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**Anonymous** · 11-20-2003, 08:05 AM

Time to take your mechanics advice.

Time to take you mechanice advice. If you can pull the plugs on the bike you probably won't have to re-synch them. Just back the ones that are lean out till your plugs all get a chocklate tint to the white part. It wouldn't hurt to make sure they are balanced afterwards.

Not sure how you cleaned the carbs in the first place without removing them. If you got cleaning solution in that passage you may need to replace the O-rings that are at the base of the air/mix screws. Wait a min. Does all this apply to VM carbs? I think someone with a 79 or older needs to chime in. It should be though.

**AOD** · 11-20-2003, 06:01 PM

hard warm starts can sometimes be the coils...as things get hotter the resistance increases. if you have the original coils on the bike, i suggest swapping out to some Dyna or Accel coils....they made a world of difference on my bike...which is the same as yours.

the screws on the bottom, yes they need to be removed, and the orings replaced. first however, you need to carefully tighten the screws down...counting how many turns they are in. write this number down...it should be somewhere between .75 and 2 turns usually. BE CAREFUL NOT TO SCREW THEM TOO TIGHT OR THEY"LL BREAK OFF IN THE CARB BODY. sorry for yelling, but it happened to me, i dont want you to have the same pain.

after you count turns in, remove the screws, and use a carb cleaner spray in the holes. replace the oring on the screw if possible...you may need to order carb kits for that...because Suzuki dealers wont give you that o-ring. if you can reuse your oring...you can do that too...

hope this helps,

~Adam

**Anonymous** · 11-21-2003, 07:09 AM

79 GS550E carbs

OK, I guess I didn't make myself clear enough. All the circuits (yes they are VMSS carbs)have been cleaned out except the SEALED ones (fuel mixture - not air) at the back of the underside of the carbs that everyone says not to touch. The o-rings have all been replaced, jets cleaned, choke circuits flushed and backflushed, and even replaced one badly grooved needle and seat. I also replaced the o-rings between the manifolds and head because I found vacuum leaks caused by cracks in them as well as a leak in the vacuum line going to the fuel petcock. The carbs almost look new. I wanted to be very thorough since I got some VERY (bottom of the tank type)bad gas and needed to flush them out as completely as I could.
If you are using a Haynes manual #363 for GS550 & 750 Fours the painted screws I'm refering to are in paragraph #9 on page 72 and are shown in the illustration #5.6a in the upper center. There is a hole in the float bowl that they are exposed through. They are called fuel metering screws. In the Clymer manual # M373 page 189 they are called "small jets" in the 'caution' paragraph and shown in figure 37 with the float bowl removed. Both manuals suggest a 2 turn-out initial setting for the AIR screws after a complete rebuild. That's currently where they are set. I have a friend with a flow bench who can fine tune those for me (he did my Super Hawk carbs), but the hard start problem was there before the bad gas ever entered the equation. That's why the tech suggested cleaning and adjusting the metering screw/small jets. But the warnings in both manuals make me nervous about doing so. Are we talking about the same screws?
I will investigate your suggestion about the coils. They do seem to be original. Is there a simple test to see if they are functioning correctly? My time is abundant-my money isn't!
Thanks for the help guys! If, as they say, a little bit of knowledge is a dangerous thing; I must be explosive!

**Anonymous** · 11-21-2003, 07:56 AM

Ignore those people.

Who ever told you not to touch them should be ignored. I forgot to tell you to count the turns first. You need to pull those plugs and clean that passage. The screws have a needle on the end. Also they have a spring, washer, and tiny O-ring.

Pull the plugs.
Gently turn the screws all the way down counting the turns till they bottom out.
Back them out and remove them.
Make sure the passage is clean.
Replace the tiny O-ring. (Probably left over from the kits you used)
Put the screws back in, bottom them out, and back them back into the original settings.

Now if you have any cylinders that are running lean you can adjust them by backing the screws out further.

The only people who don't want those screws removed are those who don't care how lean your bike is running. Even if its detrimental to your engine.

**earlfor** · 11-21-2003, 11:30 PM

It sounds to me like your fuel pilot jets are varnished up. That you have three cylinders that do not warm up indicates it is the fuel pilots or the choke passageways that are the problem. The reason they dont warm up is there is not sufficient fuel for combusion. :-) :-) Those are the ones the protrude at the front of the float bowl underneath the carb. My 750 has the same sype of VM carbs as your bike and in my rebuild of the carbs, I found the fuel pilots were factory set at aprox 3/4 turn out (the yellow sealing paint was unbroken) I reset my fuel pilots to 1 1/4 turn out about 30,000 miles ago and they have been fine. I have my pilot airscrew (screw on top left side of carb) set to 1 3/4th turns out. My 750 has sat as long as 3 weeks without being touched and all I need is to pull 1/2 choke, turn the petcock to prime for about 10 seconds, reset petcock to run and touch the starter button. The bike is running in less than two seconds and in 15 seconds, I can push the choke to off. I am assuming you are not touching the throttle when you try to start the bike. Twisting the throttle cancels the function of the choke, so you cannot use throttle to start.

You can check your coils with a multimeter. The resistance between the two terminals on the coil (+ and -) should be between 2 and 5 ohms. An average reading will be about 3 ohms, but anything between 2 and 5 is considered OK. Resistance between the spark plug caps should be between 30 and 40K ohms. (if there is a problem here, it frequently can be solved by removing the caps from the wires, snipping off the end of the wire to show clean, new core wire and buying replacement NGK plug caps. Replacement NGK caps should cost about $4 each.
(My 79 750 is running on the original coils and they are fine :-) )

Low fuel level in your float bowl will also cause difficulty in starting.
My float levels in the 750 are set to 25mm, but I am not sure the setting would be the same for a 550.

A faulty petcock diaphram will also cause hard starting, but if it is the petcock, then starting with it set to prime will bypass a faulty diaphram.

Unsynchronized carbs with too low of a vacuum level will also make starting difficult. My carbs are set to draw 25 inches of mercury at 2000 rpm. I would expect intake vacuum on our bikes to be the same since it is not dependent on displacement.

On timing....... for start up, dynamic timing for advance would not be a factor. I'm assuming you are static timed on the |F1 and |F2 and the mark is aligned center with the 12 oclock breaker plate mounting screw. (if your bike does not have a case timing mark....mine does not)

Earl

**KEITH KRAUSE** · 11-22-2003, 03:52 AM

I agree. You are not getting enough fuel. The colder it is, the more lean it gets. I assume the choke plungers are working smoothly and the choke circuit is clean. I would not change the settings of the pilot screws. If they have never been disturbed, the problem is not related to their settings.
The o-rings should be replaced and the pilot circuits cleaned and blown out with compressed air. I believe your carbs have 2 very small holes that lead into the carb throat. One hole comes from the pilot jet and the other hole is regulated by the pilot screw. Look down into the carb from the top and you should see them. These need to be perfectly clear.
The pilot jet also needs to be clear. Are you sure they are the correct size?
The side air screws should be about 2 turns out.
The float height needs to be checked. Check the coils/leads/plug caps for good connections and check the sparkplug gaps.

**Anonymous** · 11-26-2003, 03:42 AM

Thanks for the info guys! Now my only problem is being able to put tools down once I pick them up (temp = below 32 degrees...like a tongue on a flagpole)! Wife won't allow bikes in house and shed's not heated or big enough.

**KEITH KRAUSE** · 11-26-2003, 11:04 AM

The wife won't allow bikes in the house!? 8O But it's Thanksgiving!
This sounds like a job for (music please).....GS Man!!!

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Carburetors 79 GS550e 30k miles

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