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Help reading plugs? Oil in plug well?

2K views 15 replies 5 participants last post by  wmsonta 
#1 ·
From what I"m reading the oil in my right rear plug well is probably from a bad plug well o-ring?

Here's what my plugs look like. What do you guys think? I don't know how to read plugs very well and I'm trying to get this thing tuned after an ear shave/coaster/jetting. I think I took the pilots up one size and mains up 1 in front, 2 in rear per forum suggestions. Idle screws didn't seem to change the idling at all, despite what I've read, so I set them back to stock 2.5 turns out. Bike is an otherwise unmodified 86, stock exhaust. Thanks.

 
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#2 ·
Oil in the plug well is most likely from a bad oring. It's easy to remove the plug well
& change the o-ring.

The rear axle nut is supposed to fit for removing it.


I'm no good with plugs.
 
#4 ·
To assess the mixture strength by the colour of the spark plugs you have to cut the engine at the rpm you are checking. So, if you want to know, say the mixture the main jet is supplying, you need to have the engine warmed up and running under load at the throttle opening of at least 3/4, hold it for a short while and then cut the engine. This is called a plug chop. If you let the engine run down and tick over it may well mask what is happening by overlaying the mixture at tickover.
 
#6 ·
Yes, at least.

I probably do more tuning than most. Hotrods, etc. I gave up 'jetting to the plugs' along time ago. With modern pump gas, I consider it to be a total waste of time. I could go though how I determined this. Without a drag strip or an accurate means of timing + a lot of effort, people could not duplicate my results.

A smart man with 40 yrs of tuning says it became impossible when the dye was removed from the gas. He makes a good case.
 
#11 ·
You can tell if it is dangerously lean. You can tell if it is pig rich. You can usually get a decent read on the timing (can not be easily changed on the vn).

If you find it necessary to differentiate between about 10/1 and about 15/1 with just the plugs, my advise is to give up.

There is a sticky here on the pilot circuit. The main is next and should be done with quarter mile mph or other accurate measurement. Needle height is last, and should be adjusted to provide the SMOOTHEST transition from pilot to just main circuit.

HTH
 
#8 ·
Tighten up the rear left sleave....other 3 are fine....a few deposits, but far from bad.....and 2.5 turns on the idles is stock ??? Should be 1 5/8 turns out. You shouldnt go more than 2 with a stock exhaust....."mebbe" 2 1/4 turns TOPS. More than that is for modified exhaust.
Some people here say that as soon as you earshave, you need to rejet....thats bullsheit....ONE person here said it ages ago, and the sheep followed....re-jetting is only needed after modifying an exhaust. It dont matter how much air you put in, if it still gets out at the same rate.
Ive experimented with 5 different exhaust systems on my bike, and only the most open requires a rejet....regardless of whats been done to intake....
 
#9 ·
Thanks for the replies. Well I know it was set back to stock so it must have been about 1.5 and it's just my memory failing me on the number.

I think I'm +1 size on the front and +2 rear, +1 on both idle jets and I might drill the baffles. Does it look safe to drop down to +0/+1, or even back to stock? I hate "only" 44 mpg mixed, but I hate burnt valves more.

I guess I'll go do the plug chop minus cutting the plugs up later this week. I can't afford to chop up good plugs at the moment.
 
#10 · (Edited)
Tighten the sleeve first before ya do all that.....it could very well just "go away".....I prefer my plugs a tiny bit browner than yours, but yours are fine...."chalk white" is when ya gotta worry about fryin stuff....yours aint there....

Those deposits flaking off could just be crappy gas (try high test for one tank after you tighten that sleeve)......they really dont look bad....just the one....and the other side is fine....so, tells me, its the way that plug is seating....if it was a carb issue, both rears would look the same....right ?....
 
#12 ·
You don't need to cut the plugs up. It is called a plug "chop" because you "chop" the engine dead at the revs you want to check the colour. As has already been stated this is not as revealing with todays fuel.
 
#13 ·
....they'll never learn Gibbie....oh sheit....hope you dont mind I called you that....sorry.....I just figured, old codge to old codge *nudge nudge wink wink*...lol :beerchug:
 
#15 ·
Yeah, I know about "chopping" the throttle, but I can't see the base of the insulators without cutting the threads off like I've seen some old timers do. I think I'll start sizing down until it's just too lean, then go back up one jet size from there. Thanks for the help.
 
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