Correct spark plug

[robesetz]

Hello all,
 I know this was posted early last year but the thread didn't help me. I am looking for the correct plug for my 76' 400 MC5. I am using a mini 6 motoplat (9600162-6V35/5/21W32)and a motoplat coil. The manual calls for a Champion L3G or a Bosch W340S1S. I have checked every shop around town with no luck. One shop told me I could use a NGK 7001 which is a platinum plug? I did take from the previous thread that most of you guys don't like champion plugs! Any help would be appreciated. Thanks.

ROB
76' 400 MC5

[TGTech]

Rob,

   I don't know all of the possible choices out there for the various brands of spark plugs, but I can make a recommendation based on our experience with the Motoplat, PVL, and MZ-B ignitions.

   The open class engines turn over at a relatively slow rate compared to the smaller class engines. In order to give the ignition the maximum advantage, you should use the fine wire, precious metal type spark plugs. In the NGK brand, for the short reach heads, what you ought to try and find, are HV, HVX, or HIX type plug. The "H" refers to the short reach thread and the other letters are the specific type of spark plug. As far as the heat range, I'd probably use an 8 for an open class engine. If you can find them, try and find NON-resistor type plugs. If you find an "R" in the nomenclature, i.e. BRH8VX, the "R" refers to a resistor type plug. Today, with all the electronic type ignitions and other digital devices on motorsport equipment, it is becoming harder and harder to find non-resistor type plugs, but if they're available, I'd try and get them.

   One note: I personally have not had any luck with the "G" series NGK's. I don't know why, but that's my personal experience.

   I hope this has been of some help.

Dane

[robesetz]

Dane,
 How would a NGK B9HS work? This is what NGK calls for on their web site for a 77' 400 MX? Thanks.

ROB
76' 400 MC5

[TGTech]

Rob,

   The "S" series spark plugs, are what could be described as "standard" version of the plugs. They have a (comparatively speaking) very thick electrode and aren't as effecient in the use of the current from the ignition. That's why I recommend the fine wire, precious metal type plugs.

   Back in the day, when your bike was manufactured, the "S" series was what was available from NGK. I never used an NGK plug in those days, only Bosch because they had the advanced type plugs.

   I would suggest that if the ignition is in good shape and all your grounds are clean and proper, then probably the "S" series plug will work. The bottom line to me is, now that I know what's available and works best, that's the way I'd go.

Dane

[Kip Kern]

I have had good luck with the Bosch W3AC (standard) and the Bosch W3AS (silver tip, more $$)  These are the crossovers from the old Bosch plugs and work excellent on all the engines both Sachs and KTM

[OUCWBOY]

I agree with Kip. IMO, Bosch still make the very best plugs. There was a reason John Penton installed the Bosch in all the Penton's to begin with.

Donny Smith

[firstturn]

Rob,
  I still have Bosch plugs from the 1970's left over that I bought thinking I would need them.  I recently bought a 1970 Penton and the guy included a box of plugs (Bosch) with one missing and said he only used two plugs in 30 years and the original was included in the items with the bike.  I have used NGK and liked their performance, but I beleive the Bosch was the best for their time.

Ron Carbaugh

[Rain Man]

Rob, I run NGK B8HS in my 77 GS 400, 76 MC5 250 , 73 175 Piners, and all my 125 Sachs. The KTM and Husqvarna run the longer reach  NGK BR8ES

 I like Bosch plugs too, but my "LOCO Auto Parts" carry the NGK due to their popularity with Snowmobiles.


Raymond
 Down East Pentons

[OUCWBOY]

Ray,
If you have an old VW repair shop around, they can order them for you, That's what I did.


Donny Smith

[deek]

Hi All

I found this site that may be helpful for reference.
http://www.ngk.com/

This is not the official NGK site. Look under Vechile Type/power sport/and take it from there. For the Sachs engine B6HS, ran a cross reference on NGK web site to find the Iridium part number. Hope this helps!! Napa Auto Parts, if in your vicinity, is a good source.

http://www.ngkspark.com.au/part_index.htm?http:

//www.ngkspark.com.au/iridium/iridium.php

Dale Walter

[Rain Man]

I read this question and I cant help but reminisce on all the fouled plugs I've left out here in the Western forest of maine.
  Lessee hear, ... how many cylinders on that 2 stroke Polaris.  The Jonsereds that always quit 10 minutes afore ya got the truck full of firewood and of course. none of my katooms have eva fouled a plug... but all the fellas I ride with... looky there, is that a poly wog hanging outta that plug hole...  hehe

Raymond
 Down East Pentons

[tlanders]

I use an NGK B8EG in all my Pentons. It is a platinum plug with long reach, they don't make it in the short reach H plug. I make a 1/4" spacer as a gasket to use the longer plug. They are not resistor plugs and have the fine platinum tip to make a hot spark, not too expensive either, $5 or $6? I know you are supposed to use a 9 heat range for the 400, but I stick with the same plug for all.

Teddy