Iridium IX installed but there is a noise

[zzkenoman]

I installed new Iridium IX sparkplugs and did a TBS, however when I quickly rev the engine, there is a slight knocking noise. If I roll the throttle slowly the noise is not there. Do these new plugs need higher octane gas because the burn characteristics are different with a non oem plug? Any idea?

 

[Ignacio]

I can think of only two things.

1) All gapped the same and to spec?

2) You got all the vacuum covers back and secure after the TBS?

 

[zzkenoman]

I can think of only two things.
1) All gapped the same and to spec?

2) You got all the vacuum covers back and secure after the TBS?

all gaps to spec, and all caps on after tbs.

 

[Windjammer]

Did you perform standard idle TBS or the Unauthorized TBS? Either way, recheck the TBS and see if that helps. I can't imagine plugs making a dramatic difference unless they were actually defective or the wrong plug for the bike. That being the case, TBS is the only other thing you changed since it last worked "normally" or as you expect it to. Process of elimination.

Good luck!

 

[Randy]

Another possibility is that one/some of the plugs weren't tightened far enough.

 

[radman]

I cannot think of any relation between the two. Unless the plug was the wrong length, but that would make noise constantly, and be unmistakable. I suspect the noise has always been there, and paranoia has reared it's ugly head. In any case, if it is really bad, and/or it really bothers you, have a pro listen and check it out. It's not anything of consequence, believe me.

 

[zzkenoman]

The plugs where tightened down pretty good, if too good, the clearance from the top of the cylinder heads wouldn't be touching it or would it? The TBS settings were untouched because I had done them the week before and they were "aligned" the same after the new plugs were installed. Could I have a bad rubber cap? All the wire fasteners are secure? Idle was untouched, also. I'll pull the plugs again, but if the problem come back, I might have to put oem plugs back in and see if it does it again.

 

[Randy]

I cannot think of any relation between the two. Unless the plug was the wrong length, but that would make noise constantly, and be unmistakable. I suspect the noise has always been there, and paranoia has reared it's ugly head. In any case, if it is really bad, and/or it really bothers you, have a pro listen and check it out. It's not anything of consequence, believe me.

Was your response to me? If the plug isn't tight enough, air would be escaping when the piston is on the upstroke. I've seen this before and the sound is very similar to an exhaust leak.

 

[radman]

No, "overtightening" could not cause it. Any contact between piston and plug would be obvious, the racket would be horrendous-for a few seconds. Then quiet would reign. You did check to see that all were CR8EIX, correct?

 

[radman]

I cannot think of any relation between the two.  Unless the plug was the wrong length, but that would make noise constantly, and be unmistakable.  I suspect the noise has always been there, and paranoia has reared it's ugly head.  In any case, if it is really bad, and/or it really bothers you, have a pro listen and check it out.  It's not anything of consequence, believe me.

Was your response to me? If the plug isn't tight enough, air would be escaping when the piston is on the upstroke. I've seen this before and the sound is very similar to an exhaust leak.

No, it wasn't. But, a loose plug would make noise constantly, not just on a quick rev as opposed to a slow one. And yes, the exhaust leak analogy is perfect. I suspect he installed, possibly, one wrong plug at most. One cyl may be pinging a bit, but even that is a wild ass guess.

 

[ionbeam]

* Hope you were very careful checking the gap of the iridium plug, they damage very easily.

* We can assume none of the plugs were dropped?

* [Real Possibility] If a spark plug wire was damaged it could cause the type noise you are hearing. When you checked the TB sync, did you find one or more cylinders to be noticeably different than the others? A cylinder with a damaged plug wire wouldn't run as strong as the others. A weak firing cylinder can make a slight knocking noise. [/Real Possibility] Sometimes in low light you can see an errant spark jump. Watch your gas mileage and see if it drops. FWIW, my mileage went up ~1.5-2 mpg when I installed irridums.

Just a few random shots in the dark. Maybe it will 'spark' an idea. (Where is the groan emoticon?)

Alan

 

[radman]

He said the TB's didn't change, so it doesn't appear he's got a sad cyl.

 

[zzkenoman]

No, "overtightening" could not cause it. Any contact between piston and plug would be obvious, the racket would be horrendous-for a few seconds. Then quiet would reign. You did check to see that all were CR8EIX, correct?

The model no. is correct, and no I didn't drop the plugs, and I did double check all the gaps before installing (hey at least its easier than installing plugs on my 79 trans am) the new plugs. The TBS had the same readings before and after the plugs, so I know the plugs were tightened correctly and the idle untouched.

Could it be my fuel? the sound is closer to a bad detonation, but since I dont have any idea about the specs of this plug, whether it is a cooler or hotter plug. I wonder if its cooler and doesn't detonate certain brand fuels (87 octane) very well? Otherwise I will take heed to the advice here, pull the plugs, recheck the gaps. Its really the only thing I did in the engine, nothing else was adjusted, not the tbs or idle.

 

[radman]

The iridiums aren't fuel sensitive, there was no change in Frank when I switched other than the smoother running normally associated with a plug change. Make sure the cap/wire connection is good, and the caps secure on the plugs-they take a healthy push to fully seat.

 

[zzkenoman]

The iridiums aren't fuel sensitive, there was no change in Frank when I switched other than the smoother running normally associated with a plug change. Make sure the cap/wire connection is good, and the caps secure on the plugs-they take a healthy push to fully seat.

rubber boots all secure, until I could finger feel the threads of the plugs while pushing down the boot.

 

[radman]

How many miles are on this thing?

 

[zzkenoman]

How many miles are on this thing?

4500 since october 05

 

[JerseyEd]

Sounds crazy but on some motors (cars) reversed spark plug wire can sound like this problem. I am not sure about a four cycle. I would think on the four it would be a bigger knock. If your are in there I would check wire order. Also a old trick I would try is to run the bike in a completely darken garage and open the trottle looking for a spark. Something may have been pulled loose. Also check the tank lines are loose.

 

[radman]

Well, pop the old plugs back in-see if it changes. I can't for the life of me understand what is wrong, without hearing the sound myself. Wrong heat range (due to a mis-marked plug) wouldn't really be evident until the engine had to work, unless it was a totally incompatible plug. The possibility exists you have a bad one, but that would result in a misfire, not a knock sound. Pre-ignition would be evident throughout the rpm range, usually under load, and not usually present in a free wheel rev. How does the bike ride? Any mis-fires or roughness (possible crossed plug wires, though the coil fires 2 plugs at once, it would be pretty obvious). Is it possible one plug was missing the gasket?