puch e50 w/polini
In order to set the fire mark on my magneto to be ~.7 inches before the TDC center
I have to have my points pretty wide - probably like .8mm
i guess i could lower the point gap a tiny bit and move the stator all the way advanced - but i only have a tiny bit now til it is ful advance
what are the implications of this?
also what is the most reliable - polini timing setting?
does a timing setting for stock puch correlate with correct timng for polini?
You should set your timing by moving the stator assembly. Point gap can make minor changes in timing but it is not the proper way to do it. Widening your point gap shortens your DWELL which is the duration of charging received by the coil. This is probably not significant but making everything correct can't hurt either.
How does it run?
ive found that points are crazy. well on my vespa atleast. im not sure about other brands but on vespas, you take the thikness that the manuel says and you go a couple feeler gauges up. you slip the gauge in and tighten the points to that. when you take the gauge out, it somehow goes to the specified thickness. it does not always work though. it still needs perfected. also, if you want better performance, you advance timing a tad. maybee one or two feeler gauge sizes, depending on the intervals. not much. so ya. that is basically the most knowledge you can knock out of this 14 year old's head. my attention span isnt big enough to further perfect the technique haha.
and sorry about the spelling i accidentally hit the post button before the spellcheck.
i'd go with full advance and smaller point gap
my timing will not be correct if i set my point gap to what is suggested.
That is the issue.
Also, I hate this talk of "full advance" with point gap correct. If I set my point gap correct there's no way I will have advanced the timing more that what is suggested in the puch manual. No matter how far the stator is in the advance direction.
I will actually run retarded.
The moped runs ok I guess. Its rich for break in of the polini kit, of which I am super paranoid about seizing.
Also, big hills suck to break in on - either you have to coast down them and throttle and brake not to seize or blast up them full throttle to even make it up the hill)
yes, it may be an issue. The points gap determines the dwell of the coil Dwell sets how saturated the ignition coil gets. Wtih a dwell that's to short, you will have a weaker spark at high rpm. With a dwell that's to long, you could potentially burn out the coil. (though that's unlikely inthe case of magneto powered ignition)
Long story short, yes, it matters.
OK. so why does this happen?
Is because my points are worn and I need to replace them?
What is the ideal dwell time? Can you tweak it out? IS there a 2 stroke runing article on this?
if you've got a 50 high comp head, don't run a full advanced stator position with that .8 points gap. Death will come ripping to your case and it's insides....so I've heard...from a friend...who I don't hang out with anymore cause of that.
I'm doing only okay at the moment with my points at .018, stator set back from full advanced enough that I can see the the edge opening of the screw hole. I was running that way with a stock head, and it sucked but I was safe but couldn't come anywhere close to wot, and I'm currently still running that with a 70hc head and like I said, it's only okay. I totally don't trust it, but it's working as a great starting point while I try to figure it out.
.8? really? i once tried mine at.024 and it wouldn't even start till I got it down to .018. But .8? that can't make the world a better place.
This is a good thread and I want more info.
Anyone have any good reading links on dwell and its effects? I've been having a lot of fun with timing lately (NOT!) and I want to know everything.
THough I'm not sure on the theory of what works and what doesn't, I've found a position 1/2 between the middle and full advance works well on polinis. With that said, I've been having a hell of a time getting the power I want and my bike is performing poorly. Sure it still goes fast but it takes far too long to get there.
I'll try some stuff out tomorrow and report back. Now someone post some theory links.
i can tell you right now zack you need to advance your timing. personally.
I think the stator position absolutely does not matter - (except to change one of the following two slightly)
That only two things matter are:
1. Dwell time
2. And the piston's position when the points open up.
For instance you could have a set of new points and a set of wor but fine working pointing
if the point gap was the same you could have the stator in completely opposite extremes AND have the piston fire at 2mm BTDC for both.
Effectively making the mopeds have the same timing with different stator positions.
right?
So, let's focus on the implications of dwell time AND the heating differences of advanced and retarded timing.
Personally, I would like to set my timing at the position where my moped will run the coolest, regardless of any other factor.
"If I set my point gap correct there’s no way I will have advanced the timing more that what is suggested in the puch manual. No matter how far the stator is in the advance direction." ????
I think the stator position absolutely does not matter – (except to change one of the following two slightly)
That only two things matter are:
1. Dwell time
2. And the piston’s position when the points open up.
umm, i think you're confused.. your both your first statements contradict #2: moving the stator, moves the points in relation to the cam on the crank shaft, which means it changes the "pistons position when the points open up", as you put it, or, changes the time at which the points open up in relation to the piston at tdc, ie, sooner or later, ie changes the _timing_. you change the timing by moving the stator. you change the dwell time by changing the point gap. geez.
Soundz to me like the rub block aka cam follower of your points is worn down. When you put in new points put a dab of grease on the cam and rotate the crank in running direction to put a deposit of that grease on the leading edge of the cam follower to reduce wear
I set the points very slightly wide...this advances the timing a few degrees, and allows for rubbing block wear, which slowly retards the timing. Advanced timing may slightly improve performance, and slightly improve the chances of burning a hole in the piston. With most fixed timing ignitions, the point gap is not too important, as long as it is not so close that the points arc and burn. Old V-8s with points did a lot more opening and closing at 75 MPH then a little single two stroke single at 25.
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