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General Category => General Discussion => Topic started by: John A on September 19, 2021, 12:50:50 PM

Title: Tuning tip
Post by: John A on September 19, 2021, 12:50:50 PM
Doc Harley ‘splains why you should change your spark plugs at 10K miles. Good general information that applies to all  especially with the modern pump gas which he doesn’t mention. In the old days it was considered good practice to use a file to restore sharp edges. With modern fuels once the engine has flooded  the plug porcelain gets contaminated, it takes special methods to clean it which is nearly impossible, according to a tech rep from AC and it causes more problems than it cures. Just replace them at 10K miles, something I’ve not been doing, especially if they are expensive  platinum unless I’m chasing a problem. https://youtu.be/Sk7oguB9ApU
Title: Re: Tuning tip
Post by: John A on September 19, 2021, 06:33:53 PM
Unless the plugs are bad.
Title: Re: Tuning tip
Post by: Stratodisaster on September 20, 2021, 07:26:43 AM
Changing plugs at 10k is a total waste of time and money.
Title: Re: Tuning tip
Post by: John A on September 20, 2021, 09:22:05 AM
Changing plugs at 10k is a total waste of time and money.
.






Agreed, i posted it because it seemed like there was a spate of posts on rough running and misfires. modern plugs work so well they are often overlooked and I have to convince myself to periodically replace them. 
Title: Re: Tuning tip
Post by: Stratodisaster on September 20, 2021, 01:33:10 PM
I ran the originals in my gmc over 140k. It was still running as good as it did with the new replacements. It’s amazing how long things last nowadays. When I was in my teens 100k on a car was rare without major work having been done. If you got to that mileage you couldn’t hardly give it away much less sell it.
Title: Re: Tuning tip
Post by: Chuck in Indiana on September 20, 2021, 02:43:37 PM
I was in the pits with Jim Baron while The Kid was changing plugs in the race bike. He told me every time he removes a plug, he puts in a new one. "You can't believe the problems I've seen that were only fouled plugs."
I've gotta agree. They are two freakin dollars..
Title: Re: Tuning tip
Post by: sib on September 20, 2021, 02:44:59 PM
My 2021 V7 E5 (850) has iridium-tipped plugs and yet the maintenance schedule requires changing them every 10,000 km (~6200 mi).  This doesn't make sense to me.  If you're going to change them that often, then why use iridium tips?  Any insight will be appreciated.
Title: Re: Tuning tip
Post by: Vagrant on September 20, 2021, 02:53:31 PM
Same plug in the V85 is at 18,600 miles. That was probobly intended to have standard plugs.
Title: Re: Tuning tip
Post by: Chuck in Indiana on September 20, 2021, 03:07:27 PM
My 2021 V7 E5 (850) has iridium-tipped plugs and yet the maintenance schedule requires changing them every 10,000 km (~6200 mi).  This doesn't make sense to me. If you're going to change them that often, then why use iridium tips?  Any insight will be appreciated.

Absolutely. The only real value of iridium is extended life.
Title: Re: Tuning tip
Post by: Stratodisaster on September 20, 2021, 04:15:09 PM
If I was racing I might do things differently but I’m not. Iridium and platinum plugs should last between 60 and 150k. On my bike I look at them when I’m doing a valve adjustment. As long as they look good and I’m having no problems I run them.
Title: Re: Tuning tip
Post by: pete mcgee on September 20, 2021, 06:46:38 PM
I can understand the 5000mile change spark plugs of yesteryears. Plain sparkplugs, leaded fuel, poor airfiltration ( yes that means you K & N), weakish coil output etc.
Todays iriium plugs are brilliant and rarely wear or fail.
Using these also greatly reduces wear on the threads that hold the plug in, just remember the anti seize. A mk 3 lemans in heavy rush hour traffic in 34 deg heat spitting a live spark plug agaist your leg IS a learning experience and an unwanted distraction.
I recently removed the iridiums from my sons car at 80, 000 km as the manual called for change, all were a good colour all had the standard gap, no they didnt have antiseize OEM fit from new. They could have gone back in with no issues.
So if you run them maybe pull them every 40,000 km and have a look, change if gap is expanding or theres damage.
Title: Re: Tuning tip
Post by: malik on September 21, 2021, 01:20:10 AM
My 2021 V7 E5 (850) has iridium-tipped plugs and yet the maintenance schedule requires changing them every 10,000 km (~6200 mi).  This doesn't make sense to me.  If you're going to change them that often, then why use iridium tips?  Any insight will be appreciated.

Do note that it often takes some time for Guzzi to update its manuals. I wouldn't be surprised if some of the info & diagrams in the service manual have not been updated either. Situation normal, commonsense recommended.
Title: Re: Tuning tip
Post by: SIR REAL ED on September 21, 2021, 05:53:52 AM
I'm putting on my Carnac hat and predicting that spark plug threads are the new oil threads......

https://www.youtube.com/watch?v=TU346p1SYmQ
Title: Re: Tuning tip
Post by: blu guzz on September 21, 2021, 05:59:27 AM
my 2020 v85, bought in July 2019 has nearly 18,000 miles.  when i did the 12,000 mile service at about 13,000 the plugs looked fine so they went back in.  they also did not look like iridium or platinum or any other special thing, just like regular plugs.  over the past few thousand miles, it has started to be the slightest bit bulky from a cold start as in you push the button and it runs a little rough for about 20 seconds, or advancing the throttle for a few seconds clears it right up so i may try some fresh ones at the 18,000 service.
Title: Re: Tuning tip
Post by: Stratodisaster on September 21, 2021, 07:28:54 AM
I can understand the 5000mile change spark plugs of yesteryears. Plain sparkplugs, leaded fuel, poor airfiltration ( yes that means you K & N), weakish coil output etc.
Todays iriium plugs are brilliant and rarely wear or fail.
Using these also greatly reduces wear on the threads that hold the plug in, just remember the anti seize. A mk 3 lemans in heavy rush hour traffic in 34 deg heat spitting a live spark plug agaist your leg IS a learning experience and an unwanted distraction.
I recently removed the iridiums from my sons car at 80, 000 km as the manual called for change, all were a good colour all had the standard gap, no they didnt have antiseize OEM fit from new. They could have gone back in with no issues.
So if you run them maybe pull them every 40,000 km and have a look, change if gap is expanding or theres damage.
       +1. Well said.
Title: Re: Tuning tip
Post by: sib on September 21, 2021, 07:52:30 AM
So, if I'm going to keep running the iridium plugs for a long time, but still remove the plugs to adjust the valves every 6200 miles, then the spark plug washers will eventually flatten and not do their job.  Are there such things as replacement spark plug washers?  Alternatively, is there a way to adjust valve lash without removing the spark plugs?  Again, any advice will be appreciated.
Title: Re: Tuning tip
Post by: Murray on September 21, 2021, 07:59:25 AM
The thing that used to kill plugs is no longer a thing, lead bromide in fuel.
Title: Re: Tuning tip
Post by: guzziart on September 21, 2021, 08:00:12 AM
FWIW....

https://www.ngk.com/can-old-spark-plugs-be-cleaned
Title: Re: Tuning tip
Post by: Stratodisaster on September 21, 2021, 07:44:37 PM
FWIW....

https://www.ngk.com/can-old-spark-plugs-be-cleaned
.                                                                          More bs. The give away is the part where they say to let the brake cleaner sit for 10 minutes. That’s about 8.5 to 9 minutes of doing nothing
Title: Re: Tuning tip
Post by: SmithSwede on September 21, 2021, 08:45:47 PM
On my V7 Stone, the plugs look pretty grotty after 10 to 12K miles.  Gap noticeably widened, ground wire rounded, all kinds of brown crap on insulator.  I’m not going to file the ground square, or try to re-gap it.  I change them.  They are cheap.  And sure enough, it runs better with fresh plugs. 

In my opinion, you can save money not changing the oil filter so often.  Once every second or third oil change (12 to 18K miles) is fine. 

Same for air filter.  Unless you live 20 miles down a dirt road, I’d run the air filter for 30 to 40K miles. 

In contrast, I like good spark. 
Title: Re: Tuning tip
Post by: Chuck in Indiana on September 22, 2021, 03:39:23 PM
On my V7 Stone, the plugs look pretty grotty after 10 to 12K miles.  Gap noticeably widened, ground wire rounded, all kinds of brown crap on insulator.  I’m not going to file the ground square, or try to re-gap it.  I change them.  They are cheap.  And sure enough, it runs better with fresh plugs. 

In my opinion, you can save money not changing the oil filter so often.  Once every second or third oil change (12 to 18K miles) is fine. 

Same for air filter.  Unless you live 20 miles down a dirt road, I’d run the air filter for 30 to 40K miles. 

In contrast, I like good spark.
Spoken like a high miler..  :thumb: and although I don't do your kind of miles any more, I agree.
Title: Re: Tuning tip
Post by: Mr Revhead on September 24, 2021, 03:48:05 AM
Something to note, you can't tell how good a plug is just by looking at it. You have no idea I'd the resistance has climbed.
Higher resistance means the coils have a harder life. The number one cause of dead coils in modern ignition is plugs and leads not being changed enough and making them work harder