Sporton
Details
The
frame is a replica Norton featherbed. No actual Nortons
were harmed in the making of this sidecar. Originally it housed two 650 Triumph
engines and was raced by Robert Glock. I purchased
the frame from him (Thanks Bobby) and proceeded to slice 6 inches from the
middle of the frame. The welding work was handled by Mr
Rob Olsen from Emu Products, one of the finest
fabricators I know. Thanks Rob.
The
front end is a leading link item with adjustment for trail. I have a set of Koni's on the the bike now to
handle the springing duties.
The
rear end is conventional although I have kept the fabricated swing arm that
came with the frame and it's mounted behind the frame tubes rather than in the
front of them.
The
rear engine mount was fabricated for me by a local company and is simple being
little more than a "C" section of mild steel, drilled to suit the
stock Sportster rear motor mount and welded to exisiting
tubes on the Featherbed frame.
The
third wheel is an alloy mini item running on a hub with tapered bearings and
mini stud pattern I picked up new from a trailer shop
The
Engine
The
engine is basically a 1957 XL Sportster 883cc 4 stroke V-Twin. There are a
number of modifications that I have made to provide a bit more power and
reliability.
The
cases themselves required only a collar being machined up and welded in place
to protect the countershaft bearing boss in the right case half. Other than
running a tap through the screw/bolt holes and a thorough cleaning nothing else
was required. I did replace the pinion side case race and bearing, transmission
mainshaft case race and left side Timken bearing as a
matter of course.A set of S&S stock stroke
flywheels and S&S Super duty rods have replaced stock items. Stock
Sportster flywheels are cast iron and have been known to explode in racing use.
Sitting
on top of the S&S rods are keith
Black moly coated pistons. A 30 thou overbore brought
the stock cylinders upto scratch. Static compression
will be about 10 to 1.
The
heads as everybody knows are where the power is made (or not, as the case may
be). The heads have a port job, new guides and XLR inlet valves and stainless
exhausts. Down below I have a set of Sifton's
Scorpion camshafts to help with the breathing. Just at the moment I have a set
of S&S push rods although these may be discarded in favour
of chrome moly ones which might be both stiffer and
lighter.
I
have been able to get an S&S "Super B" carb
passed by MA as suitable for Period 3 use and that's what's on there now. I
also have a set of Strociek roller rockers although
these are second hand and were damaged. PLR
Engineering have taken on the task of sorting them out
for me and will go on when they're restored.
Ignition
is a Mert Lawill single
fire distributor although I just recieved a Mallort Electronic system with Dyna
coils and will install this when time permits.
The
transmission has been totally re-built with a mixture of Andrews and HD XLR
gears and shafts to produce an "N" ratio which I am hoping will be
good for an outfit. A stock XLR 30 tooth sprocket and triplex change will drive
a stock 900cc dry clutch and I am hopefull that will
give me an overall ratio sufficently high enough to
make the outfit accelerate in a respectable manner. (Bat outta
hell I hope)
Note: The close ratio box was NBG !
Managed to destroy itself in short order and the change from 3rd to 4th was
only a 500 RPM drop. I've since gone back to stock ratios and Stanthorpe (Carnell Raceway) ptoved
it to be a much better option.