I have 3 coils off 1980 xs650s. The service manual calls for a 2.5 ohm primary. All 3 coils i have measure around 3.5 ohm at 80 degrees F. Are these coils dying of old age? One bike runs well the other is hard to start after riding and the 3ed coil is a spare.
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bad coils ?
- Thread starter bill932
- Start date
I checked the manuals at "thexscafedotcom" site and they give 2.5 Ohm for the SG through to the SK. I did see 3.9 Ohm listed for the SF.
Is the Part Number printed the same on all 3 coils you have?
Is the Part Number printed the same on all 3 coils you have?
Did you zero your meter?
You still need to zero a meter, even if it is digital.
Set it to it's lowest scale and touch the leads together. Make note of what it reads and subtract that from your coil readings. For instance, say the meter shows exactly 1Ω with the leads shorted, you'll subtract that from your coil measurement. So If you read 3.5Ω, subtracting the 1Ω zero reading, your actual coil resistance would be 2.5Ω.
If you do end up needing a new coil, or just want to replace it, a nice cheap option is a used Honda MP08 coil from eBay. These have about a 3 ohm resistance but work just fine with the factory TCI or a Pamco. The nice thing about them is you can change the plug wires. Here's a write-up I did with all the info you'll need .....
https://www.xs650.com/threads/honda-mp08-coil.55408/
https://www.xs650.com/threads/honda-mp08-coil.55408/
I did touch the leads together and subtracted that figure from the coil reading. My coils ohmed out at 2.5ohm I was considering the mp08s but i guess I'm good. Thanks JIM & 5 twins. An old dog can learn new tricks.
Nice one Jim...
