Resistance plugs and non-resistance caps

[peterg]

I’m tuning my bike after a top end rebuild and want fresh plugs on hand. It’s time to replace my caps as well. Since the stock BP7ES plugs are getting harder to find/more expensive I’m looking at using BPR7ES plugs with are readily available/less expensive.

I realize that I’ll need to change the LB05FP caps to LZFH non resistor caps.

Is the BPR7ES plugs/LZFH caps combo a direct replacement for the BP7ES plugs/LB05FP combo? Are there any issues with BP7ES/LZFH combo I should be aware of?

 

[Jim]

Are there any issues with BP7ES/LZFH combo I should be aware of?

I started running that combo last fall (I think) when the non-resistor plugs got hard to find. No problems.... really can't tell any difference. Mines a TCI iggy bike.... '80 SG

 

[peterg]

Thanks Jim. My bike is an 80sg as well but with a pamco ignition. I’ll place the order!

 

[tommytwohands]

I started running that combo last fall (I think) when the non-resistor plugs got hard to find. No problems.... really can't tell any difference. Mines a TCI iggy bike.... '80 SG

Jim,
Are you saying that you run non resistor in both the plug caps and plugs?

 

[willis]

I think that was just a typo if you look at that entire line in the conversation.

"Is the BPR7ES plugs/LZFH caps combo a direct replacement for the BP7ES plugs/LB05FP combo? Are there any issues with BP7ES/LZFH combo I should be aware of?".

It is either one or the other. Either a resistor in the cap or in the plug, but not in both or neither.

 

[Jim]

Jim,
Are you saying that you run non resistor in both the plug caps and plugs?

No, resistor plugs and non-resistor caps.

 

[tommytwohands]

Understood. So is there a problem with running non resistors in both? Short term more than long term

 

[Team Junk]

I'm pretty sure Jim is running resister plugs if I recall correctly.

There has to be resistance in ether the cap or the plug but not both. There must be resistance in one or the other.

On the other hand it seems the downside of no resistance is the guy in traffic next to you can't listen to Buck and Harley on their AM radio until you go away . Might be a good thing in some circles.

I have accidently run resistor plugs and caps on the Gonzo test bench for a while with no bad effect.

 

[Team Junk]

I have also run a GM coil with non resistor caps and BP7ES plugs with no ill effects. Was kinda test to destruction test for the Gonzo which is same box I'm running on the bench now.

 

[tommytwohands]

I have also run a GM coil with non resistor caps and BP7ES plugs with no ill effects. Was kinda test to destruction test for the Gonzo which is same box I'm running on the bench now.

For my plug caps that have no discernible markings besides TD T-134, how would I determine type.
Would the non resistor still have a resistance output or would it be totally flat?

 

[Team Junk]

Should be very low reading on a ohmmeter for non resistor cap. Around 5k for a resistor cap.

 

[ckahleer]

Probably doesn't matter. The stock caps on my bike were 9k each. So, 5k caps and 5k plugs should work fine. And if the only down side to running no resistence is AM radio noise, in the 1950's this may have been a problem.

 

[Team Junk]

Actually either resistor plugs with non-resistor Caps or resistor caps with non resistor plugs

 

[Team Junk]

Having both is not going to hurt anything but it'll cause a weak spark.