Iridium plug - idle dropped, stalling issues?
 

Just swapped my plug for a brand new iridium.

Checked the gap, was within spec.

About 1,000 miles in, and now my idle speed seems weird?

Clock reads tick over at 1400 rpm, but it seems lower, almost like it's about to stall.

Twice now, it has stalled on me, on change-up from 1st to 2nd.

Also, if I'm in the low rev range of just between engine braking and accelerating (ie, just enough to keep rolling) it seems very stuttery... like the chain is snagging (but it's not)?

I'm pretty sure the only thing I've done lately is change the plug?

Any thoughts?

Try a different (new?) plug first, preferably a standard copper cored one, to rule out whether or not its the plug (or the whether the iridium is the issue).

Oh, and this might be worth a read too...

http://www.xt660.com/showthread.php?t=21527&highlight=iridium+plug

Chain correct tension, cush drives worn in ?

dodgy plugs
 

I obtained a new NGK iridium plug of ebay and once fitted it into my XTR I noticed the bike did not run as well as it did when running on standard and the fuel consumption increased.
I check up on the NGK web site I found that the plug I got of ebay was a counterfeit, if you have the old box the plug came in, the NGK web site will show what to look out for and how to spot a counterfeit.
Since then I have fitted another iridium plug but this time supplied by local motorcycle shop and its happydays are here again.

ive only ever run my xtx on the iridium plug done 12k miles i think i did 10 mile from showroom to my house and switched out as id had good use of iridium on all my previous enduros

So, here's what I did:

I checked my original plug (fitted by Yamaha at my 6,000 mile service) - it's an NGK CR8E

The cheap iridium plug I got from eBay is a CR7EIX which was clearly not the right one.

The new plug I bought and fitted today is a CR8EIX

Woo! I've got what feels like a brand new bike!
It's smooth, handles low revs really well and roars in all the right places.

Happy now. Thanks everyone.

Please share what Ebay seller you bought these plugs from. Sounds like counterfeit ones. Using a genuine NGK iridium plug shall work just fine. NGK recommends CR7EIX for the XT660.