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DCM Special breaks ground
How's this for a tasty contender for club bike of the year at the 2006 rally...
"DCM" stands for Dave Camier Motorcycles and he's based in Kent, UK. The frame
on my bike is actually a JCM (James Camier Motorcycles) and resulted from an
earlier business hook-up between Dave and this bloke James. I call my bike a DCM
as there were hardly any JCMs made and they were identical anyway.
Unfortunately, James passed away in his 30s shortly after the partnership
started and everything changed to DCM.
Dave Camier used to race Formula 1 bikes and endurance racers. His son, Leon,
was the 2005 British Supersport champion riding a Honda.
JCM frames were originally sold through Maitland Racing in the UK. My frame was
originally imported by Barry Murfett from Maldon in Victoria. It was in kit form
and comprised of the frame, swing arm and alloy tank. Barry turned it into a
café racer and it saw action on Victoria's roads until I acquired it. The
original bikes were monoshocks designed to take Yamaha TZ engines. Mine's a
monoshock frame as well but is a little different in that it has no fixed peg
mounts.
The bike has a set of TZ forks and triple clamps on it with an RD slide on one
side to take the brake caliper. It's an ugly arrangement and I'm going to try to
get an AP Racing twin piston caliper. They're about $600 though and I really
need to borrow one first so that I can check spoke clearance. The front wheel is
an orphan, possibly a Brit aftermarket one. Does anyone recognize it? The front
guard is genuine TZ alloy. I fitted the rear wheel myself: it's a TZ/TR item. I
also made the rearset plates and pegs but used the original rear brake and shift
levers it came with. The rear cable system is also a Stewie Ross creation. The
clip-ons are Tingates and the clutch and decompressor lever assembly is YZF
pattern.
The tank had some serious dents and ugliness to it and I had Bernie (the
magician) Willet fix it up. He is a very skilled guy who lives at Research and
who can make anything out of alloy sheet. Among other things, Bernie used to
make the tanks used on the Harley-Davidson XR750 flat-trackers.
The seat is from a TZ (D) pattern which has been painted but is yet to be
upholstered. I'm fitting a half-fairing to it (like the smaller version of the
Ducati SS fairing on my black café racer). I have also fitted an alloy breather
tank up under the seat. This was welded up by the aforementioned Bernie from a
cardboard pattern I sent him. The oil tank resides beneath the engine and may be
in for some modification at some stage. The DCM types were shorter and deeper,
and away from the rear wheel.
The story continues - I have yet to finish the bike and I'll be using it as a
track bike for "play racing" (not at a track!) when it's nice and quiet (heh,
heh...)
Stu Ross
TINGATE SR REVEALED
Melbourne-based bike
guru Rod Tingate has made various bits for SRs for many years. Put all the bits
together and you have a Tingate 500 – Grant Roff has one and he suspects,
apart from Rod’s own bike, it might be the only one left…
It’s hard to get to
the bottom of the Tingate 500 story. Rod Tingate always believed that simple is
best and in the time he could save from making race bits for Australia’s top
teams he created his own 500. This included making an alloy tank and a
fibreglass seat and tail section, giving the bike its distinctive appearance.
Legend has it that Rod
built his bike just for one bit of road – the famed Reefton Spur just out of
Melbourne. Rod cleaned up just about everyone he rode with, creating a demand
among his friends for a similar bike. He built possibly half a dozen tank/seat
sets but became frustrated as they sat around for years in sheds as unfinished
projects. In the meantime, he continued to produce rear-sets, clip-ons and grind
the occasional cam for interested customers.
Mick Hone, former road
racer and now proprietor of a giant Suzuki dealership in Victoria, is suspicious
of how good a Tingate 500 actually is, claiming Rod was a rider of such
exceptional ability that he could have beaten his mates on a pushbike.
Another of Rod’s
friends, Peter Jones (then state service manager for Yamaha) acquired the bits
and actually finished the project, resulting in the bike you see on these pages.
The finished bike sat
under a sheet at the back of the Yamaha warehouse in Victoria and managed to
cover just 300km in five years. Everytime I visited the factory I pestered Peter
about buying it until finally he cracked. It now has around 10,000km on the
odometer and is regularly sighted on fine days in the Dandenong Ranges.
What’s in it?
While Rod is
responsible for the bike’s overall appearance, Peter introduced some unique
features. He started with a bare SR frame and cut off all the unnecessary bits
(including the centrestand and mounting lugs. All over the bike is evidence of
Peter’s desire to save weight. The wheels are 18”, seven spokers from (I
think) the humble XS250 but Peter cut the middle out of each spoke, creating a
far lighter 14-spoke design.
The front and rear
discs are drilled and the fork legs have been turned to reduce their diameter. A
hand-made, lightweight fork brace keeps the forks apart and air caps have also
been fitted. High-rise Tingate clip-ons complete the front end which, along with
the increased height of the rear (repositioning the lower mounting point for the
rear Konis closer to the swingarm pivot) provides sensational ergonomics for
riders six foot or over.
Club pres, Chris
Manhal, has ridden the bike and his first impression was of how big it feels. A
happy side effect of this set-up is increased cornering clearance.
The tank/seat
combination speaks for itself and, although Rod has said he feels it might be
starting to look a bit dated, many observers reckon it’s the world’s
prettiest bike.
Other technical
features include an underslung rear brake caliper and braided brake lines.
The driveline is from
a TT500 and Peter went down this path to reduce the drag of the original chain
and sprockets. The TT stuff is lighter and thinner but more than capable of
handling the SR’s modest power.
Engine mods
Peter basically stuck
with stock bits because he valued reliability and service life over extra
performance. The engine was lovingly put together, though, and the flywheels
were machined down to TT-specs (narrower and lighter) which allows the engine to
rev more freely. A fruity note is provided by the Tingate exhaust and the engine
breathes a little easier with a K&N air filter.
So how does it go?
Engine-wise, the
Tingate is a bit faster than a stock SR although it appears much faster on the
road because the bike is so light. Rod’s own bike has (again, I think) a 38mm
flat-slide carb and having experienced Chris Manhal’s bike, the bigger carb
would make a substantial difference and get the most from the exhaust system.
Another club member, David Morley, has a Tingate cam in an engine sitting on his
workbench which is also a bit tempting.
The light weight and
18 inch wheels allow the bike to be thrown from side to side easily and the
additional cornering clearance can be well used. Peter Jones had Michelins
fitted when I acquired the bike but they were skittish possibly because they’d
gone hard through not being used but also possibly because the bike is so light
I couldn’t get them to heat up properly. These were replaced by Dunlop K81s
and I can’t speak highly enough about their performance. Retaining the
original rim size was deliberate as both Peter and Rod believe the narrow tyres
work better. Such is Rod’s commitment to narrow tyres and rims on SRs that he
runs a front tyre on the rear of his bike. The
handling isn’t perfect yet, though. The springs on the Konis feel a bit too
stiff and a light steering damper is also on the shopping list.
If you’d like to see
the real thing, come to the first SR500 Club rally announced on page one. If
you’d like a taste of Tingate gear, the secretary (Paul) is selling Tingate
clip-ons for $110 a pair (see classifieds).
Thanks for the style,
Rod, and thank you, Peter Jones, for all the hard work.
CLUB WISDOM
Almost none of what
appears below my be technically true, but it’s the result of a spirited,
round-table discussion held at the SR Club’s last meeting. The question is who
do you believe?
- Lubricants
At a minimum, SR
engines should get a 20W40. Shell Helix 20W50 got a couple of raves but also a
few negative comments based on how bad Shell XMO was when it was released and
some negative experiences with Shell Advance.
Out of left field,
Motul 3100/3000 was praised by resident wrecker, Andy Bremner, and there was
general agreement that Penrite HPR 30 (or 40 or 50 for that matter, depending on
whether it’s summer or winter) was a reliable performer. Spannerman likes
Castrol GP but there was some criticism of this product related to experiences
of foaming.
Almost nobody thought
synthetic oils had any real advantages for SR engines. Oil
change periods also varied with the lowest being 2000km and the highest being
never – although that particular bike features a constant loss lubrication
system meaning any oil in it is almost always fresh. There were some raps for
5000km although all agreed it depends on how you use your bike. If you ride flat
out in hot conditions or if you just make short trips without the engine ever
really reaching its normal operating temperature, change the oil closer to the
2000km end of the spectrum.
- Petrol
There are over 100
members of the SR500 Club and every bike engine is in a slightly different state
of tune. There was a consensus view that lead replacement petrol (LRP) was crap
– basically standard unleaded with the addition of some valve-seat lubricants
which, unlike lead, don’t combust well. The result is harder starting and
rougher cold idling, but, for low compression engines, there wasn’t much
evidence of pinging when the engine was at its normal operating temperature.
Everyone loves the
premium unleadeds, Mobil 8000 works well for me.
- Tyres
There were a
surprising number of 18-inch front wheels fitted to bikes whose owners were
participating in this discussion. This gives a bigger range of tyre choices.
Dunlop K81-style TT100 Roadmasters are probably the stickiest but not everyone
would be happy with 3500 – 5000km from a rear tyre.
Metzeler ME33 fronts
were a favourite and Bridgestone Battlax BT45s were promoted as offering good
grip and a service life of up to 15,000km.
Another long laster
with good, all-round performance was the Barracutta range.
Avon Supervenoms were
recommended for 18-inch combinations.
- Miscellaneous
-
Early model
stators can advance themselves and burn pistons. Later models can be
retro-fitted and are more reliable
-
If you have a
drum-brake rear end, the length of the actuating rod is exactly the length
of the rear shocks, meaning if you brake a shock on a trip you can limp home
without a rear brake but also without the rear wheel wearing through the
mudguard.
-
Stators and rotors
are matched, meaning swapping them around between bikes will give unreliable
results.
-
If you break a
throttle cable, you can limp home by replacing it with the throttle return
cable.
THE
PORSCHE OPTION
SR owners can improve
the performance of their engines, reduce mechanical noise and claim a
relationship with Porsche engineering for less than $100. Here’s how…
Valve clearances for
the SR engine are set by simple screw adjusters with lock-nuts. While this
system is simple and effective, it has some disadvantages. The contact patch on
the adjusters is relatively small and, even with properly set clearances, the
top of the valve stem is pounded without mercy in use.
The adjusters used in
Porsche engines (p/n 90110537002)
have a flexible cap at the end of the adjuster which fills up with oil and and
keeps the adjuster in constant contact with the top of the valve stem. This
means no tappet noise and minimal hard contact between the adjuster and the
valve. Fitting
the Porsche adjusters does require a bit of machining work but no precision is
required. You can do it with an angle grinder, a hacksaw and an old school
ruler.
The Porsche adjuster is
a bit longer than the stock adjuster so you need to cut the top off it so it’s
the same length. Use the same hacksaw to then cut a slot into the top of the
adjuster so you can turn it with a screwdriver. You
then need to grind about 4mm off the end of the follower where the adjuster is
located. The reason precision isn’t necessary here is that all fine
adjustments are made by the adjuster itself when it’s in place.
It’s important to
note, though, that, unlike the stock item, you need to fit the adjuster to the
follower before you put the followers back into the head. The stock items can be
screwed in and out with the followers fitted but the cap on the end of the
Porsche adjuster prevents this. It’s no big deal as you had to remove the
follower anyway to do the small bit of grinding. In
case the amount of metal you take off the follower concerns you, the Club
president’s bike has run this modification for around seven years without
complications.
One last thing to
consider is the follower itself. The followers fitted to the very late model
SR400s from Japan have different oil passageways for lubrication and would seem
to offer better protection and lubrication at the camshaft end. While the top
end is apart, it might be worth considering a swap.
GEARING
A popular conversion
for SR500 owners is use TT/XT drive components instead of the stock SR items.
A stock SR has a 530
chain and a 46/16 rear/front sprocket setup. This is fine for short, city work
and the chain lasts well but the gearing is too low for long trips. Riders are
often looking at 5000rpm-plus at legal limits.
The trail 500s used a
520 chain which provides less drag (more power and better mpg, but it would be
difficult to measure!) and a wider range of sprocket sizes.
According to club
member Andy from Vicwreckers, sprockets that will fit the SR rang, in the rear,
from 40 to 53 tooth. Front sprockets range from 13 to 19, although 17 seems to
be the biggest front sprocket you can run without having to modify the outer
cases.
A larger front
sprocket will raise the gearing (less revs for more road speed) and a smaller
rear sprocket will do the same. The opposite is also true - an SR with a 13
tooth front sprocket and a 53 tooth rear would have a top speed of around
60km/h, but you'd get there quickly!
Presuming your engine
is okay, it will pull a 40 rear, 17 front comfortably, and you'll be able to
loaf along the highway at legal limits without wearing your engine out.
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