XR05 MK3, Suzuki TR500 replica
owner of this beautiful TR500 replica was kind enough to send
a whole bunch of pictures of his racer he started to build 30
years ago. Enjoy the photos and read the story at the end of the
Seeley XR05 MK3 is a very close replica to the last of the TR500 twin race machines.
Click on the images for large format. Courtesy of Dave Maskell, the owner.
Steve Tonkin, a former professional TT racer, on Dave's TR500 replica.
The rider's view of instruments notably on left EGT gauge
, front exhaust. Pipes have sensor probes fitted approx. 100 mm
from pistons (see the picture above). This gauge enables rider
to determine exhaust gas temperature at full throttle 1100 degrees
rich... 1200 lean.
Right: Most other rider's view...
Dave Maskell tells:
My Seeley XR05 MK3 is a very close replica
to the last of the works TR500 water-cooled twin race machines.
My connection with the TR500 model began way back at the start
of the 1972 racing season here in England. Colin Seeley started
to produce complete racing chassis to take T500 motor. The first
Suzuki racing frame produced by Seeley finished 3rd in the 1971
TT ridden by Frank Perris for Suzuki GB, also by the legendary
I bought the frame exactly 30 years ago, March 31st 1972. Eddie
Crooks of world-renowned Suzuki specialist "Crook Suzuki
" supplied me with the bike complete less engine for the
sum of £350. The standard new T500 road engine cost a further
£250. Eddie (ex. I.O.M. racer) gave help by replacing new
stock parts in exchange for the much needed racing items e.g.
racing pistons, high comp. heads, close ratio gears, standard
cut primary gears, 34 mm Mikuni race carburetors... plus the help
and advice from non other than race team top man for Suzuki GB,
Mr. Rex White, who I am totally indebted to this day.
Never had anything to do with two strokes let alone racing the
mean machines. It was to be a whole new learning curve thing...
Started of OK at the beginning of the season but was let down
by an ignition system that failed to live up to its name. It would
have been better if it had failed to produce sparks (straight
into the bin). It never failed to produce sparks but sadly at
the wrong time i.e. at full throttle with disastrous results to
both engine and wallet (the cost of this ignition unit then was
£50) so I was reluctant to scrap the damn thing though on
hindsight it would have been cheaper in the long run.
A much used and abused Spanish Femsa of a TZ Yamaha eventually
replaced this unit and it never missed a beat. All our troubles
ended, no more seizures so continued to develop parts to increase
engine performance /reliability that has stood me in good stead
to this day. All the lessons I have learnt have been incorporated
in the water-cooled model.
I must mention at this point in time, the start of the 1973 racing,
I first came in contact with the young (he was then) Steve Tonkin
(thats him sitting on my bike). At that time he was just
starting out on a long and rewarding professional racing career
reaching the dizzy heights of factory rider and developer for
Armstrong, using Rotax engines. He won the 1981 250 cc TT at record
speed etc. and has been a close and valued friend to this day,
for thirty years.
I thank Steve and everyone who has helped with advice and expertise
over this period of time. Their help has enabled me to end up
with the finished product after 30 years as the photos
show, a machine to be really proud to have built and race though
TFFO... too fast for the owner, at least 25 years to late.
The reason that I was able to build the water-cooled Suzuki in
the first place was after reading an advert for works TR500 ignition
Unit complete in MCN (Motorcycle News) late 1989. The guy also
said he had brand new spares for works w/c racer bought from none
other than the famous Barry Sheene. The genuine works XR05 racing
parts were underneath boxes of TR750-3 and RG500 racing spares
he was selling as he was preparing to leave GB for Australia.
I bought up all the parts available so the idea was born.
These were the parts: two barrels (one nicosil plated, the other
steel linered), two heads, six special racing pistons. water pump
and last but not least a very special crankshaft (this is 10 lbs
lighter than my standard T500 crank).
Shorter con-rods are fitted i.e. 130 mm centres, same as the 750-3
kettle road bike.
The crankpins are integral with the inner flywheels so if I run
a big-end I have no spares.
First and the most difficult thing was to modify the top crankcase
half to take the new barrel. Holding down stud configurations
is totally different this means Tig-welding up all stud
holes and filling up with alloy weld transfer port cut-out in
crankcase, (the top case is first bolted down on a flat plate
to stop distortion through heat during the welding process).
After removing from plate after weld completion I was very pleased
to find no distortion had taken place. This was the biggest task
to overcome. The transfer cutaways were machined and the barrel
stud holes jig bored and helicoil thread inserts were fitted to
crankcase, this face was also machined to make sure it was flat
and square to crankshaft.
Completion of assembly was routine, even water pump fits straight
in where oil pump fits, just needed a spacer to clear top case.
Straight-cut primary gears together with
5-speed close ratio plus air-cooled clutch all these were
made by gear specialist Graham Dyson of Nova engineering. These
had all been tried and tested on the old faithful TR.
Only thing is the last 1974 XR05 MK3 were fitted with 6-speed
gear boxes, sadly I only have 5-speed, but on the plus side the
racing unit is fitted in My Seeley frame. A curved radiator taken
from a Suzuki Gamma 250 cc road bike fits neat and completes the
conversion together with updates to Seeley forks and rear shocks,
made by suspension guru Ron Williams of Maxton engineering.
Fast forward to 1999: 16th September 1999 I started my XR05 water
cooled engine for the first time. Note in diary: Sounds terrific!
Cats jumping up trees, dogs hiding under bushes... Fantastic!
Preliminary testing proved that all the hard work was worth it,
my test rider Steve Tonkin came in delighted with all our efforts.
With a little more tweaking it has turned out to be a real rocket
ship. The nearest I am ever going to get a full factory racing
Sadly, the downside is there is no classes over here that we can
race a 20+ year old water-cooled, we can only race with modern
600 fours turning out 120+ bhp at the back wheel... Track days
and several parades by Steve are all we have been too, so at least
the bike is being seen and heard.
I hope this has interested all you Suzuki guys out there. It has
certainly given me much pleasure and satisfaction having completed
my project that started with my first Seeley TR500... this day
31st March 1972 when I took delivery. Thanks to everyone who has
helped with advice etc over the last 30 years. If I can help with
advice on TR500's please E-mail me at this e-mail address.
Dave Maskell, March 31, 2002
Dave lives in UK, on the west
coast of Lancashire, 3 miles from city of Lancaster.
|...and here's an 2006 update
Dave Maskell tells:
Since 2002 we have been out on a couple of parades (sadly because it is water-cooled we can only race against latest 600's). Good news is Steve Tonkin, 1981 TT winner, was invited July 2005 to the Isle of Man Southern 100 50th anniversary celebrations parade — Steve having won the race 30 years ago — three sessions after the days racing, this consisted of three laps; start lap, flying lap and a finishing slowdown lap.
After the first evenings three-lap parade, Steve's first words were 'Bloody Hell, It was not this narrow and bumpy 30 years ago.' He could not keep the front end down.
The following day we had two sessions; 4 pm. after the racing and 6 pm. early evening. Steve suggested we soften the suspension both front & rear to soak-up the bumps. Great! He was all smiles when he came in... He could keep it on line now. Maybe a touch softer on the rear suspension, plug chop showed slight rich on full throttle. EGT readings confirmed this, tailpipes showed dark but dry... Gearing OK... Pulling 10,500 at the fastest straight on the course... Finally adjust rear damping to the softest setting...
Away Steve goes again (I told him to get his finger out). The motor was up to running temp... First lap through start/finish he was mixing it with the big boys. Great stuff; at last we had a yardstick to compare the 500 TR W/C performance on equal terms with racing machines 30yrs younger.
Completing the three laps confirmed that the suspension setting was spot on, engine was now revving to 11,000rpm so we needed to gear up, but best of all; the top Irish road racers came over to see what kind of bike had passed them down the fastest part of the course — both were riding Hondas, 750cc RC30 & last years RS 250cc ps... It made an old man (me) very happy!
More in the pipeline for later in the year...
Dave Maskell, August 28, 2006
August 28, 2006
The photos courtesy of Dave Maskell.
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