Magneto update

Fabian

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Sep 8, 2009
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My engine supplier has just got his hands on a 66cc sample engine for me to test; using the new magneto design.
If i find that it's reliable and operates with similar efficiency as the current magneto/coil design, he will order a container shipment.

The engine is similar if not identical to a Grubee Skyhawk "SuperRat", in that it uses an identical 47mm bore, though the stroke is 38mm instead of the "SuperRat" 40mm stroke, which makes the "Rat" engine 69cc; an extra 3cc over the engine i have received.

Here is the engine on the Grubee webpage: http://www.grubeeinc.com/USA/SkyHawk%20Gt5-SR%20SuperRat.html

Having said that, the normal 70cc engines he sells use a 40mm stroke, so if the crankshafts are the same between the new engine design and the old engine design, it would seen logical that the longer stroke crankshaft could be retrofitted into the new engine design.

Thankfully this new engine design is now being sold in the mass market; making magneto parts readily available; Gasbike being one of the suppliers: http://www.gasbike.net/grubee-skyhawk-gt5-sr-66cc-80cc-slant-head-standard-finish-bike-motor-kit.html



The next question directed at my bicycle engine kit supplier was of the ignition advance curve: was it a 4-stroke advance curve like the commonly available magneto/CDI or a proper 2-stroke ignition advance curve.
It turned out that he was unable to give me an answer so i had to do some more digging, hence i went to town on Google.

Doing some research revealed that this particular integrated magneto system is used on the 2-stroke 3WF18 misting blower,

http://www.delshine-garden.com/pid12366891/3WF18-9+(20L)+131kw+Agricultural+Power+Sprayer.htm

http://www.alibaba.com/product-detail/coil-and-rotor-for-WFB-18_307572702.html


and


the company that manufacturers the integrated magneto is Zhongci, which lists the part number as ZC6002, so spare parts supply is not a problem,

http://www.cnzhongci.com/ENGLISH/productshow.asp?id=1198




so, without further ado, here are the photos,
























A side note is that a small flywheel puller will be needed to remove this type of magnet from the crankshaft:
$_12.JPG





 
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Fabian

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With the altered design, you no longer need a Jaguar CDI; if compression ratio is kept within reasonable limits, considering the circuit design should be optimised for 2-stroke operation; as it's used in a 2-stroke misting-blower.
If it really does use an ignition curve properly optimised for 2-stroke operation is another discussion in itself, and will require testing by someone who has the skills and equipment to create a graph of the ignition curve.

The benefit of the Jaguar CDI is that of ignition curve adjustability, with the V2.0 adding an automatic correction parameter for ambient air temperature variation.

The integrated magneto/CDI/coil system will not operate a Jaguar CDI, unless a specific magneto coil is designed for the new circular magnet.


A significant benefit of the new design is simplification of the wiring system, by use of an all-in-one magneto/CDI/coil which is typical of the ignition systems found in chainsaws.
Another benefit is that of trouble shooting an intermittent ignition problem, because if you suspect an ignition problem, it's so much easier (after you've replaced the spark plug) to throw the integrated magneto/CDI/coil/spark plug lead over your shoulder and (by only unscrewing two screws) replace it with one single item.

This has many positives in that only a single electrical spare part is needed in your bicycle tool box, when touring on the road, and it requires no more than 60 seconds to replace the entire electrical system; which also reduces clutter as no electrical parts are attached to the bicycle frame.
 
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velzie

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Oct 27, 2013
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I am interested to see what it's timing curve looks like, and its quality of spark. Hopefully the misting blower isn't timed like our engines but more like proper 2-strokes that use this design. I am not a fan of packaging separate units into one larger, combined unit. Might make replacement more expensive. Also, if the unit isn't timed well, or if you would like something more adjustable, it might make an improved unit more expensive.
 
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Fabian

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I am not a fan of packaging separate units into one larger, combined unit. Might make replacement more expensive.
Ironically it could make the product cheaper considering the coil and magneto coil and the ignition coil are all contained in one "sealed" unit. Typically, sealed units seem to be more resistant to vibration and moisture ingress.
My experience with Chinese bicycle engines and their associated electronics, in comparison to the electrical reliability of chainsaw style ignitions has proven integrated systems to be exceptionally reliable.

If the ignition curve on the new integrated magneto/CDI/coil/spark plug lead proves to be suitable for conventional operation with an after market medium compression billet cylinder head, then it's goodbye to the Jaguar CDI, which was only needed because the standard CDI used a 4-stroke ignition curve; hammering out the big end connecting rod bearing.

if you would like something more adjustable, it might make an improved unit more expensive.
If you want something adjustable, then you always have the option of purchasing an engine using the current ignition system layout, thereby allowing use of the Jaguar CDI.
It so happens that my bike has always been fitted with a Jaguar CDI and coil (after my string of engine failures using a standard CDI) and has served me well over time; with equal electrical reliability as compared to the standard CDI/coil combo, but giving "all" of my engines a dramatic improvement in connecting rod bearing life; massively increasing engine reliability.

however,

if the new integrated ignition proves to be reliable and proves to be just as kind on the connecting rod bearings, the new magneto system will become my preferred ignition system.

Time will tell, but unfortunately i won't be installing the engine until my current engine starts to give up the ghost, which ironically i am hoping for (because it uses the old style caged needle roller big end connecting rod bearing), but the way the engine is running, it's not going to happen any time soon.
 
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jaguar

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Nov 25, 2010
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I think it is an improved version of the old CDI/coil but with the same ignition curve which means you are asking for trouble if you increase the compression or increase the peak RPM. Blowers probably don't rev higher than 5K anyway.
If I were you Fabian I would swap engines just out of curiosity if nothing more.
 

Fabian

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Sep 8, 2009
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Don't you all worry your little beating hearts because "i will" be changing my current engine (when it eventually fails) to the new engine with updated magneto design, upon which "i will" then beat it to death; seeing how it holds up under the torturous conditions experienced on my touring journeys.
 
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