CR10EK performance vs CR9E

[4Fighter]

The CR10EK's were quite black and sooty. They had been in the motor for close to 4000 kms and it ran flawlessly the whole time. Throttle response was always excellent and rpms were often over 10k off the line and between 10,200 and 10,300 before the clutches got oiled up (PTO leak).

I'm not sure if it's due to the plugs, but my sled is quite a bit slower now. They did install a new belt at the same time (other one was covered in oil) and the rpms are way down and throttle response is too. It's now only pulling about 9000 rpm at lower speeds (WOT) and about 9800 at top speed (100 mph on the speedo after a very long WOT run).

So what did the CR9's look like?

 

[SUPERTUNER]

I have a question for the rest of you about the Yamaha warranty and running CR10EK plugs.

As I mentioned Yamaha gave me a hard time about having them in the sled. Do your dealers/Yamaha have any problem with you running CR10EK plugs in your sled?

I can't fathom a single reason they (Yamaha) would have a problem with 1 heat range colder and a dual electrode tip. I could see it if hotter or incorrect length plugs were installed.

After I was told no warranty with these plugs in the sled I called NGK and spoke to their 3rd tier tech. They said the plugs would work perfectly and couldn't damage the motor. The only issue they said might happen is the plugs getting a little carbon on the tip, possibly leading to misfiring. Their recommendation was to run CR9EK plugs if the CR10EK fouled (which didn't happen).

Have any of you been through this with your dealer?

I would consider getting a new dealer! This is a group of idiots that obviously know very little about internal combustion. Ask them how much they like you as a customer.

 

[ReX]

I would consider getting a new dealer! This is a group of idiots that obviously know very little about internal combustion. Ask them how much they like you as a customer.

The problem wasn't with the dealer - in fact they have been excellent at looking after fixing up my sled very quickly every time there has been a problem.

I've been getting mixed messages about the plugs, but it may be as simple as Yamaha didn't want them in there while trying to diagnose a problem and the way the message was past from person to person to me it got twisted around a little.

I don't know Yamaha's official position on running non-stock plugs (why I posted the question).

 

[SUPERTUNER]

I would consider getting a new dealer! This is a group of idiots that obviously know very little about internal combustion. Ask them how much they like you as a customer.

The problem wasn't with the dealer - in fact they have been excellent at looking after fixing up my sled very quickly every time there has been a problem.

I've been getting mixed messages about the plugs, but it may be as simple as Yamaha didn't want them in there while trying to diagnose a problem and the way the message was past from person to person to me it got twisted around a little.

I don't know Yamaha's official position on running non-stock plugs (why I posted the question).

I have agreat deal of "professional courtesy" but I could understand their thinking if you had a couple heat range hotter plugs! Definately not colder though. I mean no disrespect towards your dealer.

Freddie