Exhaust and smoke? Help!

[Anonymous]

I tore down and rebuilt the carbs in December on my bike (1980 GS550L), but couldn't get it running before I left to study abroad. Also started working on the exhaust. Now that I'm back, I put the new exhaust on and today was trying to get the whole thing running.

When I started it up, it sounded just fine. But I pretty quickly noticed some slight whisps of smoke coming from the front of the bike near the exhaust/head connection. I quickly shut the bike off, so I only had it running for maybe 15 seconds. Any thoughts on what the smoke might be from (new gaskets, anti-seize, etc.)? I'm a little afraid to turn it on again in case that's a problem.

Since the bike's been sitting for three months (no fuel in carbs), could it be linked to that? I had to recharge the battery slightly. Also, after I turned the bike off, I felt the pipes. #1 and #2 were room temp, while #3 and #4 were slightly warm, almost like the cylinders on the #1/#2 side weren't firing. Any thoughts?? Could it be linked to the smoke? Thanks a ton.

Gotta get this thing back on the road!!

--Tyler

[Motorcyclemodeller]

Sounds like exhaust leaks, when you put on a new exhaust system or after several exhaust pipe removals, you should put new exhaust gaskets in. You should use an anti-sieze compound on the bolts, or even better install studs and use nuts.

As for #1234,

#1 and #4 fire at the same time
#2 and #3 fire at the same time

If you removed your coil wires double check, on my bike the coil on the clutch lever side fires 1 and 4.
And the coil on the brake lever side fires 2 and 3.

The exhaust leaks will not cause any damage, but get her running on all 4 cylinders first.

Sometimes it takes a few minutes for all 4 cylinders to light up after a storage period, it could be oil sepage on the pipes or flanges.

Dr. Dre

[Anonymous]

Re: Exhaust and smoke? Help!

I tore down and rebuilt the carbs in December on my bike (1980 GS550L), but couldn't get it running before I left to study abroad. Also started working on the exhaust. Now that I'm back, I put the new exhaust on and today was trying to get the whole thing running.

When I started it up, it sounded just fine. But I pretty quickly noticed some slight whisps of smoke coming from the front of the bike near the exhaust/head connection. I quickly shut the bike off, so I only had it running for maybe 15 seconds. Any thoughts on what the smoke might be from (new gaskets, anti-seize, etc.)? I'm a little afraid to turn it on again in case that's a problem.

Since the bike's been sitting for three months (no fuel in carbs), could it be linked to that? I had to recharge the battery slightly. Also, after I turned the bike off, I felt the pipes. #1 and #2 were room temp, while #3 and #4 were slightly warm, almost like the cylinders on the #1/#2 side weren't firing. Any thoughts?? Could it be linked to the smoke? Thanks a ton.

Gotta get this thing back on the road!!

--Tyler

Could just be burning off whatever is on the headers. As far as 2 pipes warm and 2 cold. Check that your plug wires are on the correct plugs.
I made that mistake once.
Let us know what you find.
BTW good to see another MD GS.
I am located in Columbia MD. Where are you?

Charlie

[Anonymous]

Ok, I played with it some more. Checked the spark plugs, and for some reason, the first one wasn't sparking (no matter where connected, even if the others sparked at the same connection). Didn't know plugs went bad. Replaced that though, but #1 and #2 still won't fire. I've had it running a bit more, to a point where I would think that the cylinders would free up if they were stuck at all after 3 months. Could it need more running to free them up? Their exhaust pipes stay cold while the others get quite warm.

Another interesting note: I also have the Carbtune 2 attached to the bike at the moment because I was going to be synching the carbs before these problems came. However, I've noticed that when the bike is running, the carbtune shows no readings at all...almost like none of the cylinders had a vacuum. No kinks in the tubes or anything that I can see that would cause that. Weird.

--Tyler

Charlie - I'm in Rockville

[Motorcyclemodeller]

Which coil and which wires go to which plugs?

I think it's back to basics here:

Remove plugs, reconnect to lead; ground to block; crank motor and check for spark.

No spark to 1 or all, faulty plugs, wires, coils, pickup coil, ignitor box: test all

Spark at all 4

No fuel flow to clylinders 1 & 2, Something wrong in carbs, open drain screws to make sure bowls are full of fuel, there may be an airlock somewhere.

Air, Fuel, spark; check for all three; they must all be present and at the right time for ignition to take place.

Let us know,


Dr Dre

[Anonymous]

Unless you have 2 bad plugs, cylinders 1&2 have no correlation to each other. Cyl 1&4 fire from one coil and cyl 2&3 fire on the other. My guess is that the carbs may be still a little dirty. As far as the carbtune not showing any vacuum, you have to be holding at least partial throttle open to keep it running right? That's why you show no vacuum. Air box and filter on correctly with no leaks?

[Anonymous]

I think I had one bad plug, which I've replaced (the #1). I now get sparks from all four, but #1 and #2 still don't fire.

As I said, I carefully cleaned out the carbs since the last time the bike's had gas in it. And all four cylinders fired before I started tearing it apart (in December). I'll check the drain bowls and let you know if those are bad. If there's an airlock in there, what's the best way to get rid of that?

I have one coil going to the 1st and 4th plugs, and the other coil going to the 2nd and 3rd, so I don't think a coil has gone bad.

When I had the bad #1 plug, it was wet, suggesting that gas was at least getting to it. Unless it was still wet from back in December, although I think the #1 was working at that point.

Since I took the carbs off to clean them, it's possible that there's a leak between the connections of the airbox and carbs. I put silicone on the rubber when I put it back together though. What's the best way to check for leaks?

As for the lack of vacuum, that makes sense. I didn't let the bike warm up, so I was running it with the choke.

Thanks for the help!

--Tyler

[Anonymous]

First drain bowl has fuel, so I'm guessing the second does as well, as it has to flow through the second to get to the first. Any other thoughts?

--Tyler

[Anonymous]

Take the plugs out of #3 and 4 and see if #1 and 2 are just running cold instead of not running at all. Or switch the caps from #4 and #1 and #3 and #2 to check the wires. If #3 and #4 are running then you know you have good coils(you've only got two right?) and I'm guessing your igniter would have to be good as well. It's likely a carb issue if not the wires.

[Anonymous]

I think I had one bad plug, which I've replaced (the #1). I now get sparks from all four, but #1 and #2 still don't fire.

Thanks for the help!

--Tyler

OK you got spark at all 4, but one and one and 2 dont fire. When the shop put Dyna coils on my bike the inaverentl switched the plug wires around, They all had spark and the coils were brand new just 2 plug wires stripped so bike wasw running on 2 cyl hot 2 stone cold. Humor me and try making sure correct coils are connecetd to the right plugs

WHen you get it goin lets take a ride. I can come to your place and help you get it straightened. That way we would have my bike there to compare, Just say when and Ill be there.
Charlie

[Anonymous]

First drain bowl has fuel, so I'm guessing the second does as well, as it has to flow through the second to get to the first. Any other thoughts?

--Tyler

Not true. Fuel flows through the fuel tubes but that doesn't mean that it has to be getting by the float valve in carb #2 and into the bowl. Is spark plug #2 wet? If it is, maybe your petcock diaphragm is bad and flooding #2 before it gets a chance to fire.

[Anonymous]

Yeah, the right wires from the coils go to the correct plugs.

Spark plug #2 was dry, sort of suggesting that the fuel wasn't even getting to the plugs.

Since the #1 plug was bad, I'm going to replace all the plugs today to make sure that wasn't the problem. I'll also check the #2 float bowl. But since the #1 also wasn't firing (even when it was getting spark) and its bowl had fuel, it would seem that perhaps the problem is elsewhere. Any other suggestions??

--Tyler

[Anonymous]

Tyler,
Detman101 is in Silver Spring or Bethesda, Landscapeman is in Columbia, I'm in Annapolis, and Nick Diaz is in Frederick. We should be able tio converge on your house and smack your bike into submission if you want. We all have our troubleshooting techniques and systems so we should be able to discover the problem.

Harrison

[first timer]

take the spark plug boot off the plug and look into it, you will see a flat head grove for a screw, unscrew it and that hold some resistors in there, clean up that stuff, sand the ends of the resistors a little so there is no corosion there. and sand the brass peices shiny and and clean the ends of the spring and take a small flat screw driver and stick it up into the boot with everything gone and turn it around a little so you clean that connection up there too. that stuff gets pretty nasty and can limit the spark to the plug.

-ryan

[Anonymous]

I managed to get all the cylinders firing! After putting the new spark plugs in and not totally knowing what else could be wrong, I decided to just run the bike. After running it for maybe five minutes on just the #3 and #4 cylinders, the #1 started to cough and finally come to life. After a while, #2 did the same.

However, I don't think #1 and #2 are all that strong, at least when I first start up. I let the bike cool down and then restarted it again. #1 and #2 took some time to start firing again. Is that something that is apt to go away with a little more engine running and some riding?

Ryan - The #1 spark plug cap was only about 6 months old, because it went bad on me. I did take apart the #2 cap though and tried to clean it. I wasn't ready for all the little pieces to fall out in my hand, but I think I got it back together just fine (based on pulling apart the #3 CAREFULLY).

Thanks a ton for the help.

--Tyler