Topic: timing light

[yesteryear]

Hi all,
Just a quickie when strobing my timing on 1 and 4 the light is fixed steady on 2 and 3 it fluctuates.The advance unit, points,condensers,coils and caps are all new
Honda stock (except caps).No problem with full advance all lines up OK.Anyone have any ideas why?
Regards
yesteryear

[yesteryear]

sorry all.

forgot to mention cb750k4 bike
cheers

[trueblue]

When your doing 2-3 the pick up for your timing light isn't touching either 1-4 lead is it.  If it was the advance unit causing this it would do it on 1-4 as well, because it is a shared system between the 2 sets of points, possibly a crook condensor, or maybe a worn out set of points on 2-3, off the top of my head I can't think of anything else that could cause this I hope this helps

[yesteryear]

Thanks trueblue.
No I make sure that the pickup is not touching but i originally thought dodgy condenser.Replaced that and points are only 80 miles old still the same.What I might try is swapping condenser on 1 and four and see if that proves something.
Thanks anyway
yesteryear

[trueblue]

When tracing a fault like this try to isolate the systems, for instance the advance mechanism is common to all cylinders so any fault with it you would expect to see a fault on all cylinders, but the points and condensors are seperate so they are possibilities, if you move the points and condensor to the other cylinders and the problem follows then that is your problem item.  Only move one part at a time so you can isolate the issue easier.

[trueblue]

also check resistance in you HT circuit, and swap your 2-3 plugs with your 1-4 plugs and check again, unlikely, but a possibility, there isn't too much that could cause this but make sure you cover everything.

[yesteryear]

Trueblue cheers.
Funny thing as I recall before I changed all the old for new it did it then also.Maybe I just have to live with it as it does not affect performance and idles spot on.Even with fluctation you can still set the timing ok.
Yesteryear

[trueblue]

No worries mate, if it runs fine I wouldn't worry about it too much, but that wouldn't stop me looking, it is definately an odd problem though.

[Bodi]

if it has an inductive pickup, these tend to be sensitive to polarity... try flipping it over on the wire so the cable goes through the clamp the other direction.