blown motorized bike carnage!

click on my signature link and go to the CDI page to see the ignition curve of the standard ignition as well as that of the Jaguar CDI
the link did not seem to take me to where I wanted to go, can you send me a more direct link to the location of which you want to send me?

very interested in the stock timing curve and advance vs rpm

im an oldschool guy, so I prefer mods such as compression and ignition. I have looked at your product before but not found as much comprehensive info as id of liked.
 

okay, I have read through your info. I can see where you warn against the timing advance with compression, though this problem is not localized to just these two stroke motors alone. I do a lot with small block carbed motors and they have advance curves much like this where they increase as the rpms increase with no retard. while the retard helps extend the life of the engine as most fuel injected motors today will retard timing and drop the AFR's to 10 to 1 keeping it rich for safety sake, though this is not always adventitious for power.

as long as the engine is not pinging/detonating it will want more advance with rpms. with low compression motors there is more room for error in mix ratios, but with heightened compression especially on motors that are air cooled. it is imperative to always error on the rich side of AFRs for heat sake and detonation sake.

all in all, compression creates a denser fuel charge and thus a more powerful burn. if the engine is not detonating(running correct AFRs for ignition advance and proper fuel grade to prevent pre-ignition) it is completely safe. if its set up wrong, the heat and detonation will destroy the top end parts very quickly as with any motor.

- because of the increased burn power of a higher compression charge, wristpin and connecting rods will take an increased beating and have a shorter life. there is just no way around that.

I actually like the stock cdi advance for power sake now that I have gotten to see it, though I wish it had a stronger spark charge which I believe to be its main downfall.
 
yes many have ignition curves more advanced than mine at high RPM but they are for low compression engines. People buying my CDI are modifying their engines for best power which means higher compression is one of the mods. And with it they don't have to worry about using high octane gas or having pro jetting skills to know for sure that it is jetted just a tad rich.
Yes it is a shame the chinese didn't design their CDI for a strong spark. That is their main downfall. Just improving the spark strength gives a major advantage.
 
Looks to me like the pin slipped sideways, and that was the cause of the scoring.

Are you sure the crack was there before the scoring? It would make more sense that the crack happened after the deepest of the scoring.

Piston still working, pin still scoring, compression still going on, scoring gets deep enough... boom, crack is caused in the thinnest part of the scored wall...
 
to jag: do you make a kit with heightened spark with more aggressive timing curves?

Luka: do you mean the pins in the piston? I don't remember mentioning the crack before anything else. I would have heard it. she all went to crap at once im pretty sure.
 
by aggressive do you mean a more pronounced curve so that it curves downward steeper than the steepest one shown on the graph?
No. counter-productive. I have done extensive testing which is why I settled on the existing range of curves.
 
it is as advanced as it should be.
Maximum input resistance (max advance) is 17 ohms which can lead to detonation with high compression engines which is why I recommend 16 ohms if you have increased your compression.
Standard compression engines can use 17 ohms.
 
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