Author Topic: spark plugs  (Read 3499 times)

Offline BSA_54A10

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Re: spark plugs
« Reply #15 on: 16.08. 2011 11:21 »
It all goes back to the price thing.
A modern plug costs $ 4.50 in OZ
The retailer makes $ 1.50
The wholesaler makes $ 1.20
So the maker gets around $ 2.00 to $ 2.80 and they have to package & deliver them to the distributor.
The absolute price has just about remained the same for the last 20 years so some thing has to give and that is both the quality & the quality control.
Complaint to the plug company and their fix will always be use a premium plug ( platinum, etc,etc )
On these plugs there is sufficient profit to ensure a high quality.

And yes modern fuel ( which is not petrol ) will foul plugs very fast. I have seen a lot of plugs, foul on the first kick, brand new straight out of the box. Others have done 1000's of miles without a problem and this is irrespective of brand.
Chances are that every brand of standard plug comes from the same machine in the same Chinese factory.
Bike Beesa

Offline Topdad

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Re: spark plugs
« Reply #16 on: 16.08. 2011 12:05 »
Hi everyone , a friend of mine used to repair ,rebuild and race prepare manx nortons , actually owned a couple as well and I can remember him telling me that a well known (recently deceased )english classic racer ruined one of his motors by forgetting to change from a soft plug when starting to a hard one for the race, the plot only lasted 1 lap and the top end was virtually scrap, so i've always given plug type a fair bit  of consideration although obviously my machines are all reasonably cooking models. regards BobH.
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Online RichardL

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Re: spark plugs
« Reply #17 on: 12.03. 2012 13:24 »
Not following the previous discussion in this thread,  just avoiding starting another topic.

It occurs to me that modern spark plugs are not designed for the small plug gaps we use,  say,  0.018". The result is that the earthed contact must take a steep angle down in order to close the gap to where we want it.  To me,  this seems like it wouldn't make for the best chance of consistent,  low-resistance spark.  Are there any plugs out there, of the conventional type,  that are designed for small gaps?

Richard L.
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Offline Rocket Racer

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Re: spark plugs
« Reply #18 on: 30.04. 2012 04:54 »
Over the weekend we were racing at a colder meeting than usual and the bike was a bugger to start, wanting to run on 1 when it would fire and temperamental even warmed up. We got plenty of exercise pushing
Swapping out the usual B10's for some B9's plugs removed the problem immediately. admittedly on methanol, but very noticable the improvement in low speed running for the cold weather.
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
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