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Spark plugs after 1 season with closed loop!


About the only place I didn't look.
The local ski doo dealer likely has them in stock. The parts stores will have to order them, still easy to get.
 
Back in the early days of the Apexs Ulmer posted dyno results of using EK plugs. The Apexs consistently picked up a couple HP when using one step colder EK plugs...the reason the dyno recorded a slight HP increase and whether it was sustained HP are definitely debatable.
Yamaha installs the EK plugs in the R6s which is a highly competitive segment of the sport bike market.
Ulmer and Yamaha definitely know more then I do about the benefits of dual electrode EK plugs so since 2007 I have followed their lead and used them in all my Yamaha four stroke sleds both N/A, super charged, and turbo charged including my Tuned Sidewinder.
I have had no performance or starting issues related to ignition or spark plug issues since using EK plugs.
Works for Me!
JM.02c
 
Only thing I’m having a hard time with on these plugs is WHY does Yamaha not use them stock? Not trying to say one or the other is better at all! Anyone have ANY starting issues with these when it’s below zero at night?
 
Only thing I’m having a hard time with on these plugs is WHY does Yamaha not use them stock? Not trying to say one or the other is better at all! Anyone have ANY starting issues with these when it’s below zero at night?
Two words.... Can you guess?
 
Only thing I’m having a hard time with on these plugs is WHY does Yamaha not use them stock? Not trying to say one or the other is better at all! Anyone have ANY starting issues with these when it’s below zero at night?

Once with the Apex I fouled a plug, copper in the NGK 9 heat range. Cold and humid -22C morning, first ride of the season trailer trip. Started as usual but stalled after 1 minute while I was further starting another sled. Can blame it to having shutting it down to early prior night just to unload sled from tailer/valves needing adjustment after 20,000km/old gas. Took me hours to get it started until I found on this site with my phone the hot water on thermostat sensor trick. I knew what would of prevented this that morning.

I quickly changed back to bullet proof iridium plugs afterwards! Never was able to foul these on my old 2 stroke SRX or kids old and new Snoscoot. To me that's worth more than 2HP.

Especially after reading on another thread about the Sidewinder starter automatically cutting off the second the engine starts...I'm happily staying with iridium already on hand to install in my '22.
 
Once with the Apex I fouled a plug, copper in the NGK 9 heat range. Cold and humid -22C morning, first ride of the season trailer trip. Started as usual but stalled after 1 minute while I was further starting another sled. Can blame it to having shutting it down to early prior night just to unload sled from tailer/valves needing adjustment after 20,000km/old gas. Took me hours to get it started until I found on this site with my phone the hot water on thermostat sensor trick. I knew what would of prevented this that morning.

I quickly changed back to bullet proof iridium plugs afterwards! Never was able to foul these on my old 2 stroke SRX or kids old and new Snoscoot. To me that's worth more than 2HP.

Especially after reading on another thread about the Sidewinder starter automatically cutting off the second the engine starts...I'm happily staying with iridium already on hand to install in my '22.

These yamaha 4 stroke sled engines will always foul the plugs if you start them and stop them without allowing them to warm up almost fully.
 
These yamaha 4 stroke sled engines will always foul the plugs if you start them and stop them without allowing them to warm up almost fully.
This is true. I have a few polaris quads and there was a big issue with fouled plugs from not warming them up long enough. My dealer actually had a few do it as they moved them around the yard. I put in Iridiums and have not had an issue. Apparently they carbon foul which although is the same end result but not cleanable like oil fouled ones. They can short them self out when carbon makes a trace between the electrodes. There was a good article on NGK's site.


CAUSES OF CARBON FOULING:

  • Continuous low-speed driving and/or short trips
  • Spark plug heat range too cold
  • Air-fuel mixture too rich
  • Reduced compression and oil usage due to worn piston rings/cylinder walls
  • Over-retarded ignition timing
  • Ignition system deterioration

PRE-DELIVERY FOULING:

Carbon fouling occurs when the spark plug firing end does not reach the self-cleaning temperature of approximately 450°C (842°F). Carbon deposits will begin to burn off from the insulator nose when the self-cleaning temperature is reached. When the heat range is too cold for the engine speed, the firing end temperature will stay below 450°C and carbon deposits will accumulate on the insulator nose. This is called carbon fouling. When enough carbon accumulates, the spark will travel the path of least resistance over the insulator nose to the metal shell instead of jumping across the gap. This usually results in a misfire and further fouling.

If the selected spark plug heat range is too cold, the spark plug may begin to foul when the engine speed is low or when operating in cold conditions with rich air-fuel mixtures. In some cases, the insulator nose can usually be cleaned by operating the engine at higher speeds in order to reach the self-cleaning temperature. If the spark plug has completely fouled, and the engine will not operate correctly, the spark plug may need to be replaced and the fouling cause identified.
 


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