I have a weird thing going on with my 2000 model Magna, on cold starts I sometimes have a cylinder stop firing on me. When it does it, I can hold the revs up to around 5k for a minute or so and the cylinder will kick back in after back firing a few times. After it starts firing again, it purrs like a kitten, can't tell yet which cylinder it is, but it's on the right side of the bike. I'm too tied up for the next week or so to look at it, but I plan on pulling the plugs and seeing what they look like and if they will point me to the right carb, if it's a carb issue.
The bike only has 18K miles on it and is well maintained; I went in and cleaned and shimmed the carbs a couple of years ago and it's ran like a top until this. I doubt it's a coil breaking down, because I'm not losing a cylinder on both sides of the bike, just the right side. If it's not a spark plug, I'm afraid I'll have to go into the carbs and see if I have some trash in a bowl or a sticky float. I also keep pure unleaded, with zero ethanol in it, with stable during the off season, so I doubt it's gummed up jets. Any of you guys ever had one act in this manner?
Quote from: John Luttrell on March 19, 2015, 08:37:49 PM
I have a weird thing going on with my 2000 model Magna, on cold starts I sometimes have a cylinder stop firing on me. When it does it, I can hold the revs up to around 5k for a minute or so and the cylinder will kick back in after back firing a few times. After it starts firing again, it purrs like a kitten, can't tell yet which cylinder it is, but it's on the right side of the bike. I'm too tied up for the next week or so to look at it, but I plan on pulling the plugs and seeing what they look like and if they will point me to the right carb, if it's a carb issue.
The bike only has 18K miles on it and is well maintained; I went in and cleaned and shimmed the carbs a couple of years ago and it's ran like a top until this. I doubt it's a coil breaking down, because I'm not losing a cylinder on both sides of the bike, just the right side. If it's not a spark plug, I'm afraid I'll have to go into the carbs and see if I have some trash in a bowl or a sticky float. I also keep pure unleaded, with zero ethanol in it, with stable during the off season, so I doubt it's gummed up jets. Any of you guys ever had one act in this manner?
Mine have always acted a little like this.. Especially if I choke the bike.. Try different positions of the choke, if you have not..
Mine starts up best with no choke, but Has a little trouble getting off on the 1st pull off with no choke.. So I add just a little choke.. The bike stumbles some (a cylinder or two stops firing) IF I add too much choke..
I doubt it's trash in the carbs, because if it was, it wouldn't clear up and be fine until the next cold start..
BUT a little SeaFoam is NEVER a bad idea!!!
Just don't use THIS kind
(http://i41.tinypic.com/103iijp.jpg)
Yeah, my bike starts better with no choke as well, I should know a little better what I'm looking at after I pull the plugs and look at them. I should probably just change them out anyway, it's been around eight years since they were changed, but that only amounts to maybe eight or nine thousand miles on the set. A lot of those miles are short trips back and forth to work with out the bike really getting to operating temp, so it could just be a plug carboned up.
When the bike is cold, start it up and moving with intent, touch your finger to each of the exhaust headers near the heads. Whichever cylinder is misfiring will not heat its header pipe up as fast as the others. It takes a while for the pipes to get hot so don't worry about getting burned initially. I use this to find gremlins in the Valk's 6 cylinders.
While this could be a fuel issue, don't rule out the ignition system. If its specific to one cylinder it could be anything from the spark igniter, to the plug wire to the plug. Really check out the plug wire once you pinpoint the cylinder that's acting up. This is more easily fixed than a carb teardown.
Quote from: John Luttrell on March 20, 2015, 08:07:19 AM
Yeah, my bike starts better with no choke as well, I should know a little better what I'm looking at after I pull the plugs and look at them. I should probably just change them out anyway, it's been around eight years since they were changed, but that only amounts to maybe eight or nine thousand miles on the set. A lot of those miles are short trips back and forth to work with out the bike really getting to operating temp, so it could just be a plug carboned up.
IF you think it's plugs, just move them around.. If you know your problem is on the right side, move those plugs to the left side.. If he problem follows, then you know it's a plug...
IF not, then work back to the wires, coils etc..
Also when it's missing, you can just start pulling plug wires... When there is no change once the wire is pulled, that is your problem cylinder.
Ok guys, I finally got enough free time to change the spark plugs today and the bike is running great again. It's a cool day out, just the type of day it would have developed a miss on start up and she purred like a kitten on all four. I guess I can't complain, the old plugs were eight years old and through out the winter months, the bike has been ridden on short trips back and forth to work, with out any real chance to warm up to full operating temp.
Thanx for the update..
Did you put in stock plugs or the iridian plugs?
When I decided, after 150,000 miles, to replace the plugs in my '02 Silverado, I took the old plugs out, and concluded that they were severely eroded. I bought Iridium replacements, and, much to my surprise when I took the first one out of the box, it also had a small, sharp point instead of the flat round cylinder I was expecting. Not sure they made much difference in performance or mileage...
Quote from: hootmon on March 27, 2015, 07:34:03 AM
Thanx for the update..
Did you put in stock plugs or the iridian plugs?
I put the stock plugs that the owners manual called for in it.