classic motorcycle forum
Motorcycle Discussions => British Bikes => Topic started by: dynamic on May 18, 2021, 06:50:35 PM
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having now done just 1000 miles on my machine since a full rebuild SRM timing side bearing / new sludge trap / crank regrind / rods /new cylinder / hepolite pistons / rings / head uprated to unleaded / valves /guides / springs / Morgo pump ( dust caps were within parameters )
I do find after a run of 60 miles + ( champion N 4s ) the right hand plug is always sooty ? left plug is always a nice light brown electrode dark outer ( no soot at all )
I have a new concetric 620 on 180 main needle on middle groove starting is good tick over regular running Boyer charging is 14.4 + volts when revved
just curious about this uneven mixture situation ?
all input gratefully received
PS engine is not using any oil I have just changed from Morris running in grade to Morris gold 40 air filter is a standard new unit
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A trace of burnt oil can leave a sooty or dirty plug.
I found this out with a Commando, where one oil seal had 'fallen off' the guide.
Usage was too small to be noticeable/measurable. And not noticeable to the rider.
If you have someone follow you though, they may observe a puff of blue smoke now and then.
If its on acceleration its rings, on deceleration its valve guides is the general guide.
It may improve with more running in though.
Have you given it a few BRIEF bursts of full acceleration to bed the rings in like the instructions say ?
Try swapping the plugs over too ...
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Hi I do vary the running speeds up to 70 so far I will swap plugs over and see if theres any change
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Its that (brief) burst of HARD acceleration that seats the rings.
The gas pressure forces them into/against the cylinder wall ...
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thanks R just waiting for a non monsoon day to ride again
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had a 65 mile run yesterday with a slight AC turn on the airscrew plug chop now shows a near perfect colour
(electrode light brown, plug outer body light black )
I was using 2 year N4s now fitted with new N4s and purring along now
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Light black - now there's an interesting colour!
Glad it's running well.