Tell me if this makes sense

[drhach]

I've been working on carb issues on my GS1000 for quite some time now. I started with pod filters and 4-1. I them put the stock airbox back on with a K&N air filter which I initially over oiled. So, during the jetting and "discovery" process, my ignition system went south, giving me false readings on my jets (the plugs looked rich because they had no spark). Much hair was pulled out. The outcome of this is that I have replaced all of my ignition system, including adding a Dyna S and new plug wires and caps (I still have the coils). I checked the valves (again), I replaced all intake boots with KZ boots, re-cleaned the carbs, cleared all openings with compressed air and verified they were clear with compressed liquid.

I currently have jetting as follows:
Pilot=17.5
Main=100

Also:
-Vaccum tube to petcock is plugged to rule that out.
-Plugs all look good and all look similar for all ranges
-Carbs are properly synced and spot-on
-No Hysteresis in throttle cable


The bike runs fantastic, it idles at 1000 RPM (which wouldn't do before). However, when the engine gets warm, the idle hangs. I am sure that everything is tight and right, but "the proof is in the pudding" as they say. The idle hangs. My theories on why this is happening have become more and more esoteric and I'm trying to get back to what is probably a simple solution.

So here is what I'm thinking and I want to check to see if my theories and premises make sense. So, correct me if I'm wrong on any of these points.

1. The nipple (I love that word) where the breather tube goes in to the airbox is broken and leaks profusely. However, this should not cause the idle to hang. Should it?

2. If the system is truly sealed as it should be, then if I plug the two intake holes at the bottom of the airbox behind the right side cover, the bike should die (assuming I fix point #1).

3. The system can be broken in to two parts
a. The airbox and all parts before the carbs
b. All parts after the carbs
c. Nothing in the carbs could cause a vaccum leak that would lead to a hanging idle so they are not a part of the system that needs to be considered.

So here is what I'm thinking. I should be able to attach vacuum gauges to the engine, warm it up and rev it. When the idle hangs, assuming that the leak is between the carbs and the head, I should see a discrepancy in one or more of the gauges. The hanging cylinder should have (much) lower vacuum than the others. That cylinder will be the culprit and the solution MUST be the intake boot seal. If they stay the same, the issue is in the airbox.

Also, I may be wrong about the broken nipple. I can't conceive how it would cause the idle to hang, but I will seal it all the same. Also, I put weatherstripping around the lid already; no cahnge.

[BadBillyB]

Can you elaborate on "KZ boots"....Does that mean new or used....Suzuki boots use an "O" ring for better seal....Hanging idle is usually from a lean mix. but your jetting sounds perfect....Billy

[Big T]

You can use the KZ intake boots in place of the Suzuki ones. They can be less expensive and they have a built in sync port (good for smoothbores)

The handing idle is due to an air leak. I notice you don't state that you replaced any of the O rings??

The breather tube is not the issue, but some gasket sealer can fix that up

Using a vacuum sync tool would help theoretically, but in reality you've already compensated for the air leak while syncing your carbs before

[SqDancerLynn1]

Where is the bottom fuel screw set ? # of turns

[drhach]

Yes KZ boots (brand new)
Tes new orings (all of them)Side air screw 1.5 turns.

These are baselines. I did highest idle method from there. So give or take. I started with the fuel screws at .75 turns, it was way too lean.

[trippivot]

when the idle hangs up it is a lean condition.

rich --will go below the set idle speed and recover back to idle set speed.

you are making good sense, maybe re-check that the advancer unit is lubed and snappy.

[drhach]

Well, it works!

The more I thought about this (as if I haven't thought about it enough). I had to conclude that the issue was at the boots bthe carbs and the head and not somewhere else in the system. Here's why, if it was say, a leak in the airbox, I should have been able to compensate for that by adjusting the fuel and air screws. The idle was only hanging when the engine was really warm richening the carbs made the bike worse, not better.

So, given that I have checked and tightened those boots a million times and checked and rechecked as well ultimately replaced them. I had to ask "what's left"? In this case, it was the clamps. I believe that they stretched to the point that they could not adequately tighten on the spigots. So, I went Ace hardware and bought 8 new ones. I got the wider style with the bolt head on them as opposed to ordering the factory ones. I reassembled it all; checked and rechecked everything and fired it up.

I had to make a few small adjsutments once it was up to temp, but it idles good now. In fact, since I have owned it, I really have never been able to get it to idle around 1000 RPM. It sounds really slow. But it holds steady and doesn't waver and it doesen't hang when I give it throttle.

Thanks everyone.

[ddaniels]

I love it when a plan comes together. Good job.

[drhach]

Now I just have to put some time in riding this thing without too much drama. After all I've been through with this thing, I kind of hate it right now. I would have sold it but you can't really get a good price for a bad running bike.

Dan

[BadBillyB]

Dont hate it, Its an antique, and just needs TLC. Now go ride it, and like Big T said, resync the carbs.....Billy

[drhach]

I've given it more TLC than it probably deserved. When I bought it it had been leaning uncovered against the side of some hillbilly's trailer. It was barely worth parting out, but I'm sucker for lost causes. At this point, I think the bike owes me some fun and reliability. Although, I'm not sure it agrees with me