Hitchcocks Forum

For many years I have set ignition timing by ear for fastest/smoothest running at idle, then left it to the centrifugal advance to deal with the rest. This seemed to result in being somewhere near quoted static advance as confirmed with plunger down the plug hole, so I accepted it as okay.
However, recently I have cobbled up a (temporary?)simple lever to alter timing whilst actually riding in order to determine an "optimum" setting under road conditions.
My "optimum" setting gives much smoother running both under acceleration and steady running with much less mechanical noise and also a more subdued exhaust tone in mid range than I have ever had before. It certainly gives the impression of being kinder on my bottom end bearings with reduction in harsh clatter!
"Optimum" appears to be a more retarded setting than I used previously, but whilst giving an extremely consistent tickover any temporary advance does lead to a significant increase in idle revs which gives me some doubts about it.
The centrifugal mechanism is working okay, so I am wondering if I have been running way too much advance for ages - or do the standard advance curve and stops just not suit the engine very well?

With out a degree wheel and strobe, one will never know for certain...


But yes, smoothness and mechanical quietness are directly linked to ignition timing and advance setting/range.

Click on Technical Notes on the menu on the left; then Electrics, Ignition timing (Indian Bullets with points). There is a note(in blue) stating it is better to set timing at fully advanced position.

I always believe in setting static timing as at full advance. The bob weights are in that position most of the time so it makes sense. The addition of a manual lever though does give you the advantage of being able to retard the ignition on a long pull up a steep hill. It allows you to do what a vacuum advance module would do to the last of the old fashioned points and coil ignitions. My old AJS 16MS had both bob weights and a manual lever on an N1 magneto set up and it was highly satisfactory.

The setting by ear method at tickover will give too much advance, on any manual advance bike you will find that tckover speed increases when you advance using the lever,

It would be interesting to see pictures/details of your set up.

In these wonderful modern times that we live in we have this really clever and exciting piece of equipment known as a Dyno.
It's actually possible to see exactly what advancing and retarding the ignition does in real time on a computer screen and how this alters the power output at the rear wheel... no ifs, no buts, no guessing.



This graph shows the increase in torque after adjusting the ignition on an Enfield I modified a little The amount of midrange torque actually increases by over 100%.
Modern technology. Please try and embrace it and benefit from what it can offer

Thanks for replies folks, all welcome and constructive! It will be interesting to compare my setting with the "fully advanced" 8.5 mm. and I'll post result.
Pete, I called my mod temporary because at the moment it works with the points cover removed. Looking at plate, I drilled and tapped a small hole in the area above the condenser mounting "round nut" and inserted a short length of stud which I staked on the back so it remained flush and clear of weights. I then put a nut fully down on this. A suitable light strip of steel around 4 inches long was drilled right at the end to fit over the "round nut" and again further up to locate over my bit of stud, where it was secured with a second nut. The two backplate securing studs were loosened and made to be a friction fit with spring and plain washer, and I am now able to adjust timing with the lever which pokes upward behind the cylinder, within the constraints of the slots.
If this proves useful long term then it can easily be refined, but for now I can reach down easily enough to experiment.
Ric, thanks; certainly your suggestion would be the best solution, but maybe a bit hi-tech for just pottering around lanes at 50, and certainly for someone who has yet to master posting a picture for Pete on here!!

Thanks for that p.
Should you want to post a picture; you need to upload the image to Photobucket, grab the html of the image which can then be posted straight in here.
You could always email it to me if you want [email protected]

I'm doing this on the phone so it might not work but this is the pic of p's setup. As he says, it's a bit of a prototype.