New plugs needed for plug chops?

[ironsheik]

Hey all. I finally finished up the carb work I started on my '79 850 last year. I realized after everything was back together that the floats were probably too high so last weekend I finally got them right as well as finished replacing all the intake rubber. The bike is running really strong for the first time. It kind of scared my how much faster it got.

Anyways, I'll be synching them later this week but wanted to know if I need new plugs while I dial in the carbs. The plugs were new last Summer but it was running rich so the rings and porcelain are fairly black. Will this burn off or should I start with new, clean plugs? Or do I clean them somehow? One last thing: since my bike is all stock minus a Dyna S, all I should expect to adjust is the air mixture screw and pilot fuel screw, correct?

AND on the VM carbs, turning the air screw OUT means I add more air to the mixture, correct? Leaner? I've searched that one but I see way too many conflicting posts. I assume it's different on CVs or something? Thanks!

Josh

[Guest]

Clean them and use them. I used to be anal about plugs. I just ended up with a bucket of good plugs that I'm using up.

[Steve]

AND on the VM carbs, turning the air screw OUT means I add more air to the mixture, correct? Leaner? I've searched that one but I see way too many conflicting posts. I assume it's different on CVs or something?

You are correct, as long as you remember that the air screws are the ones on the sides of the carbs. The fuel screws are on the bottom. Turning either one of them out adds more; the fuel screw adds more fuel, the air screw adds more air.

.

[49er]

As Chef said, use your existing plugs. If the motor is pulling well through the rev range, start your plug checks at WOT and ona slight gradient. Just do a short practice run before the plug chop run. The heat generated will burn off any carbon that may have been left on the plugs if the jetting was too rich at lower throttle settings.
If the plugs show a black soottie colour, you need to fit a leaner main jet. If the colour is ideal (tan), then you progress back to the needle position 1/2 throttle for your next plug chops. Once that is right, progress to the pilot circuit (idle to 1/4 throttle).
Find some where safe to do these checks.

[ironsheik]

Thanks all. I just needed some clarification that I couldn't find in my searches of previous posts.

Since my bike is completely stock minus the Dyna ignition (stock coils) should I really expect to be changing out the main jets? Are there any other options to leaning out the mixture at WOT? I was kind of hoping to not have to remove the carbs again. I guess I should just get used to, eh?

Josh

[tkent02]

Stock jetting should work, and you can change main jets by removing the float bowls with the carbs still on the bike.
Takes a little dexterity and some magic words.

[49er]

Stock jetting should work, and you can change main jets by removing the float bowls with the carbs still on the bike.
Takes a little dexterity and some magic words.

Yeah, it's like magic. It's all done with mirrors!