GP3 COIL

[bmk]

How long, actual engine running time, should you get from a genuine polini coil?

The chinky one lasted a few minutes and the genuine one i replaced it with has lasted 12 hours.

Is this normal?

As i understand it the polini coil should deliver 16 to 17000 rpm.
I have a pet2000 rev counter and it reads at just over 20000 rpm and thats under load.
Anyone else getting these kind of figures or is my counter telling lies?

If the counter is accurate is this the reason i'm frying my coils?

Your input will be greatly appreciated,
Ken.

[tony811976]

i doubt the engine reached that sort of revs.
is the rev counter set for a single cylinder? is it that type of counter?

[faucon]

what it give at idel engine speed, it may be around 3500 rpm, if you read 7000 (double) maybe your tachymeter not setup at 2 stroke. but i learn that the coil may produce a wasted spark according to recharge itself, but i dont know alote about that. i also read that the genuine coil dont like heat. personnaly, i run a chines coil, i feel like its running fine and strong, my engine never overheated, i dont read the wasted spark things on my tachy, but im not able to read the max rpm (bad resolution), but i read 14000 rpm last year, but whit wrong biger jet, so im sure now its going faster. i may need to film it under load.

[bmk]

tony811976, yes the rev counter is set for single cylinder (21/42) two stroke. Its an oppama pet 2000dx which was recommended to me as the easiest to use on minimoto's. ( i've seen a few people using them also. )

faucon, the "wasted spark" you speak of, would that register on the plug lead though? (this is where i have the rev counters lead wrapped). As this is after the coil windings any pulse would result in a spark firing at the plug would it not?( leading to a revolution???)

Anyway, my initial post was because i thought i had fried my polini coil.
The bike would start but would die and /or backfire and die after only a few seconds.
As i had fitted an NGK B9EGV racing plug at the last track session and everything looked fine with the plug, i assumed the coil had broke down.
However i have fitted another coil and the same things would happen as previous.
I then swapped the racing plug for a standard B9ES and everything is back to normal ;D

Which now leads me to ask, what is the life expectancy of a racing plug in these machines?

Cheers,
Ken.

[faucon]

bmk said:

...
faucon, the "wasted spark" you speak of, would that register on the plug lead though? (this is where i have the rev counters lead wrapped). As this is after the coil windings any pulse would result in a spark firing at the plug would it not?( leading to a revolution???)

....

impedance

when you saw, wrapped, its maybe like my tachy, 3 to 5 turn around the spark plug wire of one wire of the tachy, and the other wire of the tachy must go to the ground, frame.

if its that way its setup, it work by impedance, the wire you wrapped read the magnetic field around the spark plug wire that occur at every spark. so there no way your coil be damaged this way.

sorry about the wasted spark fact, i see it on a "uk" web site, but the site was down, and the mec tell he dont know alote about electric, but know there a heat/faillure issue. sorry.

[bmk]

faucon.
Only one wire for my tacho.
You can either crocodile clip it to the plug lead or wind the wire three to five times around the plug lead.
Having read the small print, (in the trouble shooting part of the manual) it suggests that if an erroneous reading is being given to wind the wire around a frame member instead.

I will try this next time out and let you know. ;D


Ken.

[bmk]

This is really starting to mess with my head now

I've been informed that the gp3 does spark twice in one revolution and that i should set my tacho for a twin cylinder two stroke (22/42 mode setting) and this will give me the correct reading.

This would mean i'm only getting 10000rpm from the motor and that can't be right. I've tuned a cag to 11400rpm under load and this gp3 makes it look like its going backwards.


Can anyone help clear this up?

[ninjanut]

Hi bmk
what you have been told is correct regarding the twin spark.we,ve got our pet 2000 set to 22/44 and get a max reading of 16950rpm.if you use the 21/42 setting just double the reading for true rpm

[bmk]

Hello ninjanut, thanks for the reply.
I got talking to a couple of blokes at Warden Law, one of them had aPet2000 on his kart.
I mentioned the problems i was having with mine and he suggested to try the twin cylinder option also.
Weather permitting i'll be up there tonight to try it out. ;D

Thanks for your help,
Ken.

[hally]

Hi
when myself and markyb went to see the scott `dude` finlay he said to us that the genuine polini works on `the waste spark system` and the chinese dont, he had troubles picking up readings on the dyno at times and ours peaked out at just over 16,000 rpm on the dyno pulling over 8.5 hp when he had finished playing with them

[hally]

what is a `waste spark system is`
read on.
on a non waste spark system, the ignition spark once only at the desired time(2 stroke, every 2 strokes,,4 stroke every 4 strokes), but with the `waste spark system` the ignition sparks on every stroke,

[bmk]

I can't for the life of me understand why you would need to do this on a two stroke though.
You are drawing fuel into the chamber even on the exhaust stroke so why fire the plug?
I'm by no stretch of the imagination an expert but i have a certain grasp of the basics and i'm still none the wiser.