The Knowledge - Velocette Owners Club

it, fit a 86mm cam steady plate with the cam oiling jet. This will involve silver soldering a boss onto the
existing timing cover feed pipe and drilling into the pipe, not the easiest of jobs. If originality isn’t
important use a Venom / Viper timing cover and save yourself all the extra work. If you have a
crankcase with the rear cylinder oiling jet you can blank this off by using an ordinary bolt, rather than
the oil feed bolt. Then drill two small holes the same size as those found in the cam oiling jet in the feed
to the back to the cylinder – this is tricky to get them at exactly the correct angle to spray oil onto the
cams. Finally silver solder two one eighth inch bore pipes near to the bottom of each of the valve spring
cups to help drain the oil away. Use of flexible tube to connect this to a Venom type pushrod tube.
Finally buy a copy of Phil Irving’s book “Tuning for Speed”, it’s packed with practical and useful
information. Perhaps some of the MAC racers in the group can comment or add to my note May be
vibrations or force makes to flax the crank shaft? What I think is, primarily chain sprocket have to be
run as close as crank centre to reduce effective distance of shaft. This mean sprocket as close as
crankcase? The end of shaft there is a shock absorber. I think they have to go as they are hanging a
lot! This mean have to use rear hub like Triumph (with absorber inside) or convert to the primarily belt
drive?
L #257 1961 Venom with fairing and 3.9:1 top gear = 110-112 mph Standard Venom top gear
ratio 4.9:1 = 96 mph.
L #560 I got a 58 Venom since two years now and try to get it to its 100 MPH told capacity. By
now, the Lucas Racing magneto has been overhauled and the carburettor is a new Amal Monobloc
(checked and re-checked by my workshop), fitted with a 330 main jet. Test after test, the engine is very
smooth, but the power "flattens" when reaching 75/80 MPH with only 3/4 throttle with some impressive
vibration. Looking for any possible reason, I would like to know if this 100 MPH performance can be
reach with the standard 18 teeth sprocket, or if I need to fit a 19 or 20 teeth sprocket in order to be able
(may be) to get the bike to 160 km/h ? Regarding the vibration, may be the wheel chain tension is too
high, and I will correct that as soon as I got time. Another question is that it seems that the engine oil is
"jettisoned" through the oil breather tube. I got a recovery bottle (half a litter), fitted with its own breather
tube facing the road to limit the spillage. What is interesting is that the bottle is full after 300 or 400 km,
but when oil drops comes out of the forward outlet tube, the oil consumption is then ridiculous. I had in
the past a Ducati Darmah. In the oil breather line, there was a restrictor dedicated to prevent the oil
breather to act as a jet pump (or a jettison as we call in my job). Does the oil breather adaptor
mentioned in the Velocette Parts List contain a restriction or shall I fabricate one in order to be sure that
only oil "smoke" only goes through the breather line ? The fact that oil consumption comes back to
normal figures when the bottle is full tends me to think I shall.
#566 You will need minimum 19 tooth sprocket, or an enormous rear tyre with an 18 tooth sprocket to
pull the ton on your Venom, assuming 6200 rpm rev limit. For an Avon 100/90x19" rear tyre gearing
charts show these speeds per 1000 rpm and maximum speeds in top gear for the commonly used
gearbox sprockets. All speeds quoted are mph: 18 T 15.389 95.412 At 6200 rpm 19 T 16.244 100.713
At 6200 rpm 20 T 17.099 106.014 At 6200 rpm 21 T 17.954 111.315 At 6200 rpm
#567 Earlier posts discussed top speed of a standard Venom and in my opinion a well set up Venom
with the rider sitting upright will do about 85 mph + - 5 mph. The 100 mph in past road tests, were when
riders were flat on the tank. Why? Due to the petrol now available, most Venoms have to run with
compression ratios of 8;1 rather than the 8.75: 1, which reduces the power by approximately 2 BHP.
Amals tell me that a TT carbs only flows 3% better than a Monobloc so it’s not that. Finally I think as
riders we are all presenting greater wind and frictional resistance as a result of maturing! How can you
make it go faster? Apart from setting the engine und the rest of the bike up well, short of fitting a
Thruxton head, probably you could get your Venom head gas flowed. Has anyone noticed that some
Venom heads are stamped G or OK on the cylinder face, anyone know what this means? You could
also fit a spacer between the carbs and head to get the induction pipe length to resonate at somewhere
between 5-6000 RPM (if you have room between engine and oil tank). Lightening the valve gear will
only really allow you to rev quicker and safer. The M17/8 is the best readily available cam around. Even
at 85 mph a Venom does not normally vibrate to any noticeable degree. Check the following Head
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