Author Topic: Recomended Spark Plugs for 1949 Star Twin?  (Read 1056 times)

Offline LJ.

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Recomended Spark Plugs for 1949 Star Twin?
« on: 09.11. 2008 09:19 »
I'm needing a little help here guys, My three week old Star Twin is being a bit of a pig to start at times, I'm sure the plugs it has are not correct, Champion L10.

I know full well how fussy my A10s are concerning plugs, they currantly are using NGK BP6HS even my M21 has to have exactly the correct plug or it'll moan. I found the A10 plugs not satisfactory for the Star Twin. (To my suprise)

What seems to be happening is that the throttle has to be opened right up wide and it will then likely start with a very lumpy running, sort of like its very rich, but I have checked that the choke is off, I know that the carb is clean as it was stripped right down a week or two ago the plugs centre ceramic is a good colour. It might just be the air filter that could be clogged up, so I took this out last night and really I should be asking for help after I run the bike this morning to see if any improvement is made. I'm pretty much sure that the magneto is Okay, bike will start and sometimes start very easily when its hot. So I need to be sure from other Star Twin owners that I have the correct plugs. Jeff? BezaBill?
Ride Safely Lads! LJ.
**********************
1940 BSA M20 500cc Girder/Rigid- (SOLD)
1947 BSA M21 600cc Girder/Rigid-Green
1949 BSA A7   500cc Girder/Plunger Star Twin-(SOLD)
1953 BSA B33  500cc Teles/Plunger-Maroon
1961 BSA A10  650cc Golden Flash-Blue
1961 BSA A10  650cc Golden Flash-Red

Offline jfligg

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Re: Recomended Spark Plugs for 1949 Star Twin?
« Reply #1 on: 09.11. 2008 13:39 »
Hi LJ
       I use NGK B6HSin my bike for the last 4 years.  Are there pictures of your bike on here?  Did you find a twin carb manafold.  How does the plug leads and the mag slip ring look?  I hope this helps.  Jeff
  P.S I just read the link to your A7 story.  Very Cool.  Sounds like fouled plugs. 

Offline LJ.

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Re: Recomended Spark Plugs for 1949 Star Twin?
« Reply #2 on: 09.11. 2008 17:34 »
Hi Jeff... Thanks for the reply, Yes there are a couple of Pictures of my Star Twin on another thread
http://www.a7a10.net/forum/index.php?topic=49.0

They are of the bike when I had just off loaded her from the trailer and before I did anything to it. Done a lot since then and have put an attached photo at the bottom of this message, its difficult to see the work done from photos. The main thing at the moment is getting it running properly before I go to the work of repainting the awful shoddy paint scheme on the tank, the mudguards are not much better even after a good 'T' cutting down, the whole bike had been brush painted, looks very original and authentic mind, but I'm not so comfy with it like it is. Springtime or early summer and i'll have the spray gun out.

Well most of the day I was out on the BSA M21 but managed to get an hour on the Star Twin before it got too dark. It ran fine, started up okay after a stop to take the photo that you see below. I'll need more stop & starts before I'm any happier and will consider the plugs you mention NGK B6HS. I saw at a mates this afternoon, looking through the Roy Bacon Book 'Twins & Triples' that the NGK B6HS is recommended in the specifications. Blimey! I'm knackered now after all this, that cold wind today while riding will knock me out in front of the fire this evening!
cheers!
LJ.
Ride Safely Lads! LJ.
**********************
1940 BSA M20 500cc Girder/Rigid- (SOLD)
1947 BSA M21 600cc Girder/Rigid-Green
1949 BSA A7   500cc Girder/Plunger Star Twin-(SOLD)
1953 BSA B33  500cc Teles/Plunger-Maroon
1961 BSA A10  650cc Golden Flash-Blue
1961 BSA A10  650cc Golden Flash-Red