Ignition coil resistance

[trialmarc]

Hello folks!

My 2000 Beta Rev3 2T 250 has some electrical problem and there is no spark at the plug. Checking the ignition coil resistance - primary is 0.7ohm and secondary side is 10k ohm which includes 5k ohm plug cap resistor. Searches on the forum seems to indicate that the primary side should be 3ohm; as another data point, my buddy's Evo primary side reads 2.7ohm. So i am assuming the lowered resistance is reducing the voltage across the primary by 75% so that may be reason for no spark. Could someone help by confirming if 3ohm is the right value? Also, is ignition coil specific to 2T/4T or are they the same -- i am guessing they would be the same, but not sure.

I would like to purchase the coil from USA if possible - who should I try? I have not dealt with Beta directly so not sure if they are speedy enough.

Thanks much in advance!

[dan williams]

It’s almost impossible to determine if a coil is good from a dc ohm meter reading. Ignition coils rarely go bad unless they open up. What is common with older Betas is failure of the trigger coil on the ignition stator. There are places that can test and rewind defective stators but they’re in England.

[sirdabalot]

Borrow your friends Beta to eliminate items. 

Edited November 29, 2017 by sirdabalot

[andrewmorpeth]

1 hour ago, sirdabalot said:

Borrow your friends Beta to eliminate items. 

Yes this one works much better than mine im keeping it!

[sirdabalot]

10 hours ago, andrewmorpeth said:

Yes this one works much better than mine im keeping it!

Said a Vertigo owner

[carlos]

The Slovenian made black box's where terrible on the 02 and 03 models, cheap though. I know a guy who used to always carry one with him on a long trail ride they where that bad.

[scifi]

If your ohms readings are accurate, it shows that you have some short circuited turns in the primary of your coil.   Evan if only one turn is shot circuit, it will take all the energy out of the transformer action, so hardly any will pass onto the secondary winding.   I had a brand new ( Indian.) Lucas coil that went faulty after just 200 miles... it also increased the primary current from 3 Amps to about 6 Amps.

 

[trialmarc]

Thanks for the response folks! In case I need to buy a coil here in USA, could you please give me some shops I can try? all I see from my web searches are UK stores or UK sellers on eBay. Thanks much!

[trialmarc]

On 11/28/2017 at 8:14 PM, dan williams said:

It’s almost impossible to determine if a coil is good from a dc ohm meter reading. Ignition coils rarely go bad unless they open up. What is common with older Betas is failure of the trigger coil on the ignition stator.

Thank you Dan. You assessment was accurate. The coil itself is seems to work although I had to get the stator rewound from Steve, and also replace the CDI. Now the bike starts with a single kick!