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Engine Mechanical TopicsDiscussion for motor builds, cams, head work, stripped bolts and other engine related issues. The good and the bad. If it goes round and around or up and down, post it here.
Screamin’ Eagle platinum plug – around 8K miles on them Had some anti-sieze on threads which is why silver colored. Big Sucker stage 2 intake (lots of air) Slip-ons were Cycle Shack, and changed to Screamin’ Eagle Shorty’s 2K miles ago.
Bike runs flawlessly, no hesitation on hard acceleration, no popping on decel. Bike gets 42mpg riding around on country roads, and 46-48mpg highway. Bike used frequently, 800miles/month. I think the bike might have been tuned by the dealer, there’s no aftermarket tuner to be found on it.
I don't want to spend money on a tune tuner, my main concern is that it's not running too lean & hot.
BIKE #2 - 2008 XL1200R Stock factory plugs – 5K miles on plugs & bike Factory air intake. Slip-ons are V&H, I believe Straight Shots.
Bike runs well, no issues. Unsure of mpg. Bike hasn’t beenused a lot, sitting in garage mostly. No aftermarket tuner.
Bike will get air intake upgrade and some kind of tuning/tuner.
Last edited by Bluesrider.df; Apr 3, 2016 at 04:12 PM.
What to look for on spark plugs is color and the timing mark found on the strap of the plug. As for color brownish red is the target color on the plug. A lot of white means lean condition. The timing mark is line on the spark plug strap that indicates how high the heat is making it up the spark plug. You also want to look at the electrode for a heat mark as well. the ideal heat mark on the strap should be half way on the 90 degree bend and the heat mark on the electrode should be about half way as well. On the base ring if you see jetting or fuel burn off on the ring you are on the rich side as well. If you see color change on the base ring that indicates lean you are in danger of melting your spark plug holes cause then the spark plug is acting as a conductor and passing heat into the head.
Also when looking at spark plugs I find it best to read them after changing them. That will show the most current state of your motor. So change the plugs and take it for a ride for the day. When you get home pull them and look.
Also when looking at spark plugs I find it best to read them after changing them. That will show the most current state of your motor. So change the plugs and take it for a ride for the day. When you get home pull them and look.
The appearance of the plugs will change this quickly? I have 375 miles on the new plugs, I guess it can't hurt to take a look.
I've looked at lots of spark plug pictures online already, but I'm not able to make much of a determination. I was hoping someone with more experience could tell me what they see.
Both plugs are lean. The top plug pictured has no color except for white so I would get that looked at. The bottom plug is a little hard to explain but it appears that low octain gas has been used. The heat damage on the porcelain indicates that the heat is making it up real high. Looking at the spark plug threads it looks like oil is getting in the cylinder
I preface the below comments on the fact that plug reading is correctly done with plug "cuts" using new, never before used plugs, to get a reading at various throttle positions. Trying to read a plug with 5K-8K miles on it will give general idea of what is going on in the combustion chamber but not what is going on at various throttle positions.
Heat range on the fist plug looks OK; maybe a bit on the cold side. The base ring indicates a tad lean and the "specs" on the porcelain indicated some pre-ignition/detonation which would give me cause for concern.
Heat range on the second plug is too hot; you could probably go 2 heat ranges cooler. Porcelain color does not truly reveal lean or rich condition but the base ring indicates a rich condition; however, if the cylinder is pumping oil, you cannot rely on the base ring color to read AFR. The cylinder may be pumping a bit of oil so a compression and/or leak down test would be in order. I don't believe that cylinder is pumping too much oil or you would see black spots on the porcelain and the tip would show more carbon deposits after 5K miles. I would say the second plug is OK but would replace with new plugs a heat range cooler, take some plug cuts to read for AFR.
I would not replace with Harley plugs; NGK would be my preferred replacement.
Don't use never seize either. it masks the first three threads which is use to determine heat range as well. Also a short ride will not tell much. Put in a new set of NGK's and ride it for 100 miles to get a reading on the new plugs...
And yea I thought I might have seen some detonation going on but whats with the white specks on both the porcelains and threads. You need to take more care in the handling of your plugs...
Don't use never seize either. it masks the first three threads which is use to determine heat range as well. Also a short ride will not tell much. Put in a new set of NGK's and ride it for 100 miles to get a reading on the new plugs...
And yea I thought I might have seen some detonation going on but whats with the white specks on both the porcelains and threads. You need to take more care in the handling of your plugs...
The '07 is my bike, it had 5K on it when I bought it 8 months ago, (it was basically a garage queen). I've put 6K on it since then and I've done lots of maintenance on it to get it back on track. Fluids, cables/chain adj, etc.
I changed the plugs to NGK DCPR7EIX Iridium last week (400 miles ago), because I wanted to start over with a fresh set and see what they look like. I plan to pull them out tomorrow and take a peek.
The '08 bike is my friend's, he bought it last week, so we're starting from scratch there as well. We put a new set of the NGK's in his bike too.
Here are some pics from the 2007 XL1200C. These are NGK Iridium plugs with 470 miles on them. I think the first pic (to my untrained eye) shows the nice separation between the black and lighter color.
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Requesting spark plug analysis
