A hair Rich?

My bike seems to runs flawless. I run in temperatures from about 60 to 90 degree at elevations from about 2000 to 4500ft. My main is a 168 and pilot 48 fuel screw at 2. My problem is when I pull the plug it appears to be running a hair rich. Not rich enough to be fowling but rich still the same. For fear of messing with jetting because it seems to run so good from the saddle, what is everyones thoughts on running a hotter plug to remedy this? The bike calls for a CR8E/NGK. Do they make a CR7E (slightly hotter)? And what are everyones opinion on doing this, is this this just a bad idea?

check the stick thread above for your temp and altitude, Indy will get you very close to perfect.

I'd check the clip position on the needle ... if it is on the 4th notch from the top i would try it on the 3rd notch for 5 minutes of bush-bashing to feel the difference (and check the plug color) - personally i don't like running a hotter plug unless it is a last resort.

Try to keep the chamber at the correct temperature by fine-tuning the jetting.

If you are checking the plug color after the bike has been idling for a minute then you are really only checking the pilot/fuel screw mixture - a throttle chop is needed to check the needle - and another to check the main.

You could always turn the fuel screw in 1/4 turn ?

My bike seems to runs flawless. I run in temperatures from about 60 to 90 degree at elevations from about 2000 to 4500ft. My main is a 168 and pilot 48 fuel screw at 2. My problem is when I pull the plug it appears to be running a hair rich. Not rich enough to be fowling but rich still the same. For fear of messing with jetting because it seems to run so good from the saddle, what is everyones thoughts on running a hotter plug to remedy this? The bike calls for a CR8E/NGK. Do they make a CR7E (slightly hotter)? And what are everyones opinion on doing this, is this this just a bad idea?

That is simply because of ACV. Dont touch your jetting, it will be fine.

Unless you run leaded fuel, don't bother with plug checks.

That is simply because of ACV. Dont touch your jetting, it will be fine.

Unless you run leaded fuel, don't bother with plug checks.

Maybe I'm dumb but what is ACV?

Do you have a manual?? Air Cut Valve (ACV)

If so you can check how the ACV works - also look in www.thumperfaq.com for a detailed answer.

In Short:

It closes off air drawn through the intake bell (Via MAJ) which is emulsifies the fuel through the pilot jet on shut throttle seetings; richening the mixture on decel which helps prevent back fire (or POP) on decel.

The ACV can be disabled closed or open to get rid of it cutting in and out. There are pros and cons to each method of ACV mod. Blocking it closed (as on decel) requires lowering the pilot to YZ spec (#42?) and changing out the MAJ also to YZ spec- not sure on the numbers for these!

I deactivated mine in the normal position (open) to stop the richer fuel mixture on decel. That allowed better fine tuning with the fuel screw and prevented some surge/run-on at lower (shut) throttle settings (dont confuse surge with TPS!!). The result was a little more POP but you can dial that out by 1/8 to 1/4 out on the fuel screw. Personally, I left the pop! :ride: as the extra fuel was a bit rich otherwise...

My .02 worth :thumbsup:

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