A question about resistor caps/spark plugs...

OdysseusXS

XS650 padawan
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Good Morning All,

I'm thinking about changing my XS650's plugs from NGK BP7ES's to the iridium versions. I was pleased with the result (although minor) when I did this to my SRX250. Question: I've read just as much as I can find on the forums here, just checking, my bike currently uses the BP7ES plugs, I assume these do not have a resistor built in (always assumed that 'BPR7ES' were the resistor ones), following on from this, this must mean that my caps have resistors in them? Can anyone confirm this for a US released '82 XS 650 Heritage Special? All suggestion gratefully accepted.:confused:
 
If you have original caps, they are probably not marked but be assured, they are the resistor type. You should test them because they do go bad. When they do, the resistance climbs and eventually starts choking off your spark. The originals were rated at a rather odd 9K ohms or so. Best thing to do is replace them with NGK 5K ohm caps. This is just something you do on any old bike, plug wires too.
 
Thanks for the advice guys, I'm going to replace the original caps with the NGK 5k ones, still trying to find a local outlet that sells the solid core spark plug leads/cables. I read somewhere on this site that VW ignition leads for the older stuff are solid core leads which suit the application, can anyone confirm this?
 
The ones I use are stranded copper core. A little tip - make sure you solder the connector that plugs into the coil and fan out the stranded core where you screw into the cap
 
I use the VW Beetle wires on all my bikes, have been for years. A package contains 5 wires, enough to do 2.5 twins. Plug wires are available in two types - resistor and non-resistor. The non-resistor kind are the stranded metal or copper core (like a normal stranded electrical wire) and are what most bikes use. The resistor type are what you are probably referring to as "modern" plug wires. They have added resistance built in like a resistor plug or cap would. You don't want that. As mentioned, the spark plug wire circuit should have one instance of resistance, either the plug or cap, but not multiple ones like plug + cap + wire. That can all add up to too much resistance in the circuit and reduce the spark power. These are the wires I use .....

http://www.ebay.com/itm/EMPI-9411-R...UNE-BUGGY-PARTS-BUG-BEETLE-GHIA-/251430849187
 
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