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Ignition timing advancing with revs?

Posted: Sun Feb 17, 2019 12:09 pm
by Jackomad5
Hi, please help!

Currently trying to get my timing sorted on my LML malossi 166, ignition system is LML (separate coil and CDI) (fixed timing)

Timing is strobed at the 3000 ish rpm at 17/18

Thing is when I rev it high and the pipe kicks in the timing waaaay advances to well above 20. Is this normal? Surely this can’t be going on inside the engine.

I will add that I have melted a piston on this previously, however at the time I put that down to the timing simply being set to high to begin with, of course I’m now starting to question if this was the issue.

Appreciate any response! Cheers

Re: Ignition timing advancing with revs?

Posted: Sun Feb 17, 2019 12:59 pm
by eibargum
Iam relatively new to Vespas Jack so take all I say with a pinch of salt, I recently fitted a Polini 210 top end on my "apart from SIP road 2" standard PX, I strobed it to 19 degrees and noticed mine advances when revving it.

Re: Ignition timing advancing with revs?

Posted: Sun Feb 17, 2019 9:06 pm
by Jackomad5
Well atleast I’m not the only one eibar! :lol: I’ve known them to advance slightly when stobed but never to this degree

Re: Ignition timing advancing with revs?

Posted: Wed Feb 20, 2019 8:30 pm
by Jackomad5
Anyone any ideas?

Re: Ignition timing advancing with revs?

Posted: Wed Feb 20, 2019 11:00 pm
by Adam_Winstone
I had it recently and had to rescue it with a change of pickup and alignment.

Re: Ignition timing advancing with revs?

Posted: Wed Feb 20, 2019 11:54 pm
by Jackomad5
Adam, good shout but thing is I’ve swapped stator, cdi and coil all to no avail

Re: Ignition timing advancing with revs?

Posted: Thu Feb 21, 2019 8:49 am
by mick1
loose magnets in flywheel ?

worn bearing (causing crank/flywheel movement) ?

Re: Ignition timing advancing with revs?

Posted: Thu Feb 21, 2019 10:52 am
by Jackomad5
Cheers mick, cant see it. Motor has had new bearings and crank recently.
Sounds then as if this is absolutely something that shouldn’t be happening? As opposed to maybe an LML thing (might just convert to Ducati) Or maybe I’m getting a false reading somehow :? Aargh

Re: Ignition timing advancing with revs?

Posted: Thu Feb 28, 2019 2:57 pm
by Jackomad5
For anybody interested it turned out that it was the pickup or pickup height as Adam mentioned.

Both the LML stators I had gave me the problem. Tried a vespa stator, problem solved. Changed pickup on my LML stator and raised it to match the vespa stator and all is good!

Vespa wins