Idle issues, I'm on my last straw

[Guest]

First of all I'm almost embarrassed to bring this up in a new thread. One might think that all that has been said about this in the forum would help me, but no.
The bike is a -81 GS450E, stock except pod filters, european version with mechanical ignition (points) and adjustable needle and mix. screws.

The bike has been gradualy brought back to life over the past years, with the help from this forum.
The problem is: I can't get it to idle right.
This problem has sustained during the entire restauration proscess, but was initally hidden by other more serious problems. The bike has EMGO pod filters, as the PO had mangled up the airbox beyond repair, and this was the cheapest fix. (I was a student at the time)

The pods are working ok, it was some struggle to get the right jetting, but that has now been cleared.

The symptoms are classical intake leak symptoms. It will not idle when cold, and if I adjust the idle knob to where it is idling ok, it will reach 4k -5 k rpm when hot.
The carbs have been dipped, cleaned, I've changed the rubber on them, the intake boots are ok, o-rings are new, float levels are spec. and they are synchronized. Everything seems to be in order, but it's still not right.

Last night I did the water mist test, this had no effect until I overdid the mist on the pod filters, and it turned out that this bike does not run on water.

What got me pondering late last night, after I gave up, is that this problem has been with me during the entire restauration process. To me this would indicate that the problem lies somewere where I have not done anything.

The bike has no electrical gremlins, but what problems with the igniton/electrical could cause this situation?

Any thoughts are appriciated, as my imagination on this is running dry!

[gsBert]

are you using the choke to start it cold?

keep the choke on until it warms up...

[redliner1973]

Also, are you oiling the pod filters? if so, with what?

[KEITH KRAUSE]

Sounds like an intake leak as you said. Also sounds like you've checked the parts that usually cause this problem. All clamps are tight and you can't rotate them after tightening? You're sure the manifolds and o-rings are correctly seated and torqued to about 6 ft/lb? Manifold o-rings are new, correct size as originals and some hi-temp grease was applied? Are your manifolds identical or could you have swapped them wrong? Any signs of a head gasket leak? Have you torqued the head down recently? Did you torque the bolts in the correct pattern?
Have you REMOVED THE FLOATBOWL VENT LINES? Some very erratic idling problems can occur by running pods with the two vent lines still attached. Generally causes fuel starvation. Remove them, leave the ports open, and test. Won't take long at all to see if this helps. If it does help, leave the ports open. Just be careful if you wash the bike with a hose.
Even if it doesn't help, leave the lines off.

[Buffalo Breath]

hi-r's

Check your ignition advance unit it may be sticky and not returning all the way,or the springs may be shot, also check the throttle shafts if they have a lot of play in them they may be causeing the problem even if you syn. the carbs, the shaft busings or bearings are more than likley the cause.

[blo]

Thank you, all. This was the kind of brainstorming I was hoping for. As to what has been tried of this:

Clamps are new, stainless and well tightened.
O-rings are original suki spares. Identical to the ones I took out.
Engine, including head and valves, had a makeover less than 5000 km (3100 mi) ago, head has been retorqed once after assembly.
Vent lines no longer installed (was removed when installing pods)
Throttle shafts are tight, springs are good.
Pod filters are oiled. If not otherwise supplied, I use motor oil, but not much.

As I'm quite the gadget head, I have a full supply of torqe wrenches, synch.tools, timing guns etc. I try to do the most myself. The point about ignition was interesting, I think I will take out my timing gun this weekend, and see what comes out of that.

Thank you, again.

[IanFrancisco]

Re: Idle issues, I'm on my last straw

Last night I did the water mist test, this had no effect until I overdid the mist on the pod filters, and it turned out that this bike does not run on water.

I've read on other forums about guys who use WD40 instead of water to do the intake leak test. Idle increases instead of decreasing. I haven't tried it myself so YMMV.

[KEITH KRAUSE]

Re: Idle issues, I'm on my last straw

Last night I did the water mist test, this had no effect until I overdid the mist on the pod filters, and it turned out that this bike does not run on water.

I've read on other forums about guys who use WD40 instead of water to do the intake leak test. Idle increases instead of decreasing. I haven't tried it myself so YMMV.

Right. But why would you spray a messy oil on your motor, that's potentially flammable and not good for rubber (especially where you can't easily wipe off the excess), when you can spray a water mist that disappears with the heat almost immediately?
Also it's easier to hear a small/abrupt rpm drop than a small rpm gain. Though the rpm drop/gain can be different according to the leak. Just my opinion.

[flyingace]

Won't run on water, eh? Too bad - you coulda been rich enough to buy Suzuki.

Do you have compression readings on your bike? Do you have any places where the head gasket maybe leaks? This sounds like an intake leak, but the bases appear to be covered.

Ace.

[gspaul]

Did you change the condensor/s in the ignition?

[LW_Icarus]

Canned Air for cleaning a computer works to find intake leaks as well, and is perfectly clean. I spend too much time removing old crud to even think about spraying new crud on it :P

Im only mentioning this because of my experiences today, and how similar our situations seem (I have a fresh engine, and have been very pro-active in the repairing of my bike). it ran fine, seemed to idle fine when warm, but cold fell on its face, or screamed on the choke.

I had it in the shop and an old mechanic there ran the wire from a wire brush through my pilot jets,I had sprayed and soaked and blown through them a few times, you could see light through it, little did I know it was so restricted.

when he reinstalled, and fired it up my throttle opening was way to big, like 3000 rpm worth, set that down and it purrs. with the much lower idle settings it should run better on choke too. Ill know in the morning when I go to work

my mixture screws are accessible now (don't tell the EPA ) and with a little tweaking it falls to an 1100 rpm idle stable as you please, warm and hot.

I woulda beat my head against a wall indefinitely had I not had this mechanic look at my bike, he's been working there since my bike was made, so I guess he knows his stuff. I know my bike is transformed.

[KEITH KRAUSE]

I woulda beat my head against a wall indefinitely had I not had this mechanic look at my bike, he's been working there since my bike was made, so I guess he knows his stuff. I know my bike is transformed.

No need to beat your head, we're all learning here.
Not trying to toot my own horn, but in my replies to your topic/problem, I first said the pilot circuit was dirty, then I said to synch the carbs followed by a vacuum synch, then adjust the mixture screws.
So you had the right info all along, your biggest problem was not completely cleaning the pilot circuit, which happens very often. Now you know how clean these small passages have to be and the extra effort needed to be sure of it.

[LW_Icarus]

No Keith, don't misunderstand, your help was all good, valid, helpful and appreciated. and you were indeed correct. and I am pretty sure you would've fixed the problem as quickly had I been able to get my bike to your garage.

but without knowing myself how big the orifice is suppose to be I (mistakenly) presumed it was clean when I could see light through it. I suppose I eventually woulda thought to ream out the hole a little, maybe. but I was always under the impression that wires through a jet was BAD.

no need to toot your own horn, I absolutely appreciate your input (education) and have read alot of the older posts from you and a few other of the GS gurus around here, and it has helped me immensely throughout the rehab. your help has been invaluable, and sometimes entertaining

Anyway, Keith you are a great asset, many many thanks from me both for your specific help with my problem, and your general help that Ive gleaned from other topics you've helped with. I was thinking the other day about how many GSs are on the road that otherwise wouldnt be if it wasnt for this forum and the associated cast of characters, I'll bet its triple digit. any time I was getting frustrated I got on here and started reading, and eventually could get excited about the project again. I wouldnt have given up no matter, but it helps.

[KEITH KRAUSE]

Yes, living with older bikes can be a challenge. But as you pointed out, (and what used to be my signature) don't give up, don't get frustrated, you're not alone.