Motorcycle Investor mag Subscribe to our free email news Great Eight The Drysdale experiment (Guy 'Guido' Allen with Ian
Drysdale – July, 2025)
I used
to build my own dirt bikes. Including a Bultaco Pursang
with a bored-out Honda XL350 motor in it. Loved that
bike. I did a lot of flat-track on it, desert raced it,
motocrossed it for a while as well.
![]() And
then I had a thing about two-wheel-drive and still do.
And so I built the Dryvtech hydraulic drive,
two-by-two-by-two (2WD and 2W steering). It was in the
late 1980s that I built that. I had ‘experimental’
written on it because, basically, that's what it was. I
knew it was never going to be outright competitive.
These days I'm working on a two-wheel drive, mechanical
drive. Then
the V8 started off life with two 540 KTM two-stroke
cylinders and heads. Both were on a common crankcase,
but it then morphed into the V8. It was originally a
sidecar racing motor, but they kept changing the rules
all the time and at one stage the rules were a 750cc
capacity limit. But the
sidecar racing market was fairly limited worldwide so
basically I always designed it to be a road bike. I've
only built four of them, so it wasn't that great a
decision! After
that I was in China, working on scooter engines, quad
bikes and all sorts of stuff there for a couple of
companies.
![]() Then
there was the three-wheeler delivery-bike project.
That's a joint venture between an international company
and Stealth Special Vehicles. We built 50
pre-production, not really prototypes, but
pre-production machines. They were tested and some of
them have done well over 20,000km now. We had to do an
average of 8000km, so 400,000km overall. Certainly
towards the end of the trial they were very reliable and
still are.
The V8
project now dates back 28 years! The 750 was based on
two Yamaha FZR400 motors, while the 1000cc version used
FZR600 motors. Really it’s the cylinder heads. I make
much of what’s below the head gasket.
![]() What
sent me down that path? At the time it was a big thing
to have a V8 motorcycle. Morbidelli tried and it sort of
fell over. (Above is the late Giancarlo Morbidelli with
his creation.)
Duncan
Harrington did the design for my project – it looks like
a motorcycle and it’s aged well. It's a little bit like
a Ducati Monster from back in the day, in that it still
looks reasonably current. Duncan
just did an outstanding job on it. He was living in
Sydney at the time, flew down (to Melbourne) on a Friday
night and a week later flew home on the Sunday night. He
did it all in the space of 10 days. Very clever. A 750
revs to 17,000. That's on standard FZR400 conrods and
cams. We could certainly get another couple of thousand
revs out of it with, you know, Carillo rods and hot cams
and stuff in it. The little FZR400 race bikes used to
pull 18, 18.5. The 750 is making 120 horsepower. That
was respectable 28 years ago – very respectable. And it
weighed around 210kg or about on a par with Ducati 916
back in the day. We
originally had carburettors on it and I had two FZR400
ignition boxes on it, with Yamaha FZR400 CV carbies. We
then tried Vance & Hines ignition boxes and Keihin
flat-slide carbs. It just sounded fantastic when it was
idling and just clattering away. Then I
discovered, to my loss, that powder coat is an extremely
good insulator – I just forgot to put the earth from the
battery box down to the engine, so the starter motor was
earthed through the ignition boxes and blew both of them
up. They were sent back to the US where they repaired
free of charge, which is very nice of them.
Then we
went to injection. The thing is that when you're on the
dyno with the flat slides, it was a two-hour-plus
exercise to change the needle height with the
carburettors. You put the fuel injection on it and
basically you don't even switch the engine off. Tap the button
on the computer and, oh yeah, it needs little more
advance there, just a little bit more fuel there. MoTec
was very, very helpful at the time. In all
I built only one 750 and three of the 1000s.
A 1000
revs to 15,000rpm. One example we restricted to 12,500
as it was never going to be used as a track bike, it was
only ever going be used as a road bike. They were making
a solid 150hp. Well
that's enough for a very lively motorcycle. It's a
really sweet thing to ride, the 1000. The 750's a little
bit peaky, the 1000 has just got that more linear
torque. They
run standard Yamaha cams. It's a 200-plus horsepower
engine if you started developing it. You've got 32
valves, you've got eight pistons – it's just an
expensive hobby.
I tried
to get the backing to build a MotoGP V8 when the rules
were open. It got a bit of interest, but no-one was
willing to pay. There were a couple of smaller teams who
were willing to try it if I supplied them with the
engines, but that wasn't an option. Look,
it's basically a calling card for my work in China. They
loved it, particularly because of the V8. So I've got no
regrets for doing it. It's never ever come close to
recouping the money I put into developing it. But, as I
say, it was a good calling card. I think
I gave it my best shot.
Being
there, pressing the flesh, talking to people. And they
actually used it to open the whole show. It’s a huge
thing – we just don't appreciate it. The NEC show goes
for 10 days and there are people three and four deep
around every stand for the entire time. It’s in
Birmingham, which draws people from London, from
Scotland, Netherlands, France – most of Europe. The
Honda stand at that show was three stories high with a
cafe on the top and they built it and then pulled it
down after the event. And you just cannot comprehend
that in Australia. Over the 10 days it was pulling over
2 million people. Just mind-boggling. And I didn't get a
single order and that depressed me a little bit I
suppose.
I would
have liked to have built 10 a year – that would have
kept me more than happy. And these days Brough Superior,
Metisse and people like that build that number every
month. So basically, okay, I'd be a little bit more
expensive than them, but I didn't think that that was
out of the question. And I
just didn't get to the USA. It would have been great to
get to Speed Week in Florida, and those sorts of places
where John Britten made his name. I just didn't have the
resources to do that. After
going to the UK to one of the biggest shows in Europe,
and not getting a single bite, I started to work for
companies in China. You have just got to shrug your
shoulders and go, well, that's that…
Links
Morbidelli
V8 at Motorcycle Specs Other 2WD bikes
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