JoeH
Groundie
Posts: 2 
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Post by JoeH on Dec 22, 2022 14:12:51 GMT -5
Will a Homelite 925 flywheel with a 3 piece ignition work with the 1 piece ignition coil?
The 3 piece flywheel has magnets on the inside to trip the module. Best i can tell there are no magnets on the inside of the 1 piece flywheel so it seems the question is - will the 3 piece outside magnets work with the 1 piececoil?
I know homelite shows a different part number for the 1 piece flywheel but i was wondering if anyone has tried using the 3 piece flywheel with the 1 piece ignition? is the timing or location of the magnets different?
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Post by ettrick on Dec 30, 2022 21:57:12 GMT -5
Is there something wrong with your 3 piece system? Why not repair that instead?
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Post by lesorubcheek on Dec 31, 2022 23:25:47 GMT -5
That's a good question. Haven't looked in a while, but I think the one piece flywheels have a similar boss where the magnets are on the 3 piece underneath, but may be wrong. Never looked if the outer magnets are timed and spaced the same with the flywheel key. The other thing is the magnets polarity needs to be the same. Just a guess, but I'd bet that something is different between the two since the conversion kit to single piece ignition includes the backing plate, module and flywheel. You'd think for a conversion kit if the flywheels from the 3 piece could be used, it wouldn't be included. Again, just a guess, really have to get the two side by side to know for sure.
Dan
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JoeH
Groundie
Posts: 2
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Post by JoeH on Jan 3, 2023 13:40:04 GMT -5
Thanks Guys,
Got a big tree coming down in the spring. Too big for my Stihl 280 (55cc) to cut up. Decided to get my old 925 running (no spark) rather than buy a new 70cc chinese clone. Replaced ignition, bad wiring, and oil seal, compartment was packed with oily sawdust. After repair and cleanup it starts and runs great with a 30" bar. Totally amazed to easily find all the NOS parts I needed.
After i got the work done i found out it could have been converted to the simple one piece ignition and was curious about what had to be done.
joe
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Post by chyfarm on Mar 19, 2023 22:30:09 GMT -5
Seems this is related to US patent #3554179 "Antireverse trigger for an ignition system" invented by Bob O. Burson.
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Post by chyfarm on Apr 3, 2023 21:08:17 GMT -5
Here showing the patent number on the flywheel; Attachments:
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Post by chyfarm on Apr 3, 2023 21:09:27 GMT -5
And pics here are pages from this patent filed in 1971; Attachments:
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Post by chyfarm on Apr 3, 2023 21:11:27 GMT -5
Figur4 and 5 tell how this construction moves firing timings before TDC; Attachments:
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