Cold & Wet...

[Anonymous]

This morning, it was about 40 degrees, and misty. Work isn't real far, and it is supposed to look better this afternoon, so I decided to go ahead and ride. I went through the normal cold start procedure, and the bike seemed to be warming up like normal. I hopped on, and was on my way...

A few blocks down the road, the bike started running rough. It proceeded to get worse as I went along. Adjusting the choke had no impact on how she was doing. A little further along, and I had to keep some decent throttle in her while stopped to keep it from dying.

A little further, and I even had to keep the throttle up while driving. This lead me to downshift approaching a light (to keep rpm's up as I slowed). The engine died, the rear locked up, and I had a good slide going. I was able to figure out what was going on quick enough to squeeze the clutch, recover the slide without a spill, and not end up in the middle of the intersection. More excitement than I like in the morning.

Now, about three blocks from my parking spot (up a steep hill of course), she died, and this time, she wasn't starting back up. Not even a pop. I waited a while, to see if something would settle out, but nothing. So, I started pushing her up the hill. After a block, huffing and puffing, I turned it onto level ground, and got back into the saddle to have a rest. I decided to give it another go, and low and behold, she started right up. I kept the engine racing, and nursed her the last two blocks to where I park.

So, whats going on? ('85 GS550L, w/ the weird double-barrel carbs.)

My best guess is there is some combination of dewpoint / relative humidity / temperature, that is giving me fits. Maybe, as the air is accelerated through the carb, pressure drops, the water vapor becomes liquid, and is really messing with combustion? It has run a little rough in wet conditions in the past, but nowhere near this bad before.

Is there anything I can do about it? (Other than don't ride when it is cold & wet)

Thanks in advance,

Rob

[lhanscom]

My guess, is that the ignition system was having problems with the mist. Hopefully it will startup and run fine when it's not wet. When it happens again, check your spark, remember that cyclinders 1 and 4 share a coil, and 2, and 3 share the other coil, so if you lost a set of cylinders it's probably a bad coil. If you lost cylenders 1 and 2, but not 3 and 4 you may have a couple wires with cracks in them. If they all went, then you'll need to check the voltage at your coils.

[earlfor]

I would suspect the ignition wiring, plug wires and sparkplug boots have aged enough to allow water in and retain it. Try spraying them with corrosion block or WD40 (formulated for displacing water).

Earl

[Anonymous]

More clues

Well, I tried to make it home today. Once again, it started & warmed up ok, and then started running rough. I made it about halfway home. Had to park it & carry the battery home. Hopefully it won't get towed...

The pipe coming out of #1 was only warm. The other three were piping hot.

Thanks for the pointers, I will check into it when I manager to get her home...

Rob

[earlfor]

Re: More clues

Then either the fuel level in the #1 float bowl is too low, the #1 bowl is not getting fuel, or the #1 carb has clogged passages.
Or, the 1 spark plug cap is faulty or not making a good connection on the wire.

Earl

The pipe coming out of #1 was only warm. The other three were piping hot.


Rob

[Anonymous]

Carbs

Earl,

Thanks for the pointers.

Because it has the weird double-barreled carbs, 1&2 share a bowl. But 2 is doing fine. So that points at the clogged passages or the plug cap.

It has done this before when the weather gets wet, so that makes me think it is the plug cap. Sound good to you?

Thanks for all the help,

Rob

[earlfor]

Re: Carbs

If it only does it in wet weather, then I agree, it points to an ignition problem on the #1 plug cap or wire.

Earl

Earl,

Thanks for the pointers.

Because it has the weird double-barreled carbs, 1&2 share a bowl. But 2 is doing fine. So that points at the clogged passages or the plug cap.

It has done this before when the weather gets wet, so that makes me think it is the plug cap. Sound good to you?

Thanks for all the help,

Rob

[Anonymous]

Adverse Weather running

This morning, it was cold, but dry(er). I let it warm up a good long time, and it kept running on all four. I'll go ahead and spray some contact cleaner around, and some terminal grease as a preventative, but if it keeps up, how much does a set of wires cost? $30? Not worth the dangerous running it has been causing...

On a related note, riding in town, in cold weather (35 deg), is pretty challenging. I have to be constantly jockeying the choke up and down. It'll warm up while parked such that I'm nearly off the choke, but ride down the block, and it cools down so much, I've got to pull the choke back in. Sit at the light for a few moments, and the engine is racing. Out on the choke, down the block, and as you come to a slow, the engine wants to die unless you go back in on the choke. A real pain...

Is there something wrong, or is this just the way it is going to be? I have a friend (with an old BMW) who says I should never ride with the choke on. It should take a few minutes to warm up, out with the choke, and I _should not_ put it back in.... Of course, she doesn't ride below about 60 degrees...

Thanks again,

Rob

[lhanscom]

It sounds to me like you probably have another problem beyond your wires. My guess is that you have your idle jets clogged up some, causing a lean condition at low rpm. The cold will make this problem worse then it would be in warm weather. Oh, and no, you shouldn't have to play with the choke once the motor is warmed up, the cold temps will not cool the cylinders enough to cause that.

[earlfor]

Re: Adverse Weather running

Once warmed up, you should not have to go back on choke. I think you have a combination or small problems that together are confusing the situation. If you have minute cracks in the rubber of your ignition wires, invisible water intrusion will ground out the spark. Coat the wire with WD 40 because it is a water displacement formula. Contact cleaner or other type solvents will not do the job. Take a multimeter and check the resistance between the #1 and $4 plug caps and then check between the #2 and #3 plug caps. Resistance on the two pairs should be aproximately the same. Resistance should be between 30k and 50k ohms. If it is greater than than, then you have a faulty plug cap. If it is less than that, you probably have a faulty wire to plug cap connection.

You have the #1 pipe that only gets warm and the engine dies out easily.
This indicates the idle passageway on the #1 side of the left carb is blocked and at idle, the #1 cylinder is running on the choke tube. The engine dies easily because it is only running on three cylinders at idle without choke. I would remove the carb, disassemble it, soak it in Berrymans solution and reassemble with new "O" rings. I would also do a carb synch after reassembly. I suspect part of your rough running problem is the carbs are also out of synch.

The way your bike acts in cold, wet weather is not normal and no, you do not have to live with it.

Earl

On a related note, riding in town, in cold weather (35 deg), is pretty challenging. I have to be constantly jockeying the choke up and down. It'll warm up while parked such that I'm nearly off the choke, but ride down the block, and it cools down so much, I've got to pull the choke back in. Sit at the light for a few moments, and the engine is racing. Out on the choke, down the block, and as you come to a slow, the engine wants to die unless you go back in on the choke. A real pain...

Is there something wrong, or is this just the way it is going to be? I have a friend (with an old BMW) who says I should never ride with the choke on. It should take a few minutes to warm up, out with the choke, and I _should not_ put it back in.... Of course, she doesn't ride below about 60 degrees...

Thanks again,

Rob

[IanFrancisco]

cold and wet

Just my $0.02 - Everyone's right on talking about ignition wiring, WD40, and carbs. I read on a old /2, /5 BMW forum that people had trouble with the carbs ICING UP in high altitude or cold weather. Of course the carbs hang out in the breeze on those bikes but there's my $0.02...

[Anonymous]

carbs & weather

Earl,

Thanks for the clarification on the WD40 & the plug wires. Without you explicitly stating it, it would have never occured to me to spray it on the outside of the wires. I was only thinking of cleaning and protecting the contacts.

Does anyone have a number for the carbs on this bike? They don't seem to have any markings beyond the brand.

http://67.15.65.225/spst/1985%20GS550L/06.htm

I would like to order a gasket/o-ring kit for the rebuild, but I don't really know where to start without knowing exactly what the carb is.

Or would you reccomend I just cut new gaskets and find o-rings that will work at the hardware store?

Rob

[alan]

Here might be nice set of spare carbs.....

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=4531101293&category=0&sspagename=WDVW

[earlfor]

Re: carbs & weather

In looking at the carb diagram you posted, I see that it lists the Suzuki part numbers. Since you have part numbers, you will not need to give a carb model number. The only parts you should need are the "O" rings and possibly float bowl gaskets. I probably would go through the local dealer to order them as cost should be minimal. If not that and if your float bowl gaskets are in good shape/not leaking, you can take a chance and order an "O" ring kit from robert barr at cycleorings.com The kits are for the four carb, single barrel Mikuni CV, but as I have said before, from a logical viewpoint and knowing Suzuki's affinity for standardizing parts, I doubt they would have made the two barrel carbs such that they required different diameter needles and "O" rings than any other of their CV carbs.
The Robert Barr kit should give you what you need, but I cannot be certain.

Earl

Earl,

Thanks for the clarification on the WD40 & the plug wires. Without you explicitly stating it, it would have never occured to me to spray it on the outside of the wires. I was only thinking of cleaning and protecting the contacts.

Does anyone have a number for the carbs on this bike? They don't seem to have any markings beyond the brand.

http://67.15.65.225/spst/1985%20GS550L/06.htm

I would like to order a gasket/o-ring kit for the rebuild, but I don't really know where to start without knowing exactly what the carb is.

Or would you reccomend I just cut new gaskets and find o-rings that will work at the hardware store?

Rob