Bonneville America Forums Forums Technical Forums General Tech Spark plug life

I did a 560 kilometre ride today and although I was pushing it along pretty hard in places I think the fuel usage was a bit high.
I'm thinking of getting some new spark plugs to start with and was wondering what kind of miles/kilometre is considered advisable to change plugs on a 2007 Speedmaster and what brand of plugs do others recomend ?

I fouled a plug once, but never since. At that time, I had about 14k on the bike. Ever since that point I just replace them annually. $4/pair here at Autozone, so it's cheap enough. I use the factory plugs:
NGK DPR8EA-9

I think I have 20,000 miles on this set (NGK iridium)

I am setting at 19,000 on mine and am not having a problem yet.

Ive got 23K mile son mine and changed plugs twice, not cause I needed to. Once to got to Iridium plugs and once to go to Nology plugs. I just wanted to see if Id notice a difference.

Hey Z. What are your thoughts on the Iridium plugs? I have a set I haven't put in yet. I ran iridium plugs in my V-Star and they worked out really well with better cold starts, stronger running, and longer life. Do the Triumph motors benefit?

Thx,
H.

Keep in mind I don't keep my bike outside, she has a nice garage. Cold starts can still be a pain for me as I live in Seattle though so....

Overall - I noticed a better running bike with the Iridiums. Yes, better cold starts. I didn't get as loud of a pop on startup as I did with the OEM plugs (when she sits overnight the next morning can result in a pop-backfire on initial startup especially in cold weather).
I can not say I felt an increase in HP but a slightly smoother run through the RPMs was noticeable to me.

I did the Nology coil, plugs and wires all in one shot so that made even more of a difference. Again, I can not speak to HP gains as I don't think this is a HP upgrade but overall a better running bike was noticeable. Easier starts, better revs through the RPMs. Similar to upgrading to the Iridiums but better.

In short my non-professional, no dyno runs impressions is that if you can afford the upgrade the aftermarket ignition system upgrades are a nice to have but not a must have. Ill say that it does make the bike run better.
If your strapped for cash but can afford a couple nicer plugs Iridium), do it.

Oh....FWIW - My Montero Sport runs iridium plugs and they only get changed every 100K.

Excellent feedback, Z. WOW, I didn't know that the iridium plugs lasted that long. Good to know.

Thx,
H.

I was running the iridium plugs.I switched to the E3 plugs. I thought it was a gimmick,but for the same price as the iridium I thought I would try them. I have actually noticed a difference on warming the bike up in the cold here. Before I had to let it warm up longer with the choke on.Now it warms up and I can let it idle with the choke off much sooner. Other than that I can not honestly say I see any difference.I have only had them in there maybe 3000 miles now.Gas mileage seems about the same to me.

24,000 on my stock plugs, had em out a couple times but just checked the gap and put em back.

Thanks everyone for your contributions especially Zmilin.
The Speedmistress has 33500 K's on the clock now and had 18000 on it when I bought it so chances are these are the original plugs. I think I will try a set of NGK Iridiums.

I have 38,000 miles of hard running on my original sparkplugs.
Still running great.