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Re: Ignition Timing Clarification

You can adjust your points a little by enlarging or decreasing the gap between the points, this way you can adjust the ignition until is't 100% ok. But don't over do it, this only works when you are already very close to the correct setting of the points.

Henk

email (option): ahum@quicknet.nl

Re: Ignition Timing Clarification

FWIW I also use a .001" feeler gauge.
I have an old set of pointy ended ones and I let them ha and rotate the armature till they just start to slip down under their own weight down.
They are a small set about 10 so they are the ones I keep with the bike.
This way the timing is fairly well constant.

email (option): bsansw1@tpg.com.au

Re: Ignition Timing Clarification

Quote thing won't work

In your first paragrapgh you say you did the ciggy paper thing then adjusted the max gap to 12 thou. Its the other way round. Set the max gap first otherwise the one will undo the other if you know what I mean.

Re: Ignition Timing Clarification

I use one of the electronic gizmos that senses the opening of the points...It has an LED colour change from red to green as the points break but usefully also has an audible indicator...It's very easy to position the points exactly before connecting everything up and eliminates the need for 'feel' thus improving accuracy and repeatability...

After the timing is set it's not necessary to touch or even look at it to determine the exact time that the points open, leaving you free to concentrate on gradually coming up to the correct piston position when checking the setting...

I can't say I tend to use feelers or cigarette papers anymore as a first choice....

I also do the timing with the head off when in the workshop, using a depth micrometer to accurately check piston position initially and to check the setting once done...

Personally I've always stuck to the manufacturers setting of 7/16" BTDC (fully advanced) and like to get within .010" either side of that...

The bikes run pretty well using those settings and whilst I suspect a small change to take account of modern fuels MAY be beneficial I won't make a speculative change to settings without being able to confirm by measurement that the engine is actually running better...

That would require some back to back comparison tests on a dyno to assess the effect of any timing change on peak power, revs and peak torque...and so far to my knowledge no one has done that.

Any statement regarding the results of changes to settings without the results being physically measured would, in my opinion, be pure speculation and therefore an inherently inaccurate procedure...Ian

email (option): ian@wright52.plus.com

Re: Ignition Timing Clarification

Ian can you provide a link to that gizmo? One of our Asian forum members was going to make some and offered to send me one, but it never materialized. As you say! The 'hands free' audio/visual thing would be a bonus. Cheers Ron

email (option): ronpier@talk21.com

Re: Ignition Timing Clarification

Hi Ron...The company that made mine is no longer in business.. However, here is something pretty much the same on e bay...

E Bay 192509324933 ...........Ian

email (option): ian@wright52.plus.com

Re: Ignition Timing Clarification

Cheers Ian! I've treated myself.:relaxed: Ron

email (option): ronpier@talk21.com

Re: Ignition Timing Clarification

If you do the timing with the head of knock up a bit of strip steel held down with a head bolt against the cylinder face that has a threaded hole with a bolt over the bore, adjust the bolt to give 7/16" contact with the piston and with a bungee on on the kick starter and in gear the engine is set and will not move. Adjust the mag at your leisure.
Richard

email (option): richard177smith@btinternet.com

Re: Ignition Timing Clarification

Thanks for the feedback, everyone. Ian, thanks for the gizmo link! I treated myself to one, as well.

Re: Ignition Timing Clarification

Richard Smith
If you do the timing with the head of knock up a bit of strip steel held down with a head bolt against the cylinder face that has a threaded hole with a bolt over the bore, adjust the bolt to give 7/16" contact with the piston and with a bungee on on the kick starter and in gear the engine is set and will not move. Adjust the mag at your leisure.
Richard
Nice idea to put the engine at hold, Richard. Does is work well?? Think you have to compensate for some play in the timing gears, don't you?

Just thinking that you don't even have to take the head off if you put a long 1/4" bolt through the timing hole, find TDC and turn in 7/16".

email (option): m.wijbenga@hotmail.com

Re: Ignition Timing Clarification

I seem to remember that Hans had that idea with a stop bolt in the the timing hole (Might be in the technical page?). The only problem is, when you nip the pinion nut up, the piston will move backwards. Locking in gear is an idea, but I'm not sure how much backlash there will be in all the drive components? Ron

email (option): ronpier@talk21.com

Re: Ignition Timing Clarification

You're quite correct Ron, the engine does move backwards when the mag drive nut is tightened (and it usually does move)...Ian

Ian

email (option): ian@wright52.plus.com

Re: Ignition Timing Clarification

Yes, but just thinking.... you can simply stop the engine from turning by putting a cross bar between the enginesprocket and clutchsprocket.

If you make that crossbar adjustable you can slowly turn the crank untill the piston touches the bolt which sticks through the timinghole.

The crossbar will than take the force when the the magdrive nut is tightenend.

So think holding the engine firmly in the correct position should not be the problem, don't know about backslash/play in the gears though. Will try soon. :slightly_smiling_face:

email (option): m.wijbenga@hotmail.com

Re: Ignition Timing Clarification

I think I'll stick to the usual method. Seems a lot of effort to remove the chain-case and make some sort of locking bar to me. The idea of a pre set bolt in the timing hole sounds good though. At least you know when the piston has reached the exact spot each time. Ron

email (option): ronpier@talk21.com

Re: Ignition Timing Clarification

I made my own timing tool using the below plans.

http://www.aeroelectric.com/articles/Magneto_Timing/Jim_Wier's_Timing_Fixture_2.jpg

This is for an aircraft magneto tool, aircraft generally having dual magnetos, but you just omit one of the legs of the circuit.

Its quite a good tool, sadly, it doesn't stop me getting the timing 180 degrees out :face_with_rolling_eyes:

Re: Ignition Timing Clarification

Sorry Gerard. I don't think that will make sense to most of us? Ron

email (option): ronpier@talk21.com

Re: Ignition Timing Clarification

Has anyone explained to Aaron that the ignition advance cable of the magneto must be on the right side of the points ?
And not on the left side (that would turn everything around)

Re: Ignition Timing Clarification

Well that is a good point Michael! Although the instructions clearly state to set the timing with the lever at full advance. The correct magneto will have a tight wire advance (cable position at the rear most part of the mag and pull the handlebar lever towards you) However it will work just the same with a slack wire advance (Cable at the front of the mag, push the lever away)....Probably teaching granny to suck eggs here! Ron

email (option): ronpier@talk21.com

Re: Ignition Timing Clarification

You reject the idea rather quickly, Ron, still working on it....:smile: :smile:

Just made a simple adjustable cross bar from a piece of stud, a nut and a tube. The adjustment gives the opportunity to fine-turn the crank up to the 7/16" BTC point or to a pistonstop and will keep it there firmly when fastening the mag-nut.

IMG 4172

My engine has no piston at the moment so i cannot test it fully and find out how it reacts on the backslash/play in the geartrain but will be soon and be back here.

and yes it means removal of the chaincover, but for me that is one of the last items I put on the bike anyway.

email (option): m.wijbenga@hotmail.com

Re: Ignition Timing Clarification

Well I wouldn't reject it out of hand Michiel, but I also wouldn't bother to remove my chaincase if I had to reset my timing. But definitely worth thinking about during a period of engine rebuild. Especially after you've done the groundwork to prove that it works perfectly :relaxed:

Regards Ron

email (option): ronpier@talk21.com

Re: Ignition Timing Clarification

Michael
Has anyone explained to Aaron that the ignition advance cable of the magneto must be on the right side of the points ?
And not on the left side (that would turn everything around)
I have the right-side/tight cable advance and know to check/adjust with lever at full advance. I neglected to note that in my original query, so thanks for double-checking!

Re: Ignition Timing Clarification

['Has anyone explained to Aaron that the ignition advance cable of the magneto must be on the right side of the points ?
And not on the left side (that would turn everything around)...]'

That is all explained in the article on ignition timing in the 'Technical Section' of this site...The article covers from basic principles through to setting the ignition...Ian

email (option): ian@wright52.plus.com

Re: Ignition Timing Clarification

Why not go about it the other way round ,piston at T D C points set 12 thou lever full retard points just opening and advance as needed when under way,that is how we used to do it, bearing in mind these engines are hardly F1 .

Re: Ignition Timing Clarification

To my mind Charlie, whether it's a racing engine or stationary engine, the ignition timing must be set accurately for maximum performance and more importantly, lack of damage. Surely it's just as much effort to set the timing at TDC on full retard,(which will only set the timing by guesswork) as it is to set it properly. :confused: Ron

email (option): ronpier@talk21.com

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