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Being a little unsure as to the set up of a
left hand drive outfit I looked in the old club magazines for
clues but there are precious few, tons for right hand drive but
virtually nothing for left hand drive. I set it up with 10mm toe
in on the sidecar with the bike leaning away `a bit' as a
starting point. It seemed fine when I went for the MOT, I went a
long way round to take in all sorts of roads. In fact it felt
good.
Later, much later actually, after winter but
that's another story, I was going out of the village when more
or less without warning the outfit went left off the road onto
the grass verge towards a ditch. Happily, at that very point the
grass verge ended and the pavement started so I steered back
onto the road. It felt for all the world like a rear tyre
puncture, but it wasn't. I carried on, feeling a little nervous
of course. All was well for a while but coming into the village
from another direction one day it happened again. Luck was again
with me as the dry stone wall I was heading for ended so back
onto the road I steered and without stopping carried on home. On
reflection, both instances occurred because the sidecar wheel
hit a bump in the road. However, I journeyed to a local vehicle
show one Saturday and used all the back roads, which should have
been enjoyable but was certainly not. It felt like being on
roller skates on a 30-degree slope in a strong wind, on ice.
30mph was the maximum believe me!
Drastic action called for. Past experience
with left hand sidecars showed that solo they were great, but
put a passenger in and the whole plot leans the wrong way and
starts:
Breaking rear wheel spokes.
Pulling to the right all the time; to the
extent of the right hand twist grip rubber coming off!
ANSWER: Spring the body, not the
chassis. This I now did on my right hand chassis, replacing the
suspension unit with an adjustable link. I have set it so that I
can just remove the wheel without it fouling the mudguard. Next,
set the bike so that with me sitting on it, the bike is
vertical. The outfit is now absolutely marvelous, an
unbelievable transformation. With a passenger (Not easy to find
with a right hand chair) the handling is the same as riding
solo.
Looking again through old C.O.C. magazines
(From the 1970s) I came across a letter from a club member
saying that the handling of his outfit with right hand chair was
transformed when he reset the whole plot with the bike vertical
with him sitting on it. The answer is out there somewhere
whatever the problem!
The bike was running well but only with the
air restrictor, or choke if you prefer, half closed. With it
fully open you could not start the bike at all and if it did it
would not run. As the bike was needed every day fiddling time
was up for a while. The months went by during which I bought an
electronic ignition kit from 'Boyer Bransden' but didn't fit
because the bike was in more or less constant use.
However, events gave a window of time where I
could start fiddling again even though the bike was running well
and starting first time every time. The first job was to fit the
ignition and prove that it was set to the correct settings by
using the bike for a week or so before working on the
carburettors. Remember the golden rule; alter one thing at a
time!
I modified the mounting plate for the points
and condenser in the early 1990s and considering the mileage I
must have done since then the points were the same set and
looked quite good! But with electronic ignition, timing will not
need checking again which is good considering access is not
exactly easy!
By the way, a hint to setting up the timing
on the Boyer unit. It seems that on a standard installation
(British bikes) the stator is in front of the rotor. On the Ural
the rotor is in front of the stator so even though the camshaft
rotates anticlockwise you set the Boyer unit up via the
clockwise timing mark. Confused? No need to be, quite simply the
correct timing mark is the one before the inductive pick up
(Going anticlockwise remember) coinciding with the fully
advanced mark on the flywheel.
Back to the carburettors. Even with good
running it was obvious that one cylinder was running quite rich
while the other was quite weak. The rich one had the needle
fully down but was still rich while the weak one had the needle
fully up to make it richer but it was still a bit too weak. Are
you following this?
First job, check the petrol levels in the
float chambers by removing the top and the float, having made
sure beforehand that the carburettors were in 'running'
condition. The level in the rich carb was 6mm higher than in the
weak carb! That is a lot. I was using a set of vernier callipers
with a depth gauge on the end so I could be a bit accurate! The
obvious next job is to check the brass floats for leaks, no
problem there. So using a set of Weight Watchers kitchen scales
(I knew I would find a use for them) I weighed the floats. The
'rich' one was 12 grams and the weak one was 9 grams! No wonder
the petrol levels were differing by 6mm. It looks as though in
the past someone had repaired the heavier float but of course
solder is heavy, hence the difference.
Sorting through my assorted bits of
carburettors I found two plastic floats from K38 carbs but
overall they were shorter but could be made useable by using the
K38 float chamber tops. Are you still following this?
The levels in the float chambers were now
equal. Relative to 'official' level of petrol they may be a
little out but not that much compared with the situation before.
Next job
Check the needles. These were as originally
found in the carbs but I thought I would check them again.
Needles are not easy to check as I found out last year.
Measuring the diameter every 3mm or so and doing exactly the
same with another needle and comparing the results needs better
equipment than I have. However, as a go / no go comparison the
following procedure works well. Mount the vernier callipers in
the vice, lightly! (If you have three hands ignore this bit)
Set the callipers so that a needle will go
through the parallel faces by 3mm. Then push the other needle
alongside. They should stick out the other side by an equal
amount. Then open out the callipers a touch more and try again.
At all points the needles should stick out the other side by the
same amount. Mine didn't! You can be correct in thinking that
the rich carb needle was thinner than the weak one. Having found
the floats to be different I was not expecting this at all!
I considered the chances of finding another
K301 needle in my swag box to be a very remote possibility but
the luck that deserts me in respect of the lottery and premium
bonds was with me that day! Hiding under much grime was a needle
that compared perfectly with the 'weak' needle. I am still
trying to figure out where on earth it came from but I will not
loose sleep over it.
The problem with altering carb settings on a
motorcycle is the probability that the starting sequence will be
different and a long learning curve lies ahead. Before part two
of setting the K301s, the sequence was to turn on the petrol,
flood the two carbs, turn on the ignition and one kick on the
starter would have the bike going (Remember, of course, that the
choke was half shut permanently) Cutting a long learning curve
story short the sequence is now to shut the choke fully, turn on
the petrol, flood both carbs, turn on the ignition, one kick
will start the bike and then open the choke fully. I can almost
believe this is how it is supposed to be!
(This ritual of starting bikes and cars based on early
technology reminds me of the even worse ritual of flushing the
old style toilets with the cistern mounted near the ceiling with
a chain hanging down ending with a polished handle grasped in
the foolish hope of achieving a first time flush. Many times
these were outside, yes I am that old, with no electric light to
add to ones coming woes. One short pull followed by a long one
exactly two seconds later, or was it one long pull followed by
two short ones? Every one was different and you could be trying
for what seemed like hours trying to understand the mystery.
Meanwhile panic was rising in that the resident spiders in such
unspeakable outbuildings were about to pounce. Breaking the
Enigma code must have seemed a doddle compared to flushing the
bog) [ED: I believe that they were flushed with success!]
There are times when progress is a wonderful
thing!
Anyway, back to the future. How does the bike
run? Very well, it seems a lot smoother at 40 to 50 mph and
sounds more subdued and 'happier'. All in all, a worth while
exercise.
A bit for the newsletter / HV: In the Popular
Flying Association Magazine (A magazine for builders and flyers
of homebuild aircraft) one of the professional inspecting
engineers uses 'Pledge' aerosol polish on 'perspex' [Ed: a type
of acrylic] windscreens. It seems that not only does it build up
scratch resistance but also polishes out existing scratches over
time! My bike screen was looking a bit 'milky' but 'pledge' is
improving it slowly but surely. Remember where you read this tip
first!
Phil
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