Spark plug ?

chrispyduck

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I use iridium spark plugs in all my bikes with success so want to install same to my newly acquired XS650B. What is the correct NGK iridium plug?? I have read on here that some opt for hotter grade ??
Many thanks
Chris
 
Yamaha specced the #8 heat range NGK plug for the early models. They updated that recommendation to the one step hotter #7 NGK on later models. It can be fitted to all models and it is accepted practice to do so. Also, the early spec was for a regular "B" type plug while the later spec, along with the heat range change, also changed to the "BP" (projected tip) type plug. Again, this can also be fitted to all models. I would use the 7's for normal riding, only switching to 8's if I was going to take a trip and be running sustained high speeds and RPMs on the highway. The 7's will give a cleaner burn and better plug color (not as dark) in daily, around town riding.

Something else I'll mention is those Iridium plugs are the resistor type. If you're going to use them, you should change your resistor plug caps to non-resistor types. You only want one instance of resistance in each plug line, plug, cap or wire, not multiple ones. That can add up to too much resistance and start choking off your spark.
 
Spark plug confusion:

Always ran NGK plugs in all the bikes thru the years. Lily, my VStar 250, shipped with NGK C6HSAs.
Ran NGK BP7ES plugs in our XS650s -- found three cleaning up the garage. THREE? really? Brand new, all in different style boxes. None for Lily. Garage must ahve eatten those. Anyway thought as long as I had to get plugs I'd to upgrade to Iridium for both.

No NGKs in stock locally on NGKs for either bike. Went to order them, but the conversion numbers are not making sense.
BP7ES is showing me NGK BPR7EIX for Iridium number, and C6HSA converts to NGK CR6HIX.
I think the IX is Iridium on both, but ignoring that, is the R for Resistor? If so I'll steer clear of those.
 
Yes, I'm pretty sure the "R" means "Resistor". They seem to be more and more the "norm" these days but we don't want them. If you must run them then it's recommended you change your resistor plug cap to a non-resistor type. One of the nicest I've found is the NGK LZFH, but these are getting hard to find as well .....

NGK LZFH-New.jpg
 
Yes, I'm pretty sure the "R" means "Resistor". They seem to be more and more the "norm" these days but we don't want them. If you must run them then it's recommended you change your resistor plug cap to a non-resistor type. One of the nicest I've found is the NGK LZFH, but these are getting hard to find as well .....

View attachment 328150
Thanks for the explanation. Thinking I need to replace the plug wires anyway -- they appear to be original -- but I hadn't investigated that yet.
 
Well, if your coil is an original, you can't replace the plug wires, they're molded in. About the best you can do is snip off 1/4" to 1/2" from the end to get to some "fresh" wire. I like to go one step further before installing the plug cap. I strip about 1/8" of the insulation off and fan the wire strands out in a radial pattern like so .....

Plug Wire End.jpg


This insures I hit some actual wire when I screw the cap on. I also like to put a little dielectric grease on the end of the wire and on the cap where the rubber boots slide on to help seal and waterproof it ......

PlugCapGrease.jpg
 
I wanted to replace the plug wires on my '83 so I changed coils. I had been wanting to try a Honda MP08 coil after reading about them here on the forum. They are said to be very dependable and you can also get them quite cheap off eBay. This was the perfect opportunity for me to try one .....

https://www.xs650.com/threads/honda-mp08-coil.55408/

Compared.jpg


HondaMP08Installed2.jpg
 
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Well, if your coil is an original, you can't replace the plug wires, they're molded in. About the best you can do is snip off 1/4" to 1/2" from the end to get to some "fresh" wire. I like to go one step further before installing the plug cap. I strip about 1/8" of the insulation off and fan the wire strands out in a radial pattern like so .....

View attachment 328267

This insures I hit some actual wire when I screw the cap on. I also like to put a little dielectric grease on the end of the wire and on the cap where the rubber boots slide on to help seal and waterproof it ......

View attachment 328270
I've seen the wires pictured like this before but not the explanation of how. Like this plan!
I wanted to replace the plug wires on my '83 so I changed coils. I had been wanting to try a Honda MP08 coil after reading about them here on the forum. They are said to be very dependable and you can also get them quite cheap off eBay. This was the perfect opportunity for me to try one .....

https://www.xs650.com/threads/honda-mp08-coil.55408/

View attachment 328303

View attachment 328304

And I like this idea, too. Possibly both at the same time with new plug caps. Thanks so much! Time to go shopping! :D
 
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