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Discussion Starter · #1 ·
I did some routine maintenance this past weekend and changed the plugs. I thought they were just a touch on the light side, but I don't know nothing about nothing when it comes to reading plugs. Here are some pics:







The slightly lighter one is from the front cylinder.

Currently I have a Holeshot slip-on with Dales baseline settings for his pipe. I believe it is 2.5 turns on the A/F mixture, stock jets, his shims under the needles, and a stock filter.

The bike has always run great. I noticed it was getting harder to start, so I decided to do the plugs. It definitely fires up quicker and idles smoother. Should I tweak some settings or based on the pics, just leave the carbs alone.
 

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Slightly rich. Try going to 2 turns out on the front idle mixture screw, 1 3/4 turns out on the rear, instead of 2.5. It's pretty close, don't make any drastic moves. How many miles on those plugs? What is your normal riding regimen (length of average trip, city vs. hwy, hard, reasonable or easy riding)?
 

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Discussion Starter · #3 ·
The majority of my riding is a 25 mile commute each way to work. Unfortunately the commute is entirely on the Interstate so mostly constant 80-90 mph speeds. I try to squeeze in some leisurely riding here and there. Those plugs have right at 7,500 miles on them.

It's been awhile since I pulled the carbs off originally. Are those screws accessible just by pulling the airbox off??

Thanks Andy!!
 

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In that case I stick with my original recommendation. 7,500 miles on stock plugs is definitely close to the limit. The idle mixture screws are hard to get at with the carburetors in place. They are what you are calling the A/F (air/fuel?) screws. There are no air/fuel screws on the SV. When you talk 2 1/2 turns out per Dale's recommendations that's the idle mixture screws.

Unfortunately the idle mixture screws don't have much effect at the speeds you normally run (superslab) so you may need thinner shims under the needles. On the other hand, the plugs could look that way because they were firing inefficiently.

Try adjusting the idle mixture screws, run a week, pull the new plugs and look again. They may be fine. If they are still black look for thinner shims, or try moving the shims to the top of the needle (stock position). It make take a couple of iterations to get it just right.

You really want at least a brownish appearance if not the ideal light tan. If you get to brown I'd quit adjusting stuff.
 

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Discussion Starter · #5 ·
Thanks Andy.
 

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Discussion Starter · #6 ·
I was thinking, would de-snorkeling drastically change my A/F mixture?? I haven't been a big fan of doing it, but thought that might be easier than pulling the carbs again. I'm just concerned it might make the mixture to lean and throw everything out of whack.


I was also thinking of the shims. I don't remember if you use Dale's shims and the stock shims. If you use both to put under the needle the elimination of one might help. I think I only used Dale's and left the stock shims how they came from the factory.
 

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I'm not about to disagree with Andy - and I agree that the plugs probably needed replacing at that mileage - but before you mess with the mixture too much, make sure you are looking at the right bit of the plug....you need to be looking at the colour of the insulator, NOT the body. Also, if the engine had spent some time idling before you pulled the plugs, that insulator will be slightly overlaid with cold deposits, and the plug body itself may be very sooty. It's not necessarily a sign of running rich....just "cool".

Short of clever chaps with loads of technical gauges doing it for you, don't try to set up the A/F mixture by plug colour alone...try to feel how the engine's performing too.
 
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