RD350 Ignition Coil Resistance Values

[Pravin]

Hi All ,

I  had got pair of Ignition coils for my RD350 Points conversion !

The resistance am getting is 4.5 ohm between the leads and 8.3k between the PIN(where thr HT cable goes) and the leads..

Are these values correct ? if not what are correct and tolerable values ?

Cheers
Pravin

[m in sc]

if its 3-5 ohm + to - should be ok. I don't know the secondary off the top of my head. just make sure the wire is zero and the plug cap is no more than 5

[Pravin]

Thanks SC

Currently am using NGK 5K Resistive cap but am going to toss them and use Non Resistive ones ..

AS of now am measuring directly on the PIN and the +  or  - ends ..around 8.3 8.4 K its coming

Cheers,
Pravin

[m in sc]

that should be fine.

however, if they are old original ones id never trust them 40+ yrs out..

[Pravin]

Yes they are old ones 73 74 I guess as I got them off ebay..

Will only come to know once installed I guess :(

Next can be the EMGO or after market coils from HVC ? Any reviews ? just in case if I want to be thinking that direction ?

Cheers,
Pravin

[m in sc]

the replacements are great. skip the round body emgos go with direct replacements if you can. https://hvccycle.net/yamaha-ignition-coil-254-82310-60-00-2102-0301/

john at economy sells them as well:

https://www.economycycle.com/shop/yamaha-rd250350400r5ds6ds7-parts/electrical-ignitions-lighting/ignition/yamaha-rd250350400-direct-replacement-ignition-coil-23-99/

but any 3-5 ohm single lead coil will work. ;)   as do early sv650 coils. yes, they are the correct rating

https://www.ebay.com/itm/313238059336?fits=Make%3ASuzuki&hash=item48ee717948:g:T5AAAOSwNIZfc2Cu

[Pravin]

Thanks SC ,
Let me install the ones I have and observe if they are failing at any range of rpm or overheating even after battery is at the required voltage etc and then will decide ....

Thanks for the information ! I know what to look for now 😃

Cheers
Pravin

[Clem710]

The problem with the old ones is that they seem to like to slowly fail and make you think you have a carburetion, fuel delivery or points problem.  Which, come to think of it, one side of the 400 is running not quite as good as the other even though the plugs look identical....hmm

[pidjones]

Re: 5 k resistive caps. Probably best move to remove them because it gives better supply of plugs. Non-resistor plugs are getting hard to find. Most NGK caps with resistors can be disassembled and resistor replaced with solid wire (like bare #10 house wire) or a short section of copper tubing. Then you can use resistor plugs. BTW, do not replace the wires with automotive carbon core wires! Only use solid or stranded core wire. Sometimes hard to find. My local O'Reilly will order in a 100' spool, cut off what I want, and send the rest back. The 5k resistance in one of; plug, cap, or wire is needed to reduce radio interference (also reduces electronic ignition problems). Even old systems can fire the plugs just fine with a single 5k resistance. They have problems with two such as using resistor plugs and resistor caps.

[AAAltered]

Like Clem said.  It's tempting to save a few bucks and use "good" used coils. 

My experience with that ended with a box full of questionable coils and two brand new non-Emgo units that solved lots of problems.