Plug pics
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htown16
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Ignition is a Pazon surefire. Never checked each side independently, thought it was the "wasted spark" type. I thought maybe I was seeing a timing mark on the bend of right hand plug but not sure.
Jetting is 220 main, 106 needle with needle in lowest clip position, #3 slide and idle screw 1 1/2 turn out. What would be best method to slightly increase richness on left hand side? Like I mentioned most of this has been fairly low speed riding around town and back roads. I doubt if it has been above 3/4 throttle much at all.
Jetting is 220 main, 106 needle with needle in lowest clip position, #3 slide and idle screw 1 1/2 turn out. What would be best method to slightly increase richness on left hand side? Like I mentioned most of this has been fairly low speed riding around town and back roads. I doubt if it has been above 3/4 throttle much at all.
Fast Eddie
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I would suggest that your problem is linked to your use of wooden HT plug caps...
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The one on the left looks correct, the one on the right looks rich. The indication is the black ring on the porcelain right down inside where it meets the metal. It should always be there, unless you are getting silly and looking for max power. Ignition system problems can give the same symptoms as jetting problems. Also oil on the plug can cause you to misread it. In the plug on the right, the black ring is too high and dark - are they both the same heat range ? You might have a carb frothing problem.
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my 2 cents which with infaltion is not worth its thin copper coat.
First off those are not really problem showing plugs just normal range of various asymmetric factors.
My impression is L plug a bit on the lean side with slightly advanced hotter ignition timing. The R plug looks like there may be a dash of il exposure as well as slightly less hot spark current timing plus what ever mild carb issue exists. I give nod at 1.5 pilot turns as indicates optimal baseline fuel level and clear pilot passage. Two additional things to ponder, one the 15% less hot-intense spark on the reversed plug polarity side of a wasted spark ign and two the height of the spray tubes, even though Amal said did not affect mixture draw, yet we know just a notch can matter so way not height for faster more inital spill out from shorter tube heights. Likely have to get box of new plugs and really do a rpm limited zone chop - again and again till seeing what might be doing what.
First off those are not really problem showing plugs just normal range of various asymmetric factors.
My impression is L plug a bit on the lean side with slightly advanced hotter ignition timing. The R plug looks like there may be a dash of il exposure as well as slightly less hot spark current timing plus what ever mild carb issue exists. I give nod at 1.5 pilot turns as indicates optimal baseline fuel level and clear pilot passage. Two additional things to ponder, one the 15% less hot-intense spark on the reversed plug polarity side of a wasted spark ign and two the height of the spray tubes, even though Amal said did not affect mixture draw, yet we know just a notch can matter so way not height for faster more inital spill out from shorter tube heights. Likely have to get box of new plugs and really do a rpm limited zone chop - again and again till seeing what might be doing what.
Both my plugs look similar to the right hand example, and I personally think they are perfect. No melted or eroded ground wire in evidence, no balls of aluminum, and although I see a couple of small black specks (?), I don't see evidence of peppering on the porcelain. The right hand plug though not looking bad makes me think a bit of oil is getting into that cyl, certainly not much and not enough to keep me up at night. Much harder to read plugs these day with out lead additive as a helpful indicator. I think white is the new tan but be careful of mechanical damage to the plug for an indication of too lean. I now and then take a peak in the spark plug holes with pistons at TDC to see what kind of deposits are sticking on them, a small focusable Maglite works well for that.
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htown16 said:
With wasted spark the timing should be the same on both cylinders although if the cam bush is loose funny things can happen.
Might want to compare cylinder leakage or compression first.
Check and make sure both floats are the same level and if they are then I would probably move the needle clips richer on the left and leaner on the right. Jim
htown16
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Will check the float levels. Not much I can do on the left side needle clip, as it is bottom position. Run a BPR 9es on the left side?
Don't know if it is contributing to the assymetry, but the right side plug is running in an oversize big cert insert that almost touches the valve seat.
Don't know if it is contributing to the assymetry, but the right side plug is running in an oversize big cert insert that almost touches the valve seat.
A
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Ensure there are no manifold air leaks then check that the slides open at the same time using drill bits then confirm there is equal vacuum at the same throttle openings. If using two gauges, swap them across to check for gauge variance.
Ta.
Ta.
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On a Norton road bike I still believe the plugs should look like the ones on the right. Mine do. I use B7ES plugs though so I might be running a bit richer than you. I have put 18,000 miles on my bike that way with no trouble. My bike uses only 4.5 liters per 100 Kms and sometimes a bit less. It works from sea level to 10,000 feet. I didn't look at the plugs when I was at 10,000 feet probably they were black, but it ran, idled an started really well. At 10,000 feet the main jet was to rich though, you could go a bit faster by closing the throttle. I like the mixture to be a bit rich when wide open to protect the engine. My aim was to have the bike run pretty lean in the mid range, rich on the main jet. The low speed running is set mainly to try to have a smooth pick up from closed throttle to acceleration.
Maybe if you put a new plug in and do a quick test of the main jet it should look like the one on the left. On modern fuel injected liquid cooled bike like my Triumph Sprint the plugs look like the ones on the left all the time. It was the same even with my Guzzi V11 Lemans (air cooled fuel injected)
Maybe if you put a new plug in and do a quick test of the main jet it should look like the one on the left. On modern fuel injected liquid cooled bike like my Triumph Sprint the plugs look like the ones on the left all the time. It was the same even with my Guzzi V11 Lemans (air cooled fuel injected)
FWIW, I have used bpr6es,7,8,and 9. Sometimes a 7 in one and a 8 or 9 in the other. No 2 Norton's breather exactly alike, and you can expand this to no 2 cylinders breath exactly alike. As Comnoz states, this can apply to jetting also.
No set rules here. Although your plugs look not the same, that is not to say that either look particularly bad. Maybe one a little richer or one a little leaner. Swap them and see how they look after a run. Maybe go up or down one number on one cylinder to equal them out if you so desire.
No set rules here. Although your plugs look not the same, that is not to say that either look particularly bad. Maybe one a little richer or one a little leaner. Swap them and see how they look after a run. Maybe go up or down one number on one cylinder to equal them out if you so desire.
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If you are tuning your bike for performance, it's better if you use hotter plugs when you are adjusting the jetting, then fit the colder ones for normal use. That way when you look for the black ring on the porcelain, you tend to stay safe as you lean off the mixture.
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Generally racers fit cooler plugs as they tend to run em hot and wild while street use gets hotter plugs to make up for the slow low temp rarely holding WOT to redline and top out down an open. There is a tedious science and art to reading all the features plugs can indicate so enjoy the learning curve balls.
htown16
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Well checked the float levels and actually found the opposite of what I expected. The float on the left hand or leaner side actually looked like it was set a bit high. These are stay up floats and it stood proud of the top of the float bowl a bit. This carb has always had a few issues, sometimes when you tickle it, it will continue to drip gas for a while. Also, if you refer to my other thread (left-gas-tap-t22083.html) you can see where when I accidentally left the taps on it filled the sump with gas in few hours, indicating a float wasn't working properly. When I caught the fact the tap was on, the left hand carb was wet.
Anyway, I gently bent the tangs until the top of the float was even with the top of the bowl in the front. I then used my u-tube rig to check fuel levels on both sides. They both now match at a shade below .25" below the top of the float bowl, the bottom of Amals range. I found out on my Bonneville with the stay up floats that the bike runs the best right at the bottom of the Amal .17 to .25" recommended range.
Anyway, I gently bent the tangs until the top of the float was even with the top of the bowl in the front. I then used my u-tube rig to check fuel levels on both sides. They both now match at a shade below .25" below the top of the float bowl, the bottom of Amals range. I found out on my Bonneville with the stay up floats that the bike runs the best right at the bottom of the Amal .17 to .25" recommended range.
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