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[Tim NZ]

Worn out shaft bushes will give rise to timing flutter with any ignition trigger, reluctor or points, including a Bowyer. A Strobe-light, or better still an oscilloscope confirms all.


AA problems (dry rust wear) is negated by routine maintenance; lubrication. Lack of which in turn is the primary cause of issues with so-called weak return springs and ignition timing issues.


The occasional squirt of Chain-lube in behind the points plate goes a long way, as to does a drop of oil on the felt of the points heel wick.

[Bullet Whisperer]

Worn distributor bearings will adversely affect an ignition system using points, where the opening point and gap could fluctuate. You would need a hell of a lot of play to upset a Boyer, but let's not forget the slop often [and usually] found in the timing gear train. I once clocked 11 degrees of timing fluctuation with a strobe on a Lucas SR1 on a 500 Bullet, at full advance [4500rpm] because of the backlash in the timing gears and even a Boyer system will not fix that one. My road going Bullets all have points, rarely looked at and never any trouble, but the timing has to be right, whatever you use. That said, I think I would be taking a look at the carb and the pilot circuit in particular, going by the symptoms described in the first place. Also, what Gwilly said.

[Clement]

I am pretty sure that I had my CI (cast iron) 2003 Bullet on the right timing - I followed the instructions of our host re ignition timing and using this dead centre tool (part E003) aiming for BTDC 0.8 mm before TDC.I established moment of opening points by using Zig-Zag rice paper used for rolling cigarettes: the moment I could pull this thin paper strip out the points were opening. When some kickback occurred I thought to retard slightly as suggested also in this post, so turned the back plate slightly (1-2 mm) clock wise to fire later. To my surprise this did not work, if anything kickback more vicious.
I don't have up and down movement in the distributor shaft. I now wonder if the automatic advance unit lying behind the points is knackered.....
C.

[Gwilly]

Thanks Adrian, so its a "see eye" iron barrel same as mine..

Clement it would take only a moment to pull the points plate forward and examine the auto advance..

Should be able to turn the cam clockwise a few degrees with your fingers, when released it should snap back fairly sharply..

Possible a spring has broken or the cam is seized in the advance position, easily sorted..

Chain lube ala Tim sounds like a nice idea..

Perhaps check the resistance through the plug cap if its an R type, weak spark at kick over speed will wet the plug..

[Clement]

I think that I have solved it: pulled the points plate forward and checked the advance unit as suggested - all okay, not stuck, but noticed some oil on it which must have come from the primary case - is this tolerable? Then re-set the timing but noticed that I had a very weak and intermittent spark; fitted new HT lead -things seem to run a lot better now; will still check the carb. C.

[Clement]

mistake here: oil on the advance unit of course seeping in from the driving chest? C.

[ric]

There is no oil seal on the shaft so oil can find its way from the timing chest to the advance and retard unit.

I used to set my timing on full advance because at or near to top dead centre the piston hardly moves at all so any inaccuracy is greatly magnified. Closest I managed with one of those tools was within +/- 5* of TDC. Setting the ignition at full advance also takes into account any wear in the advance and retard unit.

Try setting the ignition at 9.5mm with the points fully open.
Just for info whern you rotate the back plate by 2mm you alter the ignition by just over 7*

[ric]

Correction

Should have rear try setting the ignition at 9.5mm with the advance and retard unit fully open.

[ric]

*read* not rear.
Time for coffee methinks...

[Adrian]

Please Mr. H, may we have an edit facility on this board?



The problem of worn bronze bushes in the contact breaker drive (distributor if you must!) is well know. Swiss tuner Fritz Egli brought out an improved version with proper bearings, then the factory finally cottoned on, and applied the same modification to all LATE model 500 classic/cast iron Bullets. I no longer have my spare one, but they shouldn't be too hard to get hold of. They also have an oil seal behind the advance and retard unit.



A.