How to reset the "DO NOT TOUCH" mixture screws

[shinglejohn]

I have a 78 550 with VM22ss Carbs. Removed them to clean and removed the fuel mixture screws. The manual is so helpful in this area with the assertion "Do not touch!!!!(or else!)".

Im sure im not the first guy to do this, and something tells me the bike is not ready for the junkyard now.Anyone have an idea to how many turns out to start with?

Thanks!

[JEEPRUSTY]

http://www.thegsresources.com/_forum/showthread.php?t=173098&highlight=VM22ss

You will be inundated with a welcome by BassCliff soon.
Welcome from me.

[chuck hahn]

When you take out then plug scratch a mark inline with the slot..then turn each one in till it seats and write down the totals for each carb. once youve cleaned and rebuilt them reset each carb to the corresponding settings.

[Nessism]

Fuel screws should be roughly 3/4 - 1 turn from lightly seated. Check to make sure the tips are not broken off in the carb body. Air screws should be about 1.5 open as a start point. Of course this assumes you have the stock airbox and exhaust installed and properly sealed.

[Steve]

Yep, the stock setting was about 1/2 to 5/8 turn out, but was dreadfully lean. With a stock bike (airbox and exhaust), about 3/4 or a little more will work for the fuel screw (the one on the bottom). As a rule, the air screw (the one on the side) will start about double the setting of the fuel screw, but should be tweaked from there for the best idle. If you have access to a ColorTune (a clear spark plug), you can actually tune it for the best mixture, based on the color of the flame.

.

[chuck hahn]

Steve..thism ism the first ive heard of this CLEAR spark plug..please expound!! So just what does the correct flame in the cylinder look like?

[JEEPRUSTY]

Steve..thism ism the first ive heard of this CLEAR spark plug..please expound!! So just what does the correct flame in the cylinder look like?

Colourtune uses a clear collar in the plug.
Look it up on youtube.

[chuck hahn]

Very cool..so am i correct to assume that as you adjust the air screws youll see a change in the color of the flame? Whats the optimium that one would be looking for using this devise??

[hampshirehog]

Very cool..so am i correct to assume that as you adjust the air screws youll see a change in the color of the flame? Whats the optimium that one would be looking for using this devise??

You should be able to get a nice violet or electric blue flame, set just before it goes yellow. Works a treat.

[JEEPRUSTY]

Very cool..so am i correct to assume that as you adjust the air screws youll see a change in the color of the flame? Whats the optimium that one would be looking for using this devise??

I think tis a blue flame then turn the screws to richen a bit.
Again you can see a vid on youtube.

http://www.youtube.com/watch?v=QKH6undDviI&feature=related

is one.
Many of the vids have the yellow and not the blue. Odd considering they are trying to showcase the tools efficacy.

[chuck hahn]

Yes..and I just saw the other thread as well..sounds intriguing.

[shinglejohn]

Great. Thanks for all the help!

[BassCliff]

Greetings and Salutations!!

Hi Mr. singlejohn,

You'll find more information on those wonderful tools, the Colortune and the Carbtune at http://www.carbtune.com. (Hmmmm, their site seems to be down at the moment.) For less than half the price of what a shop would charge to sync and tune your carbs once, you can get the tools to do it yourself as many and any time you want.

Anyway, let me dump a TON if information on you and share some GS lovin'.

I just stopped by to welcome you to the forum in my own, special way.

If there's anything you'd like to know about the Suzuki GS model bikes, and most others actually, you've come to the right place. There's a lot of knowledge and experience here in the community. Come on in and let me say "HOoooowwwDY!"....

Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", "Top 15 Tips For GS Happiness", the Carb Cleanup Series, and the Stator Papers. All of these tasks must be addressed in order to have a safe, reliable machine. Now let me roll out the welcome mat for you...



Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

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BassCliff

[Steve]

Very cool..so am i correct to assume that as you adjust the air screws youll see a change in the color of the flame? Whats the optimium that one would be looking for using this devise??

My experience with a Colortune is rather mixed.

Last year, I used one with TheCafeKid to help tune up Simon's bike before they got here from Australia. It worked VERY WELL. I took it home to use on my bikes, but could not get the same results. Note that Simon's bike is a '76, with VM carbs. The adjustment to the pilot mixture is made by setting the pilot fuel screws to a somewhat arbitrary setting (about 3/4 turn), then adjusting the air screw for the proper mixture. All of my bikes have CV-type carbs, where the pilot mixture is pre-set with fixed jets in the carbs. You only control how much of that mixture is admitted to the carbs. I saw a decent color when I started, but the color never changed when adjusting the mixture screw. As I turned the screw in, the flame started to go intermittant, and finally quit. You could hear the bike now running on three cylinders. As the screw was turned back out, the flame started flickering in (same color as before), then finally appearing steadily. My conclusion is that if you have VM carbs, it could be a useful tool. If you have CV-type carbs, get if you just like to have a bunch of neat tools, but don't expect to have it dial in your mixture.

.

[BassCliff]

Hi,

I have a Colortune but I've never used it. I always use the "highest idle" method.



Thank you for your indulgence,

BassCliff