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Discussion Starter #1
Ever since I swapped my old copper plugs for shiny new iridiums, the bike has been having trouble at part-throttle. Nothing serious, just annoying. It isn't as smooth as it used to be, stumbles a bit now at 3500-4000 rpms. The idle is a bit less reliable as well, it sounds irregular and varies from 1100-1400 rpms.

From 50% to wide-open throttle she's a freakin' monster! Still screamin to redline.

I already checked the TB sync and TPS, and double checked all the vacuum lines and plug wire connections. All appears to be golden.

My question is, did anyone else have to adjust their fuel map after changing to iridiums? Could it be running leaner or richer? I've got a Yosh box and I'm pretty sure I had it set at +5+5+10 at 10:30, but I can't remember. Any recommendations?

Oh, and I'm getting 50-60 MPG lately. The best I ever got before the new plugs was 45 MPG.
 

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Are the new plugs rated ok? On 2 strokes a 'warmer' plug can make a lot of difference on how it runs!
 

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No remap should be necessary for Iridiums!

Greetings
Rufer
 

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Technically iridiums should be able to light fuel more easily.
If in the midrange you had set the mixture in a particular way and say the fuel was being burnt more effectively then it is indeed possible that a remap may be necessary.

iridums require less energy to spark so the spark will occur earlier than with a std plug. strange but true the coil is saturated with power and it is let loose on the plug. the current builds up on the centre electrode until it it high enough to bridge the gap. if the plug requires less energy such as an irium the spark will occur sooner in effect slightly advancing the timing . its miniscule but both things could well be reason to check the map to ensure it is still optimal
 

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Discussion Starter #6
Thanks for the input. I think I'll try that pos mod before doing anything else, I probably need to do it anyways.
 

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Technically iridiums should be able to light fuel more easily.
If in the midrange you had set the mixture in a particular way and say the fuel was being burnt more effectively then it is indeed possible that a remap may be necessary.
Would that be because of a better spark and ignition, or a closer to ideal timing of the ignition? Does a shot spark plug take longer to spark?
 

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Discussion Starter #8
Are the new plugs rated ok? On 2 strokes a 'warmer' plug can make a lot of difference on how it runs!
Plugs are the same heat range as the old ones, CR9EIX instead of CR9EK
 
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