using the factory style clamps?
Barring an intake leak, the only other thing that can cause the rpm's to rise incorrectly as you describe is the diaphragm/spring assembly operation. Do you know if the springs are installed correctly and are they stock or look like they've been changed or modified by a PO? Are they colored?
Seems like your symptoms are a combination of two problems. Sure seems like an intake leak is involved though. An intake leak will cause the choke to have limited effect. An intake leak also starves the bike because the loss of vacuum means less fuel drawn up, most noticable when still cold/warming up. Stalling is then common. Once hot enough, the intake leak increases the rpm's and the bike can't stall even though the intake leak is creating a lean condition.
Just wanted to ask you the above. Maybe we can narrow this down. It's late, gotta get to bed.

 

[UncleMike]

Just saw this as I'm going to bed. So just a quick thought.
Sounds like an intake leak. I know you say the manifolds are new.
Are you positive they're the correct ones? Are they genuine Suzuki? Does each manifold have to go at a specific cylinder on your model? Are you using the factory style clamps?
Barring an intake leak, the only other thing that can cause the rpm's to rise incorrectly as you describe is the diaphragm/spring assembly operation. Do you know if the springs are installed correctly and are they stock or look like they've been changed or modified by a PO? Are they colored?
Seems like your symptoms are a combination of two problems. Sure seems like an intake leak is involved though. An intake leak will cause the choke to have limited effect. An intake leak also starves the bike because the loss of vacuum means less fuel drawn up, most noticable when still cold/warming up. Stalling is then common. Once hot enough, the intake leak increases the rpm's and the bike can't stall even though the intake leak is creating a lean condition.
Just wanted to ask you the above. Maybe we can narrow this down. It's late, gotta get to bed.

My bike takes the same manifolds for all four and they're genuine Suzuki, although the bike was doing this before I changed them as well.

The springs are installed correctly and they do not look as though they've been changed or modified. As far as I know, I'm the first person to have taken apart the carbuerators. The springs are not colored.

No amount of spraying has ever indicated an intake leak.

I appreciate your help, Keith. Thanks.

 

[KEITH KRAUSE]

My bike takes the same manifolds for all four and they're genuine Suzuki, although the bike was doing this before I changed them as well.

The springs are installed correctly and they do not look as though they've been changed or modified. As far as I know, I'm the first person to have taken apart the carbuerators. The springs are not colored.

No amount of spraying has ever indicated an intake leak.

Well, it sure sounds like the manifolds are OK. Only you would know if the carbs are positioned correctly into them and the clamps positioned and tightened correctly. I assume they are.
I'm not sure why you believe the carbs have never been taken apart but I'll have to assume you're right on that too. If so, the diaphragm/spring assembly should be fine since a failure here usually means a lack of throttle response or none at all instead of your high rpm problem.
So you've inherited the problem? No amount of carb or electrical work has any effect.
Have you ever taken a compression read? I'm thinking you may have a leaking head gasket. Has it been replaced or at the minimum, re-torqued correctly? Any visible signs of a leak anywhere?

 

[UncleMike]

Well, it sure sounds like the manifolds are OK. Only you would know if the carbs are positioned correctly into them and the clamps positioned and tightened correctly. I assume they are.
I'm not sure why you believe the carbs have never been taken apart but I'll have to assume you're right on that too. If so, the diaphragm/spring assembly should be fine since a failure here usually means a lack of throttle response or none at all instead of your high rpm problem.
So you've inherited the problem? No amount of carb or electrical work has any effect.
Have you ever taken a compression read? I'm thinking you may have a leaking head gasket. Has it been replaced or at the minimum, re-torqued correctly? Any visible signs of a leak anywhere?

I don't believe they've ever been taken apart because they still had the plugs over the mixture screws, and none of the screws had any wear at all on them from being taken apart. Just a guess though, and trusting the P.O. when he said they'd never been apart. Stupid, I know.

I've not taken a compression read, but it's my next step. I've just to locate the correct adapter to fit in the plug holes.

The engine weeps oil in several places, but never enough to drip at all. Just get a bit moist. I've tightened some bolts, but not a proper re-torquing.

 

[KEITH KRAUSE]

I'd first try re-torquing. Wouldn't hurt.
I'm not sure what your head is supposed to be torqued to. It's more precise than most other bolts. Check before torquing. Don't just guess. Use a good torque wrench.
Crack loose the bolts just a little before re-torquing. You can't accurately torque a bolt without loosening it a tad first. The threads should be clean too but I'm not asking you to remove and clean, just crack and re-torque. Hopefully that will be all that's needed.
Do on a stone cold motor. Gradually torque all bolts/hardware in a criss-cross/diagonal pattern, starting at the center and working your way outward. Example: if you have 12 nuts, "top" row is nuts 1 thru 6, bottom is 7 thru 12, sequence would be 4, 9, 3, 10, 2, 11, 5, 8, 1, 12, 6, 7. Torque any outer/smaller (10mm?) bolts last, after the other larger nuts/bolts. Make sure you locate/torque all the small bolts.
Test to see if it helped.

 

[argonsagas]

I read most of these, Mike, and a simple response came to my simple mind.

Have you balanced all the butterflies? All you need to do (with arbs OFF) is back off the idle screw completely, then look at the butterflies. All should just barely contact the side of the carb. A piece of newsprint can be used to check the closing: if it just sticks, and can still be pulled free, on every valve, you have it right.

I had a similar problem, and fiddled around with cleaning and mixtures until I finally found that solution.

 

[UncleMike]

I'd first try re-torquing. Wouldn't hurt.
I'm not sure what your head is supposed to be torqued to. It's more precise than most other bolts. Check before torquing. Don't just guess. Use a good torque wrench.
Crack loose the bolts just a little before re-torquing. You can't accurately torque a bolt without loosening it a tad first. The threads should be clean too but I'm not asking you to remove and clean, just crack and re-torque. Hopefully that will be all that's needed.
Do on a stone cold motor. Gradually torque all bolts/hardware in a criss-cross/diagonal pattern, starting at the center and working your way outward. Example: if you have 12 nuts, "top" row is nuts 1 thru 6, bottom is 7 thru 12, sequence would be 4, 9, 3, 10, 2, 11, 5, 8, 1, 12, 6, 7. Torque any outer/smaller (10mm?) bolts last, after the other larger nuts/bolts. Make sure you locate/torque all the small bolts.
Test to see if it helped.

Keith,

I can't tell you how much I appreciate you taking the time to actually go through a theoretical sequence for me. I would have second guessed myself the entire time otherwise. I'll let you know if it helps, and thanks again.

Mike

 

[UncleMike]

I read most of these, Mike, and a simple response came to my simple mind.

Have you balanced all the butterflies? All you need to do (with arbs OFF) is back off the idle screw completely, then look at the butterflies. All should just barely contact the side of the carb. A piece of newsprint can be used to check the closing: if it just sticks, and can still be pulled free, on every valve, you have it right.

I had a similar problem, and fiddled around with cleaning and mixtures until I finally found that solution.

So, they shouldn't be closed completely with the idle screw off? You're talking about the throttleplates, right?

 

[r.t.snake]

works for me

works for me

Hi Mike,

I had a similar problem with my 550 and posted my best wishes a couple days ago.

Well your posts got me back at it.

It seemed that over and over the suggestion was that all indications were an intake leak. BUT - there was no intake leak. I tried all the usual suspects, and it sounds like you have done the same, so...


IF intake leak = lean condition

what else could make it lean?????

- not enough back pressure seemed like it might be a possibility so I took off my not stock mufflers and shoved on the old beat up megaphones and VOILA!

idle doesn't run up-
a little throttle then the idle falls and doesn't stall

oh happy day!

Don't know if that works for you but it sure made my day I'll tell you!

Good luck,

RT

 

[UncleMike]

Hi Mike,

I had a similar problem with my 550 and posted my best wishes a couple days ago.

Well your posts got me back at it.

It seemed that over and over the suggestion was that all indications were an intake leak. BUT - there was no intake leak. I tried all the usual suspects, and it sounds like you have done the same, so...


IF intake leak = lean condition

what else could make it lean?????

- not enough back pressure seemed like it might be a possibility so I took off my not stock mufflers and shoved on the old beat up megaphones and VOILA!

idle doesn't run up-
a little throttle then the idle falls and doesn't stall

oh happy day!

Don't know if that works for you but it sure made my day I'll tell you!

Good luck,

RT

Congratulations! Go for a ride!

Unfortunately, I've got the stock exhaust on and the thing is pristine. Looks almost brand new.

I suppose I could cover the ends and see if that helps at all.

Thanks, and congrats again.

Mike

 

[r.t.snake]

Too bad it was not a solution for you ,

Good luck!

RT

 

[UncleMike]

Too bad it was not a solution for you ,

Good luck!

RT

I appreciate it regardless. Thanks!

Mike

 

[Billy Ricks]

Just a longshot here, but you might want to try retorquing the head. Could be a slight leak between the head and the block. Look closely at that area and see if there is any ooze there.

 

[UncleMike]

Just a longshot here, but you might want to try retorquing the head. Could be a slight leak between the head and the block. Look closely at that area and see if there is any ooze there.

Sure is. Keith mentioned it as well. Gonna grab a torque wrench tomorrow and go for it.

Now, there is a general consensus as to what type of torque wrench is best, right?*

Mike

 

[Billy Ricks]

Sure is. Keith mentioned it as well. Gonna grab a torque wrench tomorrow and go for it.

Now, there is a general consensus as to what type of torque wrench is best, right?*

Mike

Do you have a manual Mike? You want to do it in the right sequence. It's a good idea to back them off a tiny bit before retorquing.

 

[UncleMike]

Do you have a manual Mike? You want to do it in the right sequence. It's a good idea to back them off a tiny bit before retorquing.

I've got a Clymer's. Plus Keith gave me a pretty good tutorial a few posts back. Just need to find the torque specs in the manual.

Thanks Billy. I appreciate you sticking with this madness.

Mike

 

[Billy Ricks]

I've got a Clymer's. Plus Keith gave me a pretty good tutorial a few posts back. Just need to find the torque specs in the manual.

Thanks Billy. I appreciate you sticking with this madness.

Mike

Just hang in there Mike, you'll get it figured out.

 

[Billy Ricks]

Mike, if retorquing doesn't help I'd be happy to go through the carbs for you gratis if you think they might be the culprit.