Hitchcocks Forum

...can you help please?


A little while ago, some of you might remember that I posted about ignition failure on my 2006 500 Classic, which turned out to be the points going O/C for no apparent reason. Everyone was v supportive, I replaced the points, and all now seems fine.


Almost...


Since replacing and setting the points gap,  two things seem to have happened. Firstly, the idle is much slower than it used to be. I've no real complaints, as the idle is totally reliable, but it is very slow. Secondly, the bike now starts much better, needing much less effort on the kick starter to spin the engine. Why is he complaining, you may ask? Sounds good to me....


Well, yes, but taking these two things together this seems to me to indicate that I may have over-retarded the ignition by bodging the points gap.  It is very difficult to check where the point of maximum opening is, as the cam form is basically a lopsided semicircle, with no obvious "highest" point. I think  I've got it right, but am not sure.


My question therefore is: is it possible to make that much difference to the ignition timing simply by furkling with the points gap? The bike runs well (albeit feeling a little flat on occasion between 50 and 60). It does not seem to be running hot, exhaust note has a nice tone, exhaust header doesn't seem to be blueing. I have not touched the actual ignition timing plate on the dizzy. Any ideas would be welcome, particularly on reliably finding the optimum points gap position.


Cheers


TimG

Hi TimG. I sold my 2007 535 a few months ago, but I recognise your frustration - running well but don't know why.


Assuming you did not move the distributer backplate when renewing your points, the timing is basically unaffected, but restoring the correct gap does have small effect and with a more reliable opening point, engine runns smoother. I take your point about difficulty to detect when points are on the top of the cam. Taking the plug out and using the back wheel to turn the engine over makes it easier to see the points are fully open, at which point adjust the gap. Readig the Snydal manual gives excellent advice also. (Now with an EFI, no possibility to practice the above . Yippee.)


Cheers

The points gap can have a significant effect on ignition timing: a wider gap inevitably advances the timing, and a narrower gap retards it.  After re-setting the points gap, the timing should be re-checked.


(Some 2-strokes used adjustment of the points gap as the only routine way to adjust their timing.)

I gave up with points long ago, fit a Boyer once and forget it. My engine starts and runs far better as well.


Some owners say with points you can always do something to get it going, but I've had Boyer conversions on all the bikes i've had that originally had points since 1973 and I have never had a Boyer fail.

Hi guys ------- just out of interest sake, if you look at an engineers 6" or 12" ruler then the width of those etched lines is about 10 thou ie 0.010" so the 0.015" for your points is half as much again. NOT MUCH at all really. So timing AND gapping of points must be done accurately. Having said that--- the old fag-packet would give a get-me-home setting along with the dirty thumbnail for the plug setting  ( 0.025" ) or the thickness of your engineers ruler. 

As said in the previous posts the points gap can effect the timing slightly. 


At risk of teaching you to suck eggs, the timing is set when the points open rather than when they shut. The exact point they open can be ascertained by use of a bulb wired between the live feed to the points and ground.


The bulb illuminates the instant the points open. 

-----------sort of like when the pub doors open as well !!

Tim and John an' all - Another (easier) way of determining the exact moment the points open is to get any old portable radio and 'tune' it in between stations. With the ignition 'on' the radio will give a loud crackle the moment the points open (even with suppressor cap fitted).


Riggers