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godoy.rafa

Should I replace my plugs if there's nothing wrong?

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godoy.rafa

Bike runs great, fuel consumption is good. Bought with 35.000KM and now it has 47.000KM. I have no idea when the plugs were replaced.

Should I replace them if everything is fine?

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gregjet

If it has fine wire plugs in it they can last a very long time. Fuel economy is usually the first sign.

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r1limited

I replace my plugs 1 time a year, regardless, that is just me and how I roll.

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AlbatrossCafe

Great question. I have always replaced my plugs every 8k miles (now at 28k) as the owner's manual specified.

 

When I took them out, they definitely looked used. But my bike never had any problems as you have said. I wonder if I could just leave them. I wouldn't want my Cylinders to start misfiring if they get too bad, I would think isn't good for the engine.

 

My 8000 mile plugs below:

 

KNwO3Vn.jpg

pmpZVGD.jpg

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shinyribs

I talked to a guy I know whom I trust ( not that I don't trust anyone where) about this concerning his own FZ07. He changed his plugs around the 15k miles range and saw no noticeable wear/erosion to the electrodes. He also saw no performance increase of any kind with the new plugs. 

 

That said, I'm at 12k miles and just picked up a set for my bike. Not sure when I'll put them in, though. I haven't seen any drop in fuel mileage, performance or idle quality. I mainly want to change them solely based on time and because I know what removing siezed plugs is like. I know our plugs are long and skinny, and that's a recipe for a stuck fastener. I'd like to get some anitsieze in there soon, so I'll be swapping them out. 

Edited by shinyribs
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godoy.rafa
13 hours ago, AlbatrossCafe said:

Great question. I have always replaced my plugs every 8k miles (now at 28k) as the owner's manual specified.

 

When I took them out, they definitely looked used. But my bike never had any problems as you have said. I wonder if I could just leave them. I wouldn't want my Cylinders to start misfiring if they get too bad, I would think isn't good for the engine.

 

My 8000 mile plugs below:

 

KNwO3Vn.jpg

pmpZVGD.jpg

They sure look ugly and worn! I have always changed plugs in cars and bikes as the manual says and also never noticed any improvement.

 

That said, my dad only changes plugs when his car shows some problems like bad idle or poor fuel comsumption, and his old plugs look very bad. In this case he notices an instant improvement of course.

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r1limited

Just FYI

Always use anti-seaze

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Beemer

My father was an aircraft mechanic and he told me that if the engine is starting up quick, that it's running well and getting good mpg. that the spark plugs are performing just like new. Do we change out new spark plugs when they're working good? You have your answer.

Tip: My dad also told me that lugging an engine was not good for spark plugs so to ensure they didn't gunk up he would occasionally wring his cars out at high rpm to (what he called) "burn off some carbon". 

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Beemer
16 hours ago, AlbatrossCafe said:

Great question. I have always replaced my plugs every 8k miles (now at 28k) as the owner's manual specified.

 

When I took them out, they definitely looked used. But my bike never had any problems as you have said. I wonder if I could just leave them. I wouldn't want my Cylinders to start misfiring if they get too bad, I would think isn't good for the engine.

 

My 8000 mile plugs below:

 

KNwO3Vn.jpg

pmpZVGD.jpg

Thanks to Rick, I myself just found out that those plugs are rated for 30k miles by the plug manufacturer. Look at the specs at the bottom. Someone needs to make a thread about this so people don't waste so much time and money on plugs.

https://www.ngk.com/product.aspx?zpid=41476

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DewMan
20 minutes ago, Beemer said:

Thanks to Rick, I myself just found out that those plugs are rated for 30k miles by the plug manufacturer. Look at the specs at the bottom. Someone needs to make a thread about this so people don't waste so much time and money on plugs.

https://www.ngk.com/product.aspx?zpid=41476

The issue I have is assuming that the 30k mile range, that@rick mentioned, of the plugs is based upon much lower average RPM (1-2k) automotive use than the normally much higher average RPM (3-4k) Motorcycle use.

 

As shown in the screengrab below, this is listed as an automotive plug.

 

With this information I can see both the NGK website and the Yamaha Owners Manual both being correct. ✌️

 

NGKLMAR8A-9.thumb.JPG.b9b6499705f1664c3dc77fc8708d7ac4.JPG

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ElGonzales

In the german owners manual the maintenance schedule says: new spark plugs every 20k kilometers. This equals ~12,4k miles, if I am not wrong. Maybe we should also think about  company strategy and possible warranty claims. People want long maintenance intervals, dealers want to make money.  

 

Perhaps the 30k miles specification of NGK  will work, but requires a readjustment of the electrode gap after some time. 

But with such a pain in the ass  to reach the plugs, you can also do a replacement right away. 

 

At my old MZ ETZ 250 from socialist GDR i need 15 secs. to hold the plug in my hands.   

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Cruizin
1 hour ago, Beemer said:

My father was an aircraft mechanic and he told me that if the engine is starting up quick, that it's running well and getting good mpg. that the spark plugs are performing just like new. Do we change out new spark plugs when they're working good? You have your answer.

Tip: My dad also told me that lugging an engine was not good for spark plugs so to ensure they didn't gunk up he would occasionally wring his cars out at high rpm to (what he called) "burn off some carbon". 

It's heat range that dictates if spark plugs get gunked up, not rpm, on road vehicles. 

 

Even at idle, a spark plug rated at proper heat range for the particular engine will self-clean, at any rpm.  

 

OEM spark plugs have the proper heat range for the FZ-07 engine, even with nitrous or whatever mods you do to the engine. The only time you have to drop heat range is if you add 100 or more HP, which would be impossible on the stock FZ-07 pistons and valvetrain. 

 

High RPM has the same effect on a sparkplug as Idle RPM on a non aircraft engine. Nowe, if your bike over heats and your head's cooling jacket can no longer absorb the heat from the sparkplug, then you get fouling and detonation and plug fouling. 

 

Want to keep your plugs clean? Don't over heat your engine, change your cooling fluid at proper intervals. 

 

 

 

 

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rick

Well, spark plugs do wear out. Whether they get sooted up or not is a whole other issue. Mostly these days with lean mixtures, plugs will stay quite clean. But with time, the gap will get bigger. The edge of the center electrode will also start to round over a tad as this is where the spark jumps from. Both of these will weaken the spark with time and degrade performance.

 

Personally, if I found plugs looking worn like this, I'd just pitch them as opposed to filing the center electrode flat and then recapping -  now that would sure be old school.

 

Before there were electronics, motorcycles would frequently have 1 coil firing 2 cylinders. Lots of times that resulted in the plug firing on the exhaust stroke as well as compression - that wore out plugs even faster. 

 

I suspect that Yamaha, in a quest to keep performance sharp and emissions clean, is being very conservative with the service interval - aka our time and money. 

 

I'd not go 30k miles with these plugs w/o looking (valve inspection would come around sooner anyway), but I'd be tempted to go 12 or so before having a look - especially if fuel mileage has not dropped or those no other indications something's not running right. 

 

 

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rick
3 hours ago, Beemer said:

Thanks to Rick, I myself just found out that those plugs are rated for 30k miles by the plug manufacturer. Look at the specs at the bottom. Someone needs to make a thread about this so people don't waste so much time and money on plugs.

https://www.ngk.com/product.aspx?zpid=41476

 

Aside from the soot around the threads (where it really doesn't matter), I don't really see any real wear on either the center electrodes or the grounds on those plugs. If I'd just pulled those out and after putting a round feeler gauge thru the gap (not suppose to use flat feeler gauges with plugs) and found them within spec., I'd  be tempted to just put em back in. Just be careful with retorting as the gasket will already be crushed. 

 

More likely, I'd put the new ones (sitting there) in and just extend the interval next time out say 50% more. If that still results in a decent looking plug, then I'd bump the interval to 16k

 

My Aprilia's plugs have a 10k schedule. They'll look decent after 10k miles, but the motor will have a sharper feel to it. 

Edited by rick
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gregjet

Rick finally mentioned the elephant in the room. The carbon should not be going that far up the threads. That means the plug is a garbage fit in the head. R1's suggestion of antiseize may help the bleed. That much slop will effect the heat draw from the plug. The electrode looks like it is running a bit hot.

Plugs are ( relatively) cheap. If you have them out stick, some new ones, in rather than reassemble, and have to drag it apart and take them out again a bit later.

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rick

Ya know, while we're talking about the threads getting gooked up, the plugs seal up at the gasket not the threads, but  that might cause some issues if the plugs stayed in there 30k miles! Maybe stripped plug hole threads is something Yamaha knows and doesn't want to share.

 

sooooo many threads, lol. pretty sure that's the longest reach spark plug I've ever seen. 

 

But something that just caught my eye was the corrosion on the gasket and metal center of just the one plug. That means moisture is either getting past the coil's seal at the top or the well or that plug did not seal well in. Either way, moisture getting to the spark coil will never do it good. 

 

A good healthy smear of dielectric silicone grease at the top of the valve cover hole and the flange of the coil might prevent that.  

 

 

 

 

Screen Shot 2018-10-17 at 3.49.31 PM.png

Edited by rick
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Beemer
9 hours ago, DewMan said:

The issue I have is assuming that the 30k mile range, that@rick mentioned, of the plugs is based upon much lower average RPM (1-2k) automotive use than the normally much higher average RPM (3-4k) Motorcycle use.

 

As shown in the screengrab below, this is listed as an automotive plug.

 

With this information I can see both the NGK website and the Yamaha Owners Manual both being correct. ✌️

 

NGKLMAR8A-9.thumb.JPG.b9b6499705f1664c3dc77fc8708d7ac4.JPG

Good catch there! It can't be argued that heat is an engines worst enemy so this may be very significant also.

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Beemer
10 hours ago, Cruizin said:

It's heat range that dictates if spark plugs get gunked up, not rpm, on road vehicles. 

 

Even at idle, a spark plug rated at proper heat range for the particular engine will self-clean, at any rpm.  

 

OEM spark plugs have the proper heat range for the FZ-07 engine, even with nitrous or whatever mods you do to the engine. The only time you have to drop heat range is if you add 100 or more HP, which would be impossible on the stock FZ-07 pistons and valvetrain. 

 

High RPM has the same effect on a sparkplug as Idle RPM on a non aircraft engine. Nowe, if your bike over heats and your head's cooling jacket can no longer absorb the heat from the sparkplug, then you get fouling and detonation and plug fouling. 

 

Want to keep your plugs clean? Don't over heat your engine, change your cooling fluid at proper intervals. 

 

 

 

 

I don't know if it makes any difference to it or not but what my dad 'specifically' said ( I took it as meaning he was talking about the plugs, maybe he meant something else other than the plugs???) was that it's not good to lug a cars engine. Then again he was talking about older cars, not todays newer ones so is it possible he was right about not lugging the old cars? I've heard that same thing many times through the years from other people so I can't help but think there's something to it, or at least there used to be. What say you mechanics?

 

@gody.rafa It's a slow process for a spark plug to go bad. Doubtful that anything catastrophic is going to happen to it suddenly. You shouldn't have anything to worry about.

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norcal616

nobody talks about cutting the threads off to read the "plug" these days... 

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shinyribs
11 hours ago, DewMan said:

The issue I have is assuming that the 30k mile range, that@rick mentioned, of the plugs is based upon much lower average RPM (1-2k) automotive use than the normally much higher average RPM (3-4k) Motorcycle use.

 

As shown in the screengrab below, this is listed as an automotive plug.

 

With this information I can see both the NGK website and the Yamaha Owners Manual both being correct. ✌️

 

NGKLMAR8A-9.thumb.JPG.b9b6499705f1664c3dc77fc8708d7ac4.JPG

Good point, but after thinking about it for a bit...our bikes can turn some pretty decent rpms, but we only cruise at around 5k rpm on the highway. I've seen some old Honda 4 banger cars that damn near spin that fast on the open road. 

8 hours ago, gregjet said:

Rick finally mentioned the elephant in the room. The carbon should not be going that far up the threads. That means the plug is a garbage fit in the head. R1's suggestion of antiseize may help the bleed. That much slop will effect the heat draw from the plug. The electrode looks like it is running a bit hot.

Plugs are ( relatively) cheap. If you have them out stick, some new ones, in rather than reassemble, and have to drag it apart and take them out again a bit later.

Yeah, if you are in there then it only makes sense to swap fresh plugs in. But I've never seen a plug that didn't have carbon creeping up the threads. I personally don't see that as a sign of anything wrong, so I don't want anyone worrying about that. 

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shinyribs
On 10/17/2018 at 11:07 PM, norcal616 said:

nobody talks about cutting the threads off to read the "plug" these days... 

Cut the plugs just for you! Ok, well, I wanted to see it, too. :D

 

 

Just to add another example to the mix, I changed my plugs this evening. Right under 12k miles and no discernible loss of performance. Full Arrow XKone exhaust on a stock ECU. 90% of the time I run with a DB killer in, but some days I remove it to appease my inner child.

 

Upon removal I did see definite erosion of the electrode and ground strap. Nothing catastrophic, but it was definitely round over. Tried to get a close up shot, but these pics are as close as I could get the camera to work clearly. Gap measured roughly .037". Stock spec is .031-.035"

 

Threads, groundstrap and electrodes show no signs of overheating. There is some small amount of erosion but the pic isn't zoomed in enough to see it clearly. 

tw1asGk.jpg

 

You can somewhat see the erosion in this pic. Notice the electrodes aren't perfectly square. Nice to see a small fuel ring at the base of the porcelain. Tells me the bike isn't dead lean, but there's definitely not a lot of excess fuel there. I didn't see any peppering (detonation) or blistering of the porcelain. I also didn't see any blistering on the groundstrap. I'm confident that this Arrow system is completely safe to run on a stock ECU, IMHO. Your elevation may be different, so...

pOQ37ww.jpg

 

 

The bike does feel fresher now. I recently swapped to a 17t (+1) front sprocket. The past couple thousands miles on the bike coincided with the sprocket change, but they also consisted of long days of blasting interstate at 85ish mph for several hours at a time on road trips. I had noticed recently that the bike shuddered more when lugging it, but I assumed that was just related to the higher gearing. The hill on my driveway that I used to lug up in 2nd gear I had started using 1st gear instead. The bike wasn't struggling in 2nd but it was definitely shuddering more than I like. All that is gone now. It pulls hard and clean from 1500 rpm again. Also, the top end (8,000-10,000) is noticeably peppier now. Again, I figured the bike was feeling "not as fast" as when it was new just due to me being used to it, but no, it needed fresh plugs. 

 

Would love to see a dyno pull on a bike with 12k+ mile plugs, then swap in a fresh set. 

 

Maybe 8k miles is a good interval to get optimum performance from the bike after all? I went 12k miles this time. Maybe I'll go 10k miles next time and pay attention to the luggability better? Or maybe I'll just do them at 8k and not worry about trying to eek a couple thousand more miles from them. 

 

I'm genuinely surprised to see the erosion and feel the performance difference, but I'm a believer now! And the stock plugs were alarmingly loose in the head. Not finger-tight, I still needed a wrench to remove them, but insanely loose. 

 

And just a heads up, pick up a random old school plug boot. It's the perfect extension to snap on to the plug to make threading the fresh plugs back in to the head/ retrieve the loosened plugs a breeze. Plenty of length and grip to get the job done with out risking a crossed thread. The boot grasps the plug just tight enough that it will slip if you do happen to cross a thread. About $3-4 at your local parts place. Leave the seals off and it fits perfect. 

 

11000264_ngk_8022_pri_larg.jpg

 

Sorry for yet another longwinded post...

Edited by shinyribs
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ElGonzales

Now with ~19500 km I have also noticed more vibrations in lower rpms, especially with a cold motor. But just a little bit, I wasn't sure if it is just imagination or normal because of the lower temperatures outside at the moment. I have already bought new plugs, I'm curios if the shuddering goes away. 

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Beemer

@shinyribs

Have any good advice on how to get the caps (coils) off the plugs easier? The first time I attempted to change them out myself they were a total PITA for me with my arthritic hands/fingers. I don't want to snap anything off.

 

Edit: I just checked out "tech tips" and found that cndnmax used two zip tie loops to try and pull the coils off of his spark plugs. It looks like a good method (in my minds eye) so I'll try that but still, if you have a better way please let me know.

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rick
On 10/17/2018 at 10:55 PM, Beemer said:

I don't know if it makes any difference to it or not but what my dad 'specifically' said ( I took it as meaning he was talking about the plugs, maybe he meant something else other than the plugs???) was that it's not good to lug a cars engine. Then again he was talking about older cars, not todays newer ones so is it possible he was right about not lugging the old cars? I've heard that same thing many times through the years from other people so I can't help but think there's something to it, or at least there used to be. What say you mechanics?

 

@gody.rafa It's a slow process for a spark plug to go bad. Doubtful that anything catastrophic is going to happen to it suddenly. You shouldn't have anything to worry about.

With the reality that pistons come to a complete stop at both the top and bottoms of their strokes, it's inertia (flywheel) that helps keep the motor spinning. If you put a high load (tall gear, slow speed) on any motor at a low rpm (aka lugging) you are injuring to the crank bearings as well as wrist pins. When accelerating, it's always better to have the motor exerting torque on the driven wheels, instead of the other way round

 

The smaller the motor, the worse this becomes. With today's cars getting heavier and heavier and motors nowhere near the displacement of the old V8s that I grew up with, this is why modern car motors are spinning far faster than an old 400 cu in V8 pushing similar weight

 

Same goes for bike motors - maybe even more so. 

 

Don't know the spark plugs would know one way or the other in a modern FI motor

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norcal616
13 minutes ago, Beemer said:

@shinyribs

Have any good advice on how to get the caps (coil) off the plugs easier. The first time I attempted to change them out myself they were a total PITA for me with my arthritic hands/fingers. I don't want to snap anything off.

that small hole I circled is a drain/vent from the spark plug boot area: you can shoot a nice blast of compressed air up there to help break the boot loose...

20181020_100146_20181020100628280.jpg

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