MotorBicycleRacing
Well-Known Member
Sick Bike Parts is selling the LIGHTNING HIGH POWER CDI
http://www.sickbikeparts.com/catalo...ucts_id=184&osCsid=d67fucsvsdj57k42k339fnfi95
quality on products
- Thread starter batteway
- Start date
http://www.sickbikeparts.com/catalo...ucts_id=184&osCsid=d67fucsvsdj57k42k339fnfi95
D
Deleted member 12676
Guest
could be a "marginal" spark plug and that your friends CDI had an above average voltage output. That would explain everything. I would try a different plug. Make sure you gap it.
I think these bad CDI's come in waves in some cases, then other times they are just infant mortality from cheap components. I remember in 2009 or so, there apparently was a quantity of dead CDI's and people were coming to us in droves for replacements. We of course had nothing for them at the time.
Key word being "may". We will test these, and if they work and don't cause harm to engines we will sell both. I am weary of using certain aftermarket CDI's in hot hi perf engines. Our desire is not to say one aftermarket CDI is better than the other. We are not a testing house. We desire to offer our customers a choice of aftermarket products whenever possible.
Key word being "may". We will test these, and if they work and don't cause harm to engines we will sell both. I am weary of using certain aftermarket CDI's in hot hi perf engines. Our desire is not to say one aftermarket CDI is better than the other. We are not a testing house. We desire to offer our customers a choice of aftermarket products whenever possible.
Fabian
Well-Known Member
A good part of the problem with CDI's that do work, then fail prematurely, is people either changing a spark plug and forgetting to place the spark plug lead back on, or not correctly pushing the spark plug boot into position.
When you are pedaling like crazy; trying to start the engine, where does all of that energy go if it's not getting to the spark plug, and what is the effect on the ignition system?
When you are pedaling like crazy; trying to start the engine, where does all of that energy go if it's not getting to the spark plug, and what is the effect on the ignition system?
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D
Deleted member 12676
Guest
answer: it jumps back down its own coils seeking circuit "common". Doing so can fry the coils or fry the CDI if the spark jumps back across the primary coil. Same thing came happen with a bad plug too (not just dirty but truly bad so that it won't let the spark jump its gap). So any time the bike won't start you should first pull the plug, hold it to the head fins, and see if you get a spark by pushing the bike or spinning the rear wheel. Weak sparks are really hard to see in broad daylight. Also sparks that you can see will lose strength once the engine is reassembled because high cylinder pressure makes it harder for the spark to jump the gap. Don't ask me why.
keatonx
Member
Maybe more air pressure/density= more non conductive matter the spark has to go through?
Fabian
Well-Known Member
In the case of a spark plug lead not being attached to the spark plug, and when the bike is furiously being pedaled down the street in Lance Armstrong fashion, in an attempt to get the engine started, does the following scenario portray an accurate representation of the current back flow: magnet rotates past the primary magneto coil and induces a rise in potential to around 80 volts. The stored energy is fed to the CDI which pumps it up to a much higher voltage, enabling the energy to jump an air gap at the spark plug electrode.
CDI is pushed to it's limit to produce maximum voltage because it can't jump an infinitely large air gap from a spark plug lead that's not attached to the park plug, thereby leaving the maximum possible voltage rise to back feed to a common ground.
Current now back feeds through the CDI (with maximum potential to jump air gaps to any nearby electrical component) in an attempt to find an earth. If it permanently damages any of the components in the CDI, then the magneto coil is safe, but the CDI is fried.
If the CDI components hold up, or suffer partial damage, current will continue to back feed to the magneto coil. Once it arrives at the magneto coil, it massively raises the potential of the coil and all the current is dumped (through the thin gauge wire) to ground at the solder point on the magneto arms, thereby creating an open circuit condition when the wire melts from excess current flow.
The customer now has an ignition system that fails to operate the spark plug and bitterly complains about Chinese parts and their poor quality. The customer then complains even more loudly that Chinese parts are rubbish when replacing the CDI (which may have survived the torture) and spits the dummy in howls of protest that he has received another bad CDI, even though it's the magneto that's been fried.
In desperation the customer purchases another CDI only to find a "no-spark" condition - customer has a total meltdown and joins a motor bicycle forum to loudly complain about Chinese bicycle engines.
Jaguar, is this an accurate portrayal of what happens when a spark plug lead is not attached to the spark plug or a spark plug that is suffering serious misfire?
I have limited understanding of electrical circuitry and electrical theory.
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