|
 This bike was once a totally
complete matching numbers 741. I sold all the bits to builders of stock
bikes and created a stroker racer. I had no qualms on doing this as it got
the last needed hard to get bits for six other bikes. It also financed my
purchase and a large proportion of the development cost. The costs in
money were not great as apart from chroming and casting, I do all work
myself. I had new heads cast in a superior alloy as I wanted
to change plug angles and run the domed pistons, a little more than
1/2 into the heads. My heads have an extra horizontal fin if you look
close. I looked at all the available WL series crank
assemblies and rods etc. and discarded them as too expensive or just plain
worn out. I got given a fairly late model sportster flywheel set and found
some iron head sportster 1000 cc rods. I went with the H/D drive side
bearing set up as it is very strong. I bored the 741 cylinders to 70 mm
and wound up with 735 cc, which is a shade under
45 inches.  The bike proved fast and
bullet proof in several seasons of classic racing on both short and long
circuits. It was originally destined for a trip to Daytona , but in the
end we only sent two members as I had to pull out for family reasons. Our
boys Paul and Brent, did quite well for themselves, all things considered.
Here in New Zealand the classic scene is very much British based and the
club got a bit peed off when these lowly army Indians as they are known
here, started nipping at the heels of the Norton Manx's! As a result they
started making it difficult in scrutineering and other ways. I went back
into racing for fun, not politics, so have converted this bike back to a
bobber of sorts. The only detuning I have done is to take out the Shunk
cams, so it still is good for around 100 mph and is less of a handful.
The exhaust is one of my sand bent tube varieties and makes less peaky
power than the separate tubes we mainly used in racing. It is also
slightly quieter, though not something you would go past a trooper at full
noise. Apart from its wheel standing antics for the unwary, it is a
good loner bike for visitors until I decide if they should ride my
other Indians. The fenders I used are from the local Japanese bike wrecker
so tanks apart, there is not much to wreck. The tail lamp is one I
fabricated up from a few scraps of steel from the off cut box. Battery box
is one I fashioned up to fill the hole and look right. It holds a good
size 12 volt battery and room for a few tools. The pump is a ground down
cast iron one, with a welded on flange mount for the magneto.
If you look back through VI files you will see photographs previous
evolutions of this bike and perhaps more on the How to do bits under the
handle of Firedog. The bike is for sale as I have an original paint 101 to
do an internal refurbishment to. I probably have enough bikes already and
would sell this one as long as it is hassle free. I have
hosted various VI'ers when they have visited New Zealand and keep contact
with them.
The Akront rims, brake mods and various other things keep it light and
make it look like it does the business. My riding bud was the professor of
industrial design at a Philadelphia university and he rather likes it too.
There is no generator, but with a little fiddling I think it could be
achieved. I have kept the bulb sizes small and the battery reasonably big.
This gave me enough light to get home. Let's face it we mostly do not ride
these oldies much at night. I have other bikes with big bright lights if I
want to do any serious night riding. There is a bit of trickery inside the
case. A very meaty flange and lockring made of 4340 steel to carry the
drive side bearing assembly. I left the sleeve a little over length as a
safety measure for the cases. This could be trimmed back to reveal the
Sportster spline-cut driveside mainshaft . That would be the basis of a
drive for an alternator belt/chain, or indeed a small stator. Dave
Blackwell was the first to build a 741 racer. He bored his first cylinders
out to 73 mm and is remembered for a spectacular blow up whilst racing.
After that we only bored 741 cylinders to 70 mm. Some of us fabricate
extra and heavier engine braces which improve chassis dynamics and lessen
the possibility of cylinder failure. Sport Scout cylinders are an option
for those who have them available. The best breathing cylinders are in
fact 841, although these are somewhat harder to obtain. Using WLA or
Sportster stroke with SS or 841 [73mm bore] cylinders puts capacity
above 45 inches which is not an option for C class or New Zealand racing.
Graeme Care is a very fine engineer and has spent a lot of time on
improving the breed and made patterns and had his own design of cylinders
made of superior materials.{ nodular iron] He and I set off down the path
of pistons into the cylinder head, but Graeme has other things going on in
his life and is not racing at present.
The bottom end of the engine is as built about 3 years ago. Bear in mind
the bike has not done a lot of work and the later Sportster bottom end is
more than adequate for the job it is doing in this bike.
Cylinders have been off for a minimal de-glazing hone and new rings
before the last race meet. I gave the valves a quick lick then too and
fitted valve seals to the inlet valve stems. The inlet valve guides are
quite short as they do not pass in to the port area and benefit from using
stem seals. The inlet ports are very large and have been partly filled and
re-profiled to improve flow. There are no inlet nipples present as a
section of thin wall tube has been sweated into the end of the inlet
ports. These are of the same size as the custom made manifold, which is
almost 1.5 inch internal diameter. The carburetor is an M-88 which has had
a total rebuild including all detents, springs, balls and all the normal
stuff. I may have had the number drills out to tickle the passages and
emulsifier tube. From memory fairly standard though. I do remember doing a
lot of fiddling with float height in the early stages. The
pistons I used are GS 850 Suzuki and as such are readily available. I use
a much lower specification piston ring set, hence replacing them recently.
My thinking on that is I might as well wear out rings than cylinders. I
made the valves from suitable Nissan Diesel ones. They are of suitably
high specification and experience has shown me they last very well in both
valve head and stem areas. Exhaust valves are a few thousandths over stock
diameter as there is no benefit to be gained from enlarging. These I made
to restore the seats to as high as possible in the cylinders.
Inlet valves are
somewhat larger than stock. I do not recall exactly where I ended up on
these, but 1 5/16 inch seems to stick in my mind. Safe to say I went as
big as I could get in there and still leave some material in the cylinders
for an overbore on the pistons. Cylinder heads are high grade
heat treated alloy.
They are retained with high spec cap screws and generous hard washers. The
cylinders have been helicoiled as a matter of course. Base flanges were
re-machined as a matter of course. Valves and seat widths are
cut according to modern thinking and back cutting and relief's as
appropriate for best flow. Valve train modifications are restricted to
exhaust lifters to late Bonneville specifications. From memory 1. .39inch
centers, I think[?!] My experience has shown me Indian did not
always get it right on the crankcase cylinder decks. I made a dummy shaft
for the flywheel main shafts and then using this for a datum, skimmed the
cylinder decks, to ensure alignment on all plains and correct
cylinder disposition [ie 42 degrees.] The dummy shaft also proved the
other modifications in the crankcases. The crankcases are set up with a
flywheel scraper and oil dam similar to later Chief practice, except my
scraper runs closer tolerance to the flywheel. The oilpump has
two sealed ball races supporting the magneto drive and this drive sits in
an Oldham coupling which I made for the job. The
Fairbanks- Morse style magneto [ probably a Joe Hunt or similar]
started life as a 45 degree magneto and I have carefully re-profiled it to
42 degrees to get the most even flux to both cylinders. It has a new coil,
points, condenser, bearings, cap and has been re-bushed. At the end of all
this I had the magnet re-magnetized for maximum flux.
The generic parts, such as Morris fit it should they ever be needed.
Morris were helpful with information for re-profiling the cam.
Brakes and hubs: I have skimmed the drums and back plates have
been modified. The drums are ventilated and the front backplate has a
small screened scoop and exit screen. The high friction linings are bonded
and I machined them attached to the back plates to get perfect
profile. The front actuating cam has the profile slightly modified for
more mechanical advantage. The rear backing plate has had quite a lot of
material removed and similarly these shoes were machined attached to the
plate. They may have alloy shoes fitted at present for better heat
dispersal. There are spare unused shoes [
probably originals from memory] that will go with the bike. I
bought Akront rims and I made heavy gauge spokes to suit, from
blanks. Rolled thread form used for strength. Tires are matched Michelin
street /sport type with a reasonably sticky compound and have plenty of
life left in them. I have also put the racing on hold
for reasons I have already mentioned. These days, I tend to get more out
of solving the problems and making the bikes than I do from racing.
Paul Hanes, also a very clever engineer, has been the most consistent
racer , but his is almost 100% sport scout. Paul has featured very well in
the results over the last few years, winning the Pre-war class on
occasion. This class is the equivalent of C class racing in USA. Brent
Symes was the other racer along with Paul Hanes who went to Daytona under
the Indian Team New Zealand banner. All the racers I have mentioned here
were the members of ITNZ We all freely shared ideas and helped each other
without reservation. [No pun intended!] |
