Author Topic: What is this knob for? (Read 9173 times)

rarick123 · « **on:** March 28, 2005, 12:52:57 AM »

On the left hand side of the bike (if you're sitting on it, facing forward), down near the RES/PRI/ON petcock, there is a black knob that seems to be attached via a cable to the carbs. What is this knob for?

I ask because I'm trying to get my 2000 B6 started again after nearly 6 months of not running. It actually fired up today for about 30 seconds, and then when I backed off on the choke, it died and wouldn't fire up again. Only thing I have really messed with since it ran was this knob.

FreediverGa · « **Reply #1 on:** March 28, 2005, 01:18:16 AM »

It's the idle adjust knob. I'll let the other guys explain to you how to use it, I'll just confuse the hell out of you ! just turn it alittle at a time, you really don't need to turn it much for it to do it's job

Red01 · « **Reply #2 on:** March 28, 2005, 05:54:26 AM »

Basic equipment rule #1:
If you don't know what it does, don't futz with it.

I know, too late now...

Try to put it back to where it was. Failling that, keep adjusting it until you can get it to start. Once it's warmed up, adjust it to idle at ~1200 rpm.

aussiebandit · « **Reply #3 on:** March 28, 2005, 06:04:34 AM »

Actually, it's funny yhou should mention the idle adjust. Last week some knob at work thought it would be funny to 'adjust' the idle for me. I thought "f%^k, what's gone wrong now, just what I don't f#$%ing need". When I got home my eldest said "What's wrong with your bike - it won't idle properly". I won't tell you what I said in response, but during my rant I suddenly thought "idle adjust screw - I wonder". And sure enough fixed.

Can anyone think of a feasable way of 'securing' this part of the bike.

Red01 · « **Reply #4 on:** March 28, 2005, 06:32:33 AM »

Quote from: "aussiebandit"

Can anyone think of a feasable way of 'securing' this part of the bike.

The idle adjust knob connects to the idle adjust screw via a rubber hose. Disconnect the hose and you should foil would-be idle tamperers.

aussiebandit · « **Reply #5 on:** March 28, 2005, 07:40:24 AM »

Cool, thanks Paul

rarick123 · « **Reply #6 on:** March 28, 2005, 09:18:40 AM »

OK, given that I broke the cardinal rule and "fixed" something that wasn't broken...

is it safe to assume that taking the adjustment all the way to one end, counting the number of turns all the way to the other end, and then backing it down to roughly the middle is the right place to start? Or should I start with it cranked all the way clockwise, or all the way counter-clockwise?

On a related note... is it possible to turn this screw too far and completely back it out from the carb? I've messed with it so much, I'm afraid it might be hosed up now.

PitterB4 · « **Reply #7 on:** March 28, 2005, 11:14:17 AM »

At least on the B4, the other end of the adjuster is kind of like the end of a screw that pushes on the linkage that opens the carbs. The more you turn it in, the more they open (raising the idle). You CAN back it out so far that it is no longer touching the carbs (and therefor no longer doing anything). On my bike, if you have enough light, you can see where the end of the adjuster is. If I were doing this, I'd get so it just touches and then screw it in another 1 full turn, start it up and see where you are. If it still dies on you, turn it in some more. If it's too high, back it out. It's going to be trial and error getting it right.

Again, this is based on my experience with my B4. Your mileage may vary! The bottom line is that you certainly can back it out too far so your idea of finding the 'middle' won't work. Plus, I would guess that the middle would be WAY too high. Screwing it all the way in would be something like having the throttle wide open.

Airmotive · « **Reply #8 on:** March 28, 2005, 01:43:51 PM »

Since it sounds like you're going to be taking your carbs apart pretty soon (6 months parked, and now only runs under choke), might as well leave the idle adjustment alone until you clean your carbs. Then it's simply a matter of warming up the engine and adjusting it to 1200 RPMs.

Red01 · « **Reply #9 on:** March 28, 2005, 08:01:18 PM »

Try what Rob says first.
If you didn't put fuel stabilizer in your gas or drain the carbs before it's six month storage, you're almost 100% guaranteed the opportunity Airmotive speaks of... which is to tear the carbs apart and clean out the varnish-like substance the old gas has tuned into.

rarick123 · « **Reply #10 on:** March 29, 2005, 12:36:22 AM »

OK, so who has a good step-by-step webpage that can walk me through ripping the carbs out and getting them cleaned up?

Yes, my Clymer manual is on order... I'm just impatient.

Red01 · « **Reply #11 on:** March 29, 2005, 02:24:01 AM »

Don't know if there is one. Besides being patient and waiting for the book, just take one carb apart at a time and use the others as a Chinese Blueprint.
(No offense intended to the Chinese.)