Three years and still not running! Help me idle! Please!

[Anonymous]

Hey Guys,

Am I happy to find such a board! Been reading the last few weeks and it has got me excited to try getting the old 450 to run again. But I'm having a problem with the idle.

It's a '80 GS450E and the idle has been wandering for the last three years. I've rebuilt the carbs several times to no avail. In fact, this last week I spent $60 for a set that was pulled from a running bike. Put 'em on and still she takes off. Strange that the new carbs have no air adjustment screws, but it's one less moving part.

Anyways, the carbs should be fine. The engine revs to 5000 rpm and so I have to ease the clutch, which does help the bike return to ~1800, but makes for a dangerous ride. Especially since every time I throw the clutch she revs high. The throttle response is little to none. At idle, a quick rasp on the throttle will leave the idle high, or it will slowly settle back to 2000.

Now one thing I'm not sure about is the two long hoses that are at the bottom of the carbs. I never had these on the old one (fell off?) and I don't know what they go to. What I do know is that if I suck on one to make some vacuum, it brings the idle down, but usually I kill it.

Any help??

[Anonymous]

carb problem

Sounds to me like a vacuum leak or you are sucking air in aroung the boots between the carbs and the engine. That high idle that eventually settles down is a sure sign of a system that is drawing air where it shouldn't.

Start the bike, let it idle and spray some combustible aerosol like starter fluid or carb cleaner around the intake boots between the carbs and head and see if the engine speeds up when you do. If it does you found your leak.

Check your throttle cable where it connects to the carbs and make sure it has just a tiny amount of slack in it so it is not keeping the carbs pulled away from the idle setting screw.

Not sure about the two lines you referred to. You probably have two lines going up to your petcock. The larger one is the fuel line, the smaller one is a vacuum line that opens the petcock when the engine runs. My guess is the two lines you are wondering about are drain hoses for overflow gas.

I have not seen a 450 personally. I am writing this from experience on the 850 and 1100. Anybody feel free to correct me if I goofed anywhere.

[Anonymous]

No expert

I'm no expert, but I'd offer this suggestion. Avoid starter fluid, if as I remember, it is mostly ether. Too explosive! I've read folks on this forum suggest WD-40 for this purpose.

[SqDancerLynn1]

What kind of fuel valve do you have? If it is OEM it should have a vacuun line connected from the carbs to the tank. I would plug the lines that you have one at a time to find out which one has vacuum the other would have to be a vent/overflow for the carbs see if that fixes your problem DON"T use starting spray it is highly flamable. plain old windex will work fine to check for a vacuum leak. The air adjustment screws are located underneath a plug on the intake side of the carb. Check in the forum Garage section for pictures of the carb

[Anonymous]

Re: No expert

I'm no expert, but I'd offer this suggestion. Avoid starter fluid, if as I remember, it is mostly ether. Too explosive! I've read folks on this forum suggest WD-40 for this purpose.

plain old windex will work fine to check for a vacuum leak

Yeah, there's too much danger in starter fluid for me it can also degrade the rubber, but WD-40 may not work either. About 2 years ago, WD-40 went to a new formula that makes it much less flamable than before. Besides, it can also leave "goo" behind after the most flammable chemicals burn off. Windex is probably the better idea.

[Anonymous]

Guys,

First I must say you guys rock on. Thanks for the help and suggestions. I worked on it last night. I was having idle problems from the start and thought that the new carbs showed that the old problem was still there.

I did get new boots for the carbs. The old ones were semi-repaired with RTV. Obviously it wasn't enough 'cause the new ones are working better. I figured this could have something to do with it, but never thought it would be THAT dramatic.

After getting a smooth idle, I found out why I can't hold higher revs for too long. I'm only getting firing on one cylinder! This was not a problem last time I had the old carbs on since both pipes were warm. It's not spark so I'll be pulling the carbs again tonight to check for starvation by first draining the bowl (if it has anything to drain!). I'm not sure it will since the exhaust on that side has a colder pipe and the emitted fumes aren't smelling like fuel. I guess I'll see.

Oh yeah, I've been using carb cleaner to check for leaks. I should have tried that on the old boots. Dang, I might have had it going last year had I tried that! Thanks again! I'm off to get some plugs and more carb cleaner!

[Anonymous]

ok ok

I stand corrected on the starter fluid. Guess I live a little more dangerous than I should. Never heard of the windex thing. Alcohol in it or what makes it flammable?

Anyhew, check for spark on the second cylinder before you pull the carbs again. It could be an electrical problem.

[Anonymous]

what about the wd40--doesnt it also make the rubber swell a bit???

[Anonymous]

It's the ammonia in the Windex that makes it work... Kinda like a NO2 burst but the opposite way. In a normal NO2 setup, the extra oxygen allows you to burn more fuel by increasing the percentage of oxygen in the air. By adding ammonia (NH4), you actually add more combustable hydrogens.

WD-40 or carb cleaner will also add more combustable hydrogens, but WD-40 contains "heavier" compounds and the combustion won't be as clean. Carb cleaners contain easily combustable hydrogens and alcohols as well (for added oxygen and cleaner combustion). The only problem with carb cleaners is that alcohols have low flash points and there isn't much to keep it from burning before it reaches the cylinder; or even lighting right out of the can if conditions are right.

[Anonymous]

Hey, far be it from me to offer much in the way of suggestions after all I just went though trying to get mine to run right, but I did learn a lot...

I think most of my problem initially started out a couple years ago when I first attempted to get my bike to run after many years (all told about 7 years). It seemed like a vacuum leak to me at the time so I replaced the boots -- to no avail. The carbs were cleaned slightly, but not rebuilt, to get rid of the green gas. It would start but run really bad.

When I finally tried again this year to get this bike to go again I discovered that little vacuum hose running to the petcock. I bet if I'd have hooked it up two years ago, it would have run fine then. It had rotted away in the 2 or 3 years prior while it sat (while I was married -- another story) and I didn't notice it when I removed the carbs. So check for that hose if your bike has one.

The two lines you refer to are likely the overflow hoses that should be routed to an area that will not spill the fuel on the hot engine or exhaust if the float needle/seat fails. Sucking on them would likely create a vacuum within the float bowl so that it starves that cylinder for fuel. You need atmospheric pressure inside the float bowl -- not a vacuum.

You can also use plain old tap water to check for vacuum leaks too. You're not trying to make the engine run better (for long) when checking for vacuum leaks -- just change the "way" it's running in any form. Anything that temporarily blocks to source of air entering where it shouldn't will change the way the engine runs (hopefully for the better), so you don't really need combustibles present. In short, if squirting anything external to the carbs changes the way the engine runs, it's a likely source for the vacuum leak.

Cheers,

Roger Moore

[Anonymous]

I got that vacuum tube and it is hooked up. Yup, you guys are right on the overflow tubes. Just thought with their length that they might be hooked up to something. Made me very curious. The tube ends disappear in the drawing in the service manual.

The spark is there, but not great. I'm changing the plugs for the old ones are pretty foul. After pulling the plug, I found it was dry. I'm going to try the old cover-the-intake-and crack-the-throttle trick to see if I can dislodge whatever is in there. Otherwise it's a carb teardown night!

On the combustion thing, you can get flour to ignite with the right air/fuel (flour) mixture. I do some fire-breathing (hence, one reason for the user name) and some guys in the profession have a technique where they pack different materials into cylinders and puff them out in a quick huff by a torch to get the flame.

Roger, I'm wondering if you are the GSTwin Digest guy known as Michael Moore on that other site. Just thought in my search that it was coincidental that the Michael Moore movie "Roger and Me" is directed at Ford exec with the title Roger Moore. Figured you might be a hardcore fan using aliases on the topic.

[Anonymous]

Roger, nice Ford, by the way! '54 right?

[Anonymous]

Nope, just a plain old Roger Moore -- no fancy cars or women The truck is my 56 F-100 panel. Have had it for 20 years. It's been through many a change in 20 years, but I did a frame off/frame swap using a 79 LTD station wagon a few years ago. This required me to re-design everything to work, from mechanical to electrical. It's pretty cool -- a real head turner (snapper off-er). Paint, I did, but it really deserves a $10K paint job, but I don't have 10K to spend on it. Have a rust-free 1965 2 door Falcon station wagon that has my interests right now. It's as odd to see as the panel, but the panel is really fun.

OK, I know, this is supposed to be GS talk.... I'm sorry :roll:

Later,

Roger Moore (not the Saint, not James Bond, not Michael Moore -- just me)

[Anonymous]

When I decided to revive my 88 450 after sitting for 3 years I had very similar problems to yours. I ended up rebuilding the fuel selector valve for around $25.00 (purchased from the local shop), cleaning the carbs which were in need of it, especially the air adjustment screws and the choke valves. On my carbs the idle screws are on the top of the carb located in front of the intake boots. To clean them, to were they would perform properly, I had to let them soak for three days in carb cleaner.

Before I did all this work, the fuel selector valve diaphram was bad which in turn caused the vacuum to suck gas and send smoke out of my right exhaust, I tried simply pinching off the vacuum, but then the correct amount of fuel was not being supplied and it backfired terribly.

Hope that some of this helps, good luck

Nathan

[Anonymous]

I just realize I said no fancy cars or women... but many would consider both of my cars "fancy." Apathy on my part, I guess. But hey, even this GS750EX is fancy -- Hey, I guess all I really do need is the women