[jrsyamaha]

Hey, CD A buddy of mine told me about running Autolite plugs in my bike. Is that possible? If so, which ones would work for a '00 RS Tour Classic with; Intake , Exhaust, and Carb Mods done? I asked a mechanic and he told me " No, due to the resistance is all wrong, they are for cars and trucks, not Motorcycles". Who is right?
By-the-Way, The info on what to do with my Jets worked great. My mileage is back up, and seems to have a lot less studder in the mountains. Thanks to everyone for the Help. This site is great for the True Info from poeple who know what their talking about!!!!!!!!!!!!!!!!!!!!!!

[CD]

The base plug for late model XL and all TC88 engines is the RA8HC Champion. Any plug matching that will work. For example, Autolite AU-4164, Accel Y2418P, NGK DCPR7EIX ETC. Heck the EVO uses a truck plug the RN12YC.

Plugs are either resistor or non resistor. Electronic ignitions must use either a resistor plug or in some cases a resistor is used in the cap and a non resistor plug is used instead.
When resistor plugs first started being used, the R in the number like RN12YC indicated that it was a Champion resistor version of the N12YC plug. Now, there are so many part numbers and you need a cross reference to get it right.

Hope you were wearing waders when that mechanic was slinging the crap.

[CD]

Sleepy pointed out that I missed the RS part...Sorry about that.

Now...wanna hear a bit of freaky coincedence? The RA8HC Champion is the same plug used in the RS according to
http://www.championsparkplugs.com/re...D=16329&mfid=2

So, all of the above actually did apply.....Hmm, I'm going to the casino tonight!

[jrsyamaha]

CD or Sleepy, Which one would you perfer to have in your bike for the best peformance? They can't be created equal persay.

[bikerjim1]

I, myself, have been using an Autolite for years in my 94 Dyna, and to be honest, get a WHOLE lot longer life from them than the "Champions" Harley churns out for their choice of plugs. Save yourself a lot of $'s and dissappointment, and go to the auto counter @ Walmart and look up the plug that fits your scoot.

[Sleepy]

I don't know which one is best..I've used Champions on the Harley..never really had a problem with them. I use NGK for the RZ 350. SK, who is in Street Vibrations right now , has a Royal Star, and has forgotten more than I'll ever know about them. Your motor's been modified so I'd get in touch with someone who knows the motor..Baron's comes to mind and they should be able to tell you which plug would work best for you.

[CD]

I run about whatever is in reach when I am doing service on the RK. I had to get it sniffed the other day for the first, last and only time. The Champion plugs have been in there since last August at least. The dang thing hardly registered on the test equipment and that is with old plugs and a tweaked idle. Oh yeah, I am getting nearly 50 MPG with this combo unless I am way in it.

Now, when we drag raced, we used Champion RC12YC for one or two runs and always new plugs for eliminations. I don't remember having any issues with the them but there are those that say they have....

If you are properly jetted and there are no internal problems the plug will burn clean and will only need to be replaced when worn or a random failure occurs. There are precious metal plugs that burn cleaner and the electrodes last longer so plug changes are less frequent of course.
If spark plugs area concern go to a parts store and cross reference some different brands and try them out. Find the ones that work the best for you and stick with them.

[Breeze]

Whether you need resistor plugs or not, the big kicker is heat range. When you look at a cross reference table you are looking at equivalent heat ranges. Technically any equivalent heat range should work as well as another. Different brands of recommended plugs may have broader or narrower heat ranges than what you were using and your engine may run different (better or worse). Personally I've never had any issues with Champion or Autolite but never had luck with AC. Someone else may swear by ACs.

The rule of thumb used to be, use the coldest plug that won't foul if you're on the highway a lot. I don't know how this holds up today with unleaded gas... OK so I have been around a few years.

[jrsyamaha]

Originally Posted by jrsyamaha

Hey, CD A buddy of mine told me about running Autolite plugs in my bike. Is that possible? If so, which ones would work for a '00 RS Tour Classic with; Intake , Exhaust, and Carb Mods done? I asked a mechanic and he told me " No, due to the resistance is all wrong, they are for cars and trucks, not Motorcycles". Who is right?
By-the-Way, The info on what to do with my Jets worked great. My mileage is back up, and seems to have a lot less studder in the mountains. Thanks to everyone for the Help. This site is great for the True Info from poeple who know what their talking about!!!!!!!!!!!!!!!!!!!!!!

Live Today as it were your Last

[Breeze]

Since you reposted the original message, I suppose you want someone to read the chart and tell you which plug to use... recommended plug by Autolite is the 4164 or MP4164 for a stock engine. The mods you mentioned won't likely cause a big deal of difference in plug requirements. If you have increased compression, that is another story all together. If you are set on trying the Autolites, try the recommended plugs first. If you blister them and carb adjustments can't correct it (assuming ignition timing is correct), try a colder plug. If you have problems fouling, go to a hotter plug. American plugs are hotter as the number goes up (unless they changed this when I wasn't looking) and Japanese plugs go colder with higher number (go figure).