Spark plug for 350 with tuning

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T Batnes
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Spark plug for 350 with tuning

Postby T Batnes » Tue May 07, 2019 3:15 pm

My 350 iron head has a Franklin P2 cam and a 7,5:1 piston - I take that I should follow the advice in the Ariel singles manual for a 350 with HC piston, and fit either a Lodge R14 or a KLG LB1 spark plug - but these aren't so easy to find. What would be the spark plug to go with? Most riding will be around 30-60 mph, with hills and mountains to climb in rather cool climate here in Norway. I would love to have a pink Lodge or a vintage KLG plug of course, made in England.
Ariel W/NG '41/'43 "Bitzer", Triumph Thruxton '04, IZH-49 '56, Tempo Standard 150 '54.

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Re: Spark plug for 350 with tuning

Postby Simon.Gardiner » Wed May 08, 2019 12:28 am

T Batnes wrote:...I would love to have a pink Lodge or a vintage KLG plug...

Madness :lol:
Fit something that you can readily get in the different heat ranges (these days I swear by NGK but it's only for that reason, the ranges are documented and most suppliers know what I'm talking about!).
You have reminded me that I've not changed my plug since I moved my VH up to a high-comp (7.5:1!!) piston and an HS Mk3 cam - seems to be running OK though....maybe see how it goes with the standard plug and move 'harder' if it doesn't like working hard?

SG
'55 Huntmaster, '56 VH, ' 51 VH, '80 R100RT, '00 Sprint ST (but all those Ariel parts can only make one running bike...)

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Re: Spark plug for 350 with tuning

Postby nevhunter » Wed May 08, 2019 1:19 am

If your plug is too hot it definitely will cause issues if you ride hard so err on the colder side unless you do a lot of traffic crawling. Avoid "R" type plugs if you can as the magneto's like wire and a non R plug. Those old plugs look good when you are being judged or parked somewhere. Cold plugs have shorter and fatter insulators in the part that goes into the combustion chamber if the numbers make no sense. Nev

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T Batnes
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Re: Spark plug for 350 with tuning

Postby T Batnes » Wed May 08, 2019 8:58 am

:lol: Good answers and advice are for free in this forum, like it! I will get NGK plugs then. Just that I heard some old guys not liking them too much in their old english bikes, and used mainly Champion and Lodge.
NGK is what I use in my two strokes, and they never fail. B6HS is standard for Ariel iron head singles I can see from Draganfly, and the colder B7HS should be good for more spirited rides. Think B7HS is what I use in my IZH-49 350 in fact, so I might have a box of those in a drawer somewhere.
Ariel W/NG '41/'43 "Bitzer", Triumph Thruxton '04, IZH-49 '56, Tempo Standard 150 '54.

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Eero.Korhonen
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Re: Spark plug for 350 with tuning

Postby Eero.Korhonen » Wed May 08, 2019 9:01 am

I would go for Champion L82 maybe? And in my IZH I use Bosch.
Br, Eero
Ariel VH 1954, IZH 350 1962, H-D Sportster Hugger 1992, AOMCC Member 133

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Re: Spark plug for 350 with tuning

Postby Brian Petheram » Wed May 08, 2019 9:30 am

I much prefer old spark plugs in old engines - modern plugs always seem to be a bit of a lottery to me and too many have prematurely failed or caused problems in my old bikes. I always snap up any NOS spark plugs from the likes of KLG, Lodge and Champion and find they work really well and seem to last forever. A couple of my bikes are running on mica insulated plugs.
Here is an explanation from a reputable source of why modern plugs may be less suitable for older engines:
https://www.gsparkplug.com/shop/fouling ... ion-vs-ngk
I'm sure Rick Partington of Classic Bike has made the same points but I can't find the reference. Looking at what a plug is and how they are made, I can't see why one left in a tin for 50 years or so would not be perfectly servicable.

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Re: Spark plug for 350 with tuning

Postby Simon.Gardiner » Wed May 08, 2019 2:09 pm

Unfortunately I don't have a shed full of NOS Champion/Lodge/KLG spark plugs and I don't know of anyone who can sell 'em to me 'over the counter' , I have to go with what I can reliably get my hands on fairly quickly (or not use the bike...).
I think all 'modern' manufacturers make to a cost - last time I bought Bosch plugs for the BM they were made in India - and I could only get the right ones from a BM dealer and at BM dealer prices, so the BM has been on NGKs for years. I haven't noticed any change in the service life of the plugs - the last couple of sets have lasted for several years. The NGKs in my modern(ish) Triumph last forever, as do the NGKs in my 'A'-series-engined Austin Metro.
I did use to only use Champions in my older non-German vehicles but since I've not been able to get those locally (many years now) that had to stop. However, if Champion/Bosch/Denso were easier to source than NGK I'd change again.
The Champions weren't always reliable, especially in the old Brit bikes. I think we tried some Lodge plugs without any more success - and I'm going back to experience from the early 1970s here, which pre-dates the supposed change to 'unsatisfactory' plug manufacture cited by one of the sources in the 'Green Spark Plug Co' article. (I'm not going to put that down as complete rubbish but I haven't noticed having to change the starting technique on the Ariel from what I used to do back in 1972 - I will admit though that I've never had the chance to try genuine 1950s spark plugs.)
I have heard of problems with 'fake' spark plugs (ie poor quality items branded and sold as coming from one of the established names) - I'd think you'd avoid that if you stuck to NOS plugs but these days somebody might well end up faking those as well.

SG
'55 Huntmaster, '56 VH, ' 51 VH, '80 R100RT, '00 Sprint ST (but all those Ariel parts can only make one running bike...)

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Re: Spark plug for 350 with tuning

Postby chris.vredenbregt » Wed May 08, 2019 2:58 pm

I race with my AJS 500 1949 with champion N 82 the short version of the L type ( Iron head) never had a probleme and we do rev more than normal
black ariel model G special 1930 500 OHV

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Re: Spark plug for 350 with tuning

Postby JohnnyBeckett » Wed May 08, 2019 10:13 pm

i use ngk in all my motorcycles and race cars for the last 40 years use non R plugs and caps on mags i use them all the time in my workshops ring NGK they will help you they are very helpfull

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Eero.Korhonen
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Re: Spark plug for 350 with tuning

Postby Eero.Korhonen » Thu May 09, 2019 5:27 am

I usually buy these Champion from ebay and I get couple of those, because you can not get them from stores.
Br, Eero
Ariel VH 1954, IZH 350 1962, H-D Sportster Hugger 1992, AOMCC Member 133


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