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Post by carasdad on Dec 21, 2013 11:08:53 GMT -5
After analysis and testing many 'performance' CDI's with an inductive timing light. I have seen that they must be a hoax. Ok let's look at this. Our ignition systems are controlled by a magnet and a pickup coil. The ignition CANNOT fire UNTIL the magnet passes under the pickup coil. The system itself is fixed and non advancing..unlike like a cars electronic or vacuum advance for the Distributor. The CDI can ONLY fire once it gets a signal...which again comes from the pickup position. Slotting the stator on 2T's and moving the pickup by elongating its mounting holes on a 4T will show an advance with a timing light as I have found. But again..the timing may be advanced but it is still fixed. So hopefully somebody can explain to me how a CDI can fire in an advanced timing curve mode..long before the pickup signals it to fire??. It is no wonder that folks with stock to modified engines see no difference or gain from a 'performance' CDI. Input on this would be greatly appreciated AND help folks..so they don't waste money on a gimmick type part. Lastly..when I was not concerned with tinkering with timing..3-5 degree 2T offset flywheel woodruff keys were everywhere..now that I want to mess with one..I can't find them. Anybody know of a resource for them? Thanks, Glenn
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Post by phssthpok on Dec 21, 2013 15:11:19 GMT -5
In such a situation it is not beyond the realm of possibility for the engineers to incorporate a permanent physical advance in the timing of the magnet passing under the pick-up, and having the CDI incorporate an electronic 'delay' in sending spark signal out at lower RPM. Conversely, the CDI would, at higher RPM, reduce the delay in passing along the signal resulting, in effect, in 'advanced' timing (read: 'not delayed') over lower RPM.
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Post by tvnacman on Dec 21, 2013 15:26:21 GMT -5
I hope I don't blow my engine removing the fan cover to get it on video .
John
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Post by alleyoop on Dec 21, 2013 15:39:33 GMT -5
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Post by phssthpok on Dec 21, 2013 16:06:50 GMT -5
I hope I don't blow my engine removing the fan cover to get it on video . John I presume you mean to remove the fan assembly in order to film the timing marks while the engine is running and changing RPM? If you have an electric leaf blower (or reversible vacuum cleaner) you could direct the output over the engine... some air movement is really all you need and either arrangement should provide more than enough. |
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Post by carasdad on Dec 21, 2013 16:52:27 GMT -5
Alley..tx..been wanting to play with one of those. But typical fate being..when ya don't want sumpin..they got 5 million online..BUT the day ya go looking for one to tinker with..they disappear.. More Chinese marketing tactics I think.. You know..create your own supply and demand..lol..  ....  |
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Post by carasdad on Dec 21, 2013 17:01:57 GMT -5
In such a situation it is not beyond the realm of possibility for the engineers to incorporate a permanent physical advance in the timing of the magnet passing under the pick-up, and having the CDI incorporate an electronic 'delay' in sending spark signal out at lower RPM. Conversely, the CDI would, at higher RPM, reduce the delay in passing along the signal resulting, in effect, in 'advanced' timing (read: 'not delayed') over lower RPM. That I think may be plausible..since unlike a car..the pickup nor magnet are able to rotate to a new position to allow that type of advance..  tvnacman..I did have one that seemed to advance..that was the Casoli brand. But each rev was not consistent in where its firing point was illuminated by the inductive timing light.. i.e. at 4k then 6k each rev..it appeared in a different spot. So i had to check my flywheel nut and woodruff key to make sure the flywheel was not loose. But again..the advance?? was never consistent..more like a fluke with my timing light maybe.. |
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Post by tvnacman on Dec 21, 2013 17:10:59 GMT -5
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Post by JerryScript on Dec 21, 2013 22:05:55 GMT -5
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Post by carasdad on Dec 21, 2013 22:37:56 GMT -5
Just curious as to how this all is just beating a dead horse? When all of us are uncertain.. It means you already have the answer..so please share it with us? Thanks..looking forward to an answer on how this works and I am sure others will benefit from the input...  Glenn |
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Post by JerryScript on Dec 21, 2013 22:50:32 GMT -5
Ooops, I meant to hit the smiley right below that one, this one  Sorry, maybe I should stay away from those smileys! I have not used a timing light on my scooter, but I do have the advancing angle CDI recommended by alleyoop and sold by tvnacman, and I can tell you it did help with some issues I was having. I really have no idea where in my garbage dump of a garage my timing light might be, but if I can dig it out, I will do a test and post the resulting video. |
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Post by urbanmadness on Dec 21, 2013 23:02:54 GMT -5
Consider this... for advance timing, you could always delay the spark until the next revolution. So you are using the signal from the current revolution for the next, netting you an ignition advance. You could then do some more electronic wizardry to get the advance curve, based on RPM. If you could do a mass airflow sensor and or a vacuum sensor, you could also base the ignition timing on load as well as RPM.
I'm not saying this is how they work, but if I was going to design one, that is how I would do it with a fixed CDI signal.
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Post by skuttadawg on Dec 21, 2013 23:06:33 GMT -5
here is the video
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Post by rockynv on Dec 21, 2013 23:18:15 GMT -5
Don't know about them being a hoax. Did improve cold weather starting, idle and throttle responce on my Lance when I put Scrappy's DC non-adjustable CDI and High Output Coil set in. Had to replace the variator and some bad bearings to really take advantage of it. It still was a stock 150cc GY6 afterwards but a little more of a solid runner.
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Post by tvnacman on Dec 22, 2013 10:23:49 GMT -5
Don't know about them being a hoax. Did improve cold weather starting, idle and throttle responce on my Lance when I put Scrappy's DC non-adjustable CDI and High Output Coil set in. Had to replace the variator and some bad bearings to really take advantage of it. It still was a stock 150cc GY6 afterwards but a little more of a solid runner. I would disagree if you have a coil problem you have a coil problem , if your having trouble getting it to start with normal cranking , then is air fuel mix . If you had bearing problems you had bearing problems . We are talking about bas timing on start up , then advance timing at rpms above idle . Clutch springs will have no effect on start up unless the clutch is dragging . If the engine starts and runs a performance coil will not yield improvement in start up you only need minimal spark to ignite the mix , when and where in time you ignite is where the gain is . John |
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..BAD TO THE BONE..
