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My '78 XS1100 has got me perplexed. I've only got a couple hours run time on it since it was resurrected after sitting for about 10 years. At first it ran great (most of the time), then it started not firing on #4. The pipe was only warm. I could pull the plug wire off and put a spare plug in it and it was firing. I thought maybe the valves were sticking. Then the next time I took it out, #4 was firing, but #1 wasn't. Now #1 & 4 are firing, but #2 & 3 aren't. However, I can put a spare plug in #2 wire and the spare plug fires great. Any ideas?
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First thing I would try is unscrewing each spark plug cap and cut 1/4 inch of wire off, then screw the caps back on and try it again. Corrosion forms at the ends and can give you a weak or no spark. HTH2H7 (79)
3H3
"If it ain't broke, modify it"
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As eratic as this sounds, I'm with Phil. I think you have one or more corroded connections in your ignition circuit. Also do not overlook that old glass tube fuse box if you still use it.Life is what happens while your planning everything else!
When your work speaks for itself, don't interrupt.
81 XS1100 Special - Humpty Dumpty
80 XS1100 Special - Project Resurrection
Previously owned
93 GSX600F
80 XS1100 Special - Ruby
81 XS1100 Special
81 CB750 C
80 CB750 C
78 XS750Comment
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I am going with the plug wires too. Does the bike still have the original coils? If so try the new wires in old coils fix then it just eliminates the possible problem of 30 year old wires. You can find that fix here http://www.xs11.com/forum/showthread.php?t=137Nathan
KD9ARL
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1978 XS1100E
K&N Filter
#45 pilot Jet, #137.5 Main Jet
OEM Exhaust
ATK Fork Brace
LED Dash lights
Ammeter, Oil Pressure, Oil Temp, and Volt Meters
Green Monster Coils
SS Brake Lines
Vision 550 Auto Tensioner
In any moment of decision the best thing you can do is the right thing, the next best thing is the wrong thing, and the worst thing you can do is nothing.
Theodore RooseveltComment
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I had a similar problem with mine after i replaced
my engine with a spare that had been sitting for a few
years, mine was doing it on cylinders 1 or 4, if the engine
is burning oil be careful not to have the carbs running rich
it will cause the plugs to foul.
there was a few times i had to ride it home holding the spark lead just of
the spark plug to get the cylinder to fire.pete
new owner of
08 gen2 hayabusa
former owner
1981 xs1100 RH (aus) (5N5)
zrx carbs
18mm float height
145 main jets
38 pilots
slide needle shimmed .5mm washer
fitted with v/stax and uni pod filters
[url]http://www.youtube.com/watch?v=3pA8dwxmAVA&feature=mfu_in_order&list=UL[/url]Comment
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Have you pulled the plugs? They could be dead or carboned up. I had my bike running way too rich... when I put in fresh plugs, it would run great for about a half hour, then it would idle really crappy. I'd pull the plugs, clean them, and it would run fine for another half hour.
The reason I was having this trouble was because I had replaced my idle mixture screws, and I put them in way too rich. Each time I pulled the plugs to clean/inspect them, I tightened the mixture screws. I eventually got help from another member with a Colortune, and got them adjusted much better.
Good luck!'80 SG with motor from a '82 XJComment
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