Stupid spark plug color question... : V-Twin Forum: Harley Davidson Forums

x1rider · 09-02-2009, 04:56 PM

my friend and bike mechanic passed away last summer and I'm pretty much left on my own trying to fool around with my FatBoy (Zippers 120" kit for Twin Cam 88). After changing the pipes I noticed the rear peg and swingarm were sooty with idling and low throttle opening. I tried going down in pilot jet size (twin Mikuni HSR42, individual runners manifold setup) and went for a little ride. I pulled the plugs and they were white from being too lean.
My question is can I re-use the same plugs after going up in jet size or are they going to stay white no matter what (do I have to use new plugs)?

Thanks a lot for any help or information and my apologies if it's a stupid question.

Waffen · 09-02-2009, 05:10 PM

You can use the same plugs. However, if you want to get a good reading with the new jet size use new plugs.

W

atrick · 09-02-2009, 05:53 PM

If you got access to a glass bead blaster, just clean them that way and reuse, just like a new plug

claydbal · 09-02-2009, 06:00 PM

with todays fuel, dont be so sure you are lean with white plugs. things have changed.

wfolarry · 09-02-2009, 06:07 PM

Quote:

Originally Posted by claydbal

with todays fuel, dont be so sure you are lean with white plugs. things have changed.

X2. plugs don't color like they did in the old days.

Mohead1 · 09-02-2009, 06:13 PM

ts very hard to read plugs these days especially with the friggin alchohol in it. Any real way to check em anymorte w/o a dyno run?

wfolarry · 09-02-2009, 06:16 PM

A lighted magnifier & reading the porcelan center & the ground strap. I have a link to a good read on it on my computer somewhere. If I find it I'll post it.

x1rider · 09-02-2009, 06:27 PM

Thanks for all the input. If it helps a bit, I also had some spitting through the air breather when trying some light acceleration and some pretty loud popping in the exhaust with letting go of the throttle.
Unfortunately, my mechanic had the only dyno around my area and it was sold, now the closest dyno tuner is probably a 10hr drive away.

jim t · 09-04-2009, 04:11 PM

That spitting and popping does sound lean.

vindex1963 · 09-04-2009, 05:11 PM

Quote:

Originally Posted by jim t

That spitting and popping does sound lean.

Yes it does.