The Knowledge - Velocette Owners Club

L #3777 My 1938 MSS has an old AMAL 276, with the remote float. It has been running a bit off
for the last 500 miles or so. The bike will run fine when opening the throttle from idle through wide
open. But if I hold the bike at 3/4 throttle, it will cough every 2-3 seconds. If I open the throttle a bit
more, the bike runs great. On my last two rides, I've just kept the throttle opened a bit more, or a bit
less, than the trouble spot, and everything has been fine. I'm guessing that the slide is slowly wearing
out, but shouldn't that affect the carburation at lower rpm levels? Maybe the needle jet is wearing out... I
guess I'll pull it apart and look inside.
#3779 It's quite possible the slide is worn after many years - you can bore out the body and re-bush,
but it's a fiddly business. Before that I'd take it apart and clean out thoroughly - try the easy things first.
Is there a leak on the carbs flange joint -? this would affect slow running worst. Needle worn - probably
the jet it runs in is more likely . The fact that it's only happened in the last 500 miles suggests a
blockage etc rather than wear which would take many 1000's of miles to show up, and happen so
slowly you'd hardly notice.
L #4281 Hello all, this past weekend was the first shakedown run for the new MAC on our fall club
ride. Things didn't go too well. After getting about 10 miles from home, at an intersection, it quit and
refused to start again. After waiting for about 20 minutes it did start, and I continued, but it wasn't
running very well. The further up the canyon I went the worse it ran. It seems to run really well as long
as the road is flat and I don't push it too hard. Does this sound like a magneto problem? Does anyone
know about Kirby Rowbotham engineering in England that offers an electronic ignition conversion
inside the existing magneto? Coming down the canyon it was backfiring and spluttering all the way. I
think it felt like ignition trouble. Anyone on this list have any thoughts?
#4286 Does it still have the fibre mag wheel? If so check the teeth for wear. I had a problem years ago
where the timing kept altering by itself. I fitted a steel wheel and ran with ignition fully advanced, no
problem with a MAC.
#4282 Poor hot starting is classic magneto trouble. While you could go electronic I'd suggest that you
just get the magneto rewound by a reputable company and it should be fine. I had the same problem
with my 1954 MAC when I first got it and the rewound mag transformed starting and has been good for
8 years now.
#4283 Most likely the magneto, but first make sure the petrol can get into the carbs quickly. I changed
the mag ( which meant lifting the barrel to remove it, and just how are you meant to get to those 3
nuts?) only to find that the tap filters only passed a dribble that run the bike fine until you tried to go
faster!
#4284 Do you have the proper heat proof gasket on the carbs / cylinder head joint? (K180/3). I had
similar problem with poor hot running /starting performance. When I replaced the paper gasket with the
proper one the problem went.
L #4689 I have just purchased a restored 1956 Venom and can't get it to run other than with the
choke open (air slide closed). As this is my first ever Brit Bike ( or indeed any bike that did not run as a
starting point!) I am at a bit of a loss where to start with changing the settings. The previous owner
indicated that the jetting is standard so I am guessing I need to play initially with the pilot air adjusting
screw. Is there such a thing as a standard setting from which I can then twiddle ( similar to the
procedure on my Airhead BMW's Bing Carburettors) ?
#4690 Look at: www.croesus-consultants.co.uk/v-tec (the Group owner’s) and a treasure trove of Velo
info (including carbs settings). For guidance on checking the settings try:
www.hitchcocksmotorcycles.com which has the AMAL hints and tips for setting up your carbs.
#4699 Assuming an Amal Monobloc is fitted. I'm not sure what you mean by choke open/air slide
closed. Choke open usually means the air slide is not obstructing the choke of the carbs (the air slide is
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