A10 1958 Gold Flash spark plug

[Ian]

Can anyone recommend a spark plug brand and type presently I'm using NGK B6H S. I appear to be getting through them at a rate of knots and wondered if there's a better alternative.
I'm also wondering if it's the unleaded petrol that the issue? Surely plugs made today would be engineered with this in mind.
Has anyone experience of using a petrol catalyst?
As usual any advice gratefully received.

[BSA_54A10]

Go one hotter to a BP5HS.
What do you mean by "go through" ?
I was fouling plugs left right & center till I got into the habit of running the carb dry to stop rather than killing the maggy.
When you kill the maggy the engine still spins 4 or 5 revolutions so you suck in fuel that the plug can not burn if the plug is not hot enough this fuel will lave a conductive coating over the plug so the bike won't start next time.
Seemed to be a bit random which always threw me,
If they re going bad on a cold start then you are jetted just a tad rich.
Never try to mechanically clean one with a brush as the brush will leave conductive streaks on the center electrode.


And no modern plugs are engineered to work in modern fuel injected computer controlled cars not anchient fixed ratio motorcycles.

[Triton Thrasher]

First, have you renewed the needle jet?

I was fouling plugs left right & center till I got into the habit of running the carb dry to stop rather than killing the maggy.
When you kill the maggy the engine still spins 4 or 5 revolutions so you suck in fuel that the plug can not burn if the plug is not hot enough this fuel will lave a conductive coating over the plug so the bike won't start next time.

My bike has a magneto, but it doesn't do that.

Never try to mechanically clean one with a brush as the brush will leave conductive streaks on the center electrode.

A steel wire brush doesn't do that. I've cleaned hundreds like that and it works.

[Rocket Racer]

After many years of happy NGK use, I have returned to using champions following some plug issues and on the particular bike (the a75), it has greatly improved starting and slow running. My FIL did the same to his '74 benelli S2 and likewise has found champions can clean themselves up once fouled (eg would chime in on the other cylinder that was not running cleanly), whereas the new NGK's kept fouling and wouldn't run on both cylinders.
An university engineering lecturer (also a classic bike owner) put me onto this course of action. Apparently all to do with the way the enamel is not glazed as well as it used to be (not necessary for modern engines with more stringent fuel and ignition management). I'm no expert but it made a difference so I've now switched all three road beesa's back to champions.

Just my 10 cents worth.

[Peter in Aus]

Back in the days of old when I had a new 54 A7 SA (now they were the days, b.... fool sold it, traded it in on a FX Holder, more fun with the girls on the back seat, u just don't get your priorities right when young!) I decided to change the plugs after doing some considerable miles, I put a set of KLG plugs in (now there is a blast from the past KLG) it was good for a few 100 miles, but on my way into work one morning  running late as usual at 80MPH (it would do a ton no speed cameras then) it started to what I though was the engine seizing up, but it was the spark plugs, I got a set of Champion plugs and never had a problem after that.http://www.a7a10.net/forum/Smileys/default/icon_wink.gif
Peter 

[groily]

Plugs can be funny things, obviously, but I've been running the same set of NGK B6HS in my iron head for tens of thousands of miles.  (Also on my B31.) The only other plugs I have run on were Bosch forgotten-whats, also OK. (I don't tend to run at full throttle though, I'm a 2/3rds kind of bloke, so maybe I haven't tested them hard enough!.)
No additives in the unleaded - I use the '98' petrol, because when I have used the lower grade '95' stuff (mostly 'E10' now) I have occasionally found float needles get sticky if you leave things for a week or so. Whether this is true cause and effect or just paranoia, I don't know.

[Ian]

Proper BSA - Brilliant Studious Advice 😜
I had two spark plugs expire in short succession and smelt a rat but maybe I'm being unfair to rats. Initially it was running too rich but now golden brown.
No speed demon just cruisin for a brusin