Spark plugs

[commander]

Hello what is a good spark plug for a 75 850T , brand and number, thanks.
Forgot, were can i get some idle jets for the stock carbs ?

[Guzzistajohn]

NGK B6ES for a ‘83 850 <shrug>

[guzzisteve]

I don't use NGK , Champion N4's or N9YC  jet's & carb parts from Herdan in Port Clinton, PA or MG Cycle
Herdan is a DelOrto importer

[F-22]

I was told by many people to not even consider anything but NGK in a vintage air cooled engine. Not only for bikes, but also air cooled VWs supposedly work best with NGK plugs. For Guzzis I think B7ES or B6ES are correct. Don't buy the BR version (e.g. BR7ES). It has a resistor and is only suitable for modern electronic ignitions. The vanadium or platinum plugs are also all the resistor type and shouldn't be used on vintage bikes.

[Antietam Classic Cycle]

The only plugs I use are NGK! Never a single issue in the last 20 years. 

Commander: NGK BP6ES. Jets are just a few clicks away: http://www.mgcycle.com/index.php?main_page=product_info&cPath=62&products_id=628 If the #50 isn't the size you desire, click around in the carb section to find others.

[acogoff]

     Ditto- NGK BP6ES. 

[Aldo]

+1 on the NGK BP6ES.  That is all I have ever used on my Tonti Guzzi's.

[Guzzistajohn]

Used NGK since the BULTACO days- No issues

[guzzisteve]

They allways turned to crap for me, especially if gas wet fouled. Plus I could get champs at Farm&Fleet for $1
NGKs I use in newer Guzzi's 06-on.

Years ago we used to say it stood for NoGoodKrap

[Don G]

I agree with Guzzisteve , found that some bikes don't like NGK, especially the old Brits, put in two new NGK's shortly there after you will have a single cylinder twin , must be due to carburation with the sloppy Amals , Champions were far more tolerant.  DonG

[Chuck in Indiana]

The only plugs I use are NGK! Never a single issue in the last 20 years. 

Me, too. I have an aircraft spark plug tester that I have made an adapter for automotive plugs. The "only" plugs I've tested that were dead out of the box were Champion. (2 of em)
BTW, they will perfectly mimic a failing coil. Don't ask me how I know.. 

[Antietam Classic Cycle]

It used to be that Champions were more prone to stripping threads as well. IIRC, it was due to rolled threads vs. cut threads.

If a customer doesn't want/like NGKs, then Bosch gets the nod.

[guzzisteve]

Me, too. I have an aircraft spark plug tester that I have made an adapter for automotive plugs. The "only" plugs I've tested that were dead out of the box were Champion. (2 of em)
BTW, they will perfectly mimic a failing coil. Don't ask me how I know.. 

AND those are ones for a Lario, they are junk in that size. I used NGK's in them. I used Accel, ND, Bosch, Beru, I tried all sorts.

[bigbikerrick]

What is the problem with running the NGK plugs with the platinum, or whatever it is center electrode? I have those in my cal II, and Lemans which both have the dyna III ignition, and 5 ohm  Dyna coils. I have not had any issues, or noticed any difference in mileage, or the way the bikes perform, with those plugs.
Rick.

[Rough Edge racing]

I agree with Guzzisteve , found that some bikes don't like NGK, especially the old Brits, put in two new NGK's shortly there after you will have a single cylinder twin , must be due to carburation with the sloppy Amals , Champions were far more tolerant.  DonG

 My vintage Triumph land speed racer set several national speed records on NGK plugs...My vintage Triumph street bike as well as most guys I know of with Brit bikes use NGK's...........This NGK #9 Competition plug is from my naked frame 650 Triumph when it ran 133.2 mph

             

  I would like to know what makes brand A better than brand B in certain engines...

[Chuck in Indiana]

What is the problem with running the NGK plugs with the platinum, or whatever it is center electrode? I have those in my cal II, and Lemans which both have the dyna III ignition, and 5 ohm  Dyna coils. I have not had any issues, or noticed any difference in mileage, or the way the bikes perform, with those plugs.
Rick.

Nothing wrong with them except they are mondo expensive. (Guzzi content) They *will* last a long time. We were in the pits with the Guzzi race bike Jim Baron was working on. He gave the Kid a pair of those to put in. Brad gave him the WTF look. Jim said, "I know, there is no performance gain, but the owner wants them in there."
He told me that any time a plug comes out of a bike he's working on, a new one goes in.. so there is really no reason to put those expensive plugs in.

[Wayne Orwig]

  I would like to know what makes brand A better than brand B in certain engines...

My Honda XL600 will foul an NGK, but Nippon Denso will run fine. The reason IMHO is that the heat ranges are not matched. The ND plug simply runs a touch hotter then the NGK, so it stays cleaner.

I had a cousin that worked for Champion for a long time. On his advice I avoid using Champion. I have also seen Champions were the ceramic fell apart inside the motor. NGK has always worked very well in my Guzzis.

[F-22]

What is the problem with running the NGK plugs with the platinum, or whatever it is center electrode? I have those in my cal II, and Lemans which both have the dyna III ignition, and 5 ohm  Dyna coils. I have not had any issues, or noticed any difference in mileage, or the way the bikes perform, with those plugs.
Rick.

Despite what the manufacturer may advertise, they do not make the spark any "stronger". They say they require less voltage. However, voltage is not power, as far as I know that just means it requires a lot more current to produce the same power. I guess it needs more current because the iridium or platinum does not conduct as well as the standard plugs?

Anyway, I will always advise against them on older bikes. They are far too expensive to justify for older bikes where there's a much higher chance of fouling them, in which case they're worthless no matter what the tips are made of...

Besides, I think all the iridium/platinum plugs on the market have a resistor built in. Okay for strong modern ignition, but as far as I know not great for older ignitions. Couple that with the 5k ohm resistor caps which are the most common today and owners often unknowingly make their ignition considerably weaker.

If the manual calls for these tipes of plugs, as is the case on many modern vehicles, you should use them (in those cases I think the stock ignition system is so strong it would require too frequent service intervals with standard plugs).

[Furbo]

Last time I was running 70's guzzi's I used the NGK BPR8ES or equivalent. (Autolite 63's came in a handy two pack!) It wasn't until I picked up the carb sport that I began using the BPR6ES, which is a hotter plug.

Oddly, Laverda were the only manufacturer that I knew that really made a stink about plugs....you simply MUST use the Champion N9YC!  Failure to do so would cause the company to go out of business! ................So, I guess about a decade before I got my first 750SF, some  jackass stuck an NGK B9ES into his mill, and sure enough....poof. 

[Two Checks]

Funny, the plugs that require the most voltage to fire are recommended for vehicles with lower voltage ignition.
Copper plugs still have a nickel alloy center electrode. It is softer than platinum so it wears quicker. Platinum is harder than nickel so they can use a smaller diameter center electrode which requires lower voltage to fire.


Btw- multiple side electrodes do only one thing besides take your money. Since the spark will only jump to one electrode the side electrodes last longer.

[F-22]

However, the side-electrode ones generally are not adjustable...

Like I wrote before, voltage is not power. If the spark has the same power, a plug that requires less voltage will also require more current. Not sure how this really translates to performance, I think most of those "better spark" claims are just some misleading advertisement. I think race bikes do not use iridium or platinum plugs.

[Wayne Orwig]

The platinum can hold a small, sharp, tip longer, so it tends to need less voltage over many miles. You get a spark at a lower voltage with a small area. A large spark plug tip will need a higher voltage.

Not saying it is worth anything. I only use them where the manufacturer says you need to. My 2 valve Guzzis always got simple NGK BPR6ES plugs.

[Don G]

I noticed one time that a N3G Champion would make a bigger spark Kernel than a regular N3 plug, I observed this using my old Champion plug cleaner, so I guess the finer precious metal electrodes do produce a better spark.  DonG