Idle Problem

[Guest]

Hey guys,
I'm new to this forum and road bikes. I used to ride motocross a bunch and decided it was time to buy a project bike. I just got a '78 GS1000, it wasn't running at the time and I can get it to start up but it is idling in the 7-8k range so I kill it within a few seconds. The PO obviously didn't know what he was doing because all the fuel and vacuum lines were in the wrong place and I'm surprised it ever ran.

I cleaned the carbs already and am just wondering what could cause it to idle that high. I've turned the idle screw very low and am having troubles fixing this. Also I'm new to working on bikes but tend to pick it up pretty easy. Any feedback on what is causing this would be great thanks.

[Steve]

First of all, WELCOME.

Second, how did you "clean the carbs"?

Third, 7-8k is NOT "idling".

Let's assume for a moment that you did a proper cleaning of the carbs. If the throttle cable is installed incorrectly, it will hold the throttle open, regarless of the idle screw setting.

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[Andrew Vanis]

Let's assume for a moment that you did a proper cleaning of the carbs. If the throttle cable is installed incorrectly, it will hold the throttle open, regarless of the idle screw setting.

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if the throttle cable is installed correctly (with a bit of slack in the cable) he might not have bench synched and the idle screw ended up high or he bench synced with a 1/4" bolt rather than a paperclip

[Steve]

if the throttle cable is installed correctly (with a bit of slack in the cable) he might not have bench synched and the idle screw ended up high or he bench synced with a 1/4" bolt rather than a paperclip

Could be, except that he said he backed the idle screw out all the way, which would eliminate that problem.

By the way, I don't use a 1/4" bolt or a paper clip (which is made of metal ) when I bench sync carbs. I use a light table and look at the sliver of light under the throttle.

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[nathanmaus]

I didn't take the gang plate off and left all 4 carbs connected because I didn't want to sync the carbs (I heard this can be a pain) and was told I could clean everything without taking them apart. (is this true?) I soaked all the jets in carb cleaner, cleaned the bowls, and basically any hole or crevasse I saw with carb cleaner. I could be missing something because I did this 2 weeks ago.
I'll double check the throttle cable but it seemed fine when I reconnected it to the carbs. These do have pod filters on them and I don't know if the carbs were rejetted or not since this was all done previously to me owning it.

[Steve]

I didn't take the gang plate off and left all 4 carbs connected ...

Go back to Square One, do the job right. You simply can not get all the passages cleaned and replace all the o-rings if you don't separate the carbs.

Also, if you are aware that jetting needs to be changed due to your pod filters, but did not verify it when the carbs were open, there is no sympathy here.

Doing a carb sync is not much of a problem, as long as you have (or have access to) the proper tool. Don't worry about the price of the tool, it's NOT a one-time use thing. You will need to check your valve clearances every 3=4000 miles. You will need to check your carb sync at the same time, especially if you changed any shims.

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[nathanmaus]

Thanks Steve I will get on that as soon as possible. I didn't know that pods required rejetting until a few days ago, plus I am new to this and wouldn't know 1 jet from the other. What's an easy way to determine this? Do I just need to measure the ID of the jet and cross reference that to my manual?

[winfield]

nathanmaus,

I don't think you introduced yourself in the GS Owners forum. If you had done that one of the members, BassCliff would have welcomed you with a link to his information page made especially for new owners of a GS. It is chock-full of essential information for newbies. I will include a link so that you can reference it. Read it and re-read it and you should be able to sort out a lot of the problems. There is a tutorial for carb cleaning there that will probably solve most of the problem you described in the first post.

Here's the link: http://members.dslextreme.com/users/..._Greeting.html

[saucebox]

As far as ID'ing the jets—they're usually stamped with the number on the body of the jet itself.

Like these (hard to see the number, but these are all stamped)—



Steve will steer you right on the rest. (Do follow his signature to get the valve adjustment sheet—makes it tons easier to keep track of...)

[nathanmaus]

So I did a full clean and followed that carb tutorial from the BikeCliff site to the T. I haven't vacuum synced them yet because I still can't get the bike to idle properly. They were bench synced though. Anymore ideas on what might be causing this?