64 PERFORMANCEBIKES.CO.UK|MARCH
With the frame back on his bench (for now) and the
RD500motorinstalled,Jerry’snexttaskwastoadda
swingarm. Although a TZR250 3XV unit would have
slipped in, visually it wasn’t quite correct and it also ran a
150-section rear tyre instead of the 180-section of the GP
bike, so instead he decided to modify a 2006 YZF-R6
swingarm to fit into the chassis.
“Getting the R6’s swingarm to fit was a total bitch,”
remembers Jerry. “The TZR’s frame is far narrower than
the R6’s, so I had to remove a load of metal on the pivot
point and that meant there was now no room for the
bearings. In the end I sourced some extremely narrow
bearings and it just about slipped in – which is when I
discovered the frame had deformed while the guy was
welding it up and the swingarm’s axle didn’t fit as the
frame wasn’t inline.” Back the frame went...
With the frame’s issues rectified, Jerry sourced a set of
2000 Yamaha YZF-R1 wheels, which have the correct
three-spoke design, but the rear required its hub to be
machined to get the drive chain sprockets inline, as well
as new spacers. He also repositioned the rear brake
caliper’s mounting point from the top to the bottom of the
swingarm as that’s where the GP bike’s caliper is located.
This may sound easy, but it involved modifying an R1
brake carrier, chopping the R6’s locating lug off and then
welding it all back together. And all just so it looked right.
The next challenge was working out where the
suspension linkages and shock mount should go,
something Jerry solved by gaining access to R6 technical
drawings from a source in Japan and replicating them in
really should have known about.”
With a rolling chassis now completed, Jerry embarked
on the fiddly little bits that take the time and dedication.
He fabricated items such as the powervalve mount, entire
instrument cluster and all the various brackets and
mounts himself in his shed, using a hacksaw and files as
he didn’t have a lathe. He repositioned the powervalve
motortothefront of thebikeasthat’swhereitisonthe
built his own subframe out of steel to the
ons of the YZR aluminium unit – just with
ssothatitcanhousethebatteryrequiredto
dbike’s electricalsystem.Theswitchgearis
ecial andhaseverythingontheleft-hand
ding thekillswitchwherethepassflasheris
ocated andanLEDlighttoindicatemain
on. It was a lucky eBay find and Jerry has
what it actuallycomesfrom–hopefullya
a product of some description!
inal touches that included Jerry building a
k-up of theradiatoroutofcardboardbefore
pecialist engineering firm Performance
Fabrications replicated it in metal, plus a
beautiful exhaust system also built by
he bike was ready to be dressed.
ckily, Harris Performance could still make
YZR500 fairings from ori moulds, but
ssue with the RD500 eng ts carbs’
ition. TheYZR500hasits insidethe
V in a bank of four where the RD500 as
m on either side of the motor in banks of
o, whichmakesthemotorabout10cm
der,” explains Jerry. “In the end I had to
iden thebellypantosplayoutthefairing’s
des so thecarbsfitwithinit.Ialsomodified
he air scoops, which is a bit of a moot point.Fairings
Harris still make period
YZR500bodywork,sothat
waseasyenough.However,
the bellypan had to be
widened to account for theMDF,whichhethentooktoanengineeringfirmtoturn RD500’s carb positioning.
into aluminium. Compared to this, slipping the 2000
YZF-R1’s headstock and forks into the TZR
breeze – aside from having to get the bear
downtothecorrectsizebyaspecialistfirm
And yes, technically the YZR ran an Öhlin
forks, but Jerry’s budget was already rathe
certaincompromiseswereforceduponhi
springmayappearinthefuture,aswellas
mudguard as the R6 unit the bike currentl
shorter and not ribbed like the YZR500 pi
Witharollingchassisnowinhisgarage
addedtheR1’sbrakesandmastercylinder
but after dabbing the brakes and checking
thesuspension’smovementhediscovered
arathermajorissue.
“On three-quarter fork movement the fr
wheelhittheforwardcylinder’ssparkplu
IsenttheforksofftoKaistogetthemre-va
andanextendedbumpstopaddedsothey
threequartersoftheirmovementwhatth
usuallydoinafullstroke,”heexplains.“B
eventhen,thefirsttimeIrodethebikethe
tyreknockedthesparkplugcapsoffandb
thetopoftheplugsduetoalackofclearan
IhadawordwithamateatNGKwhofoun
some super-trick plugs that are incredibly
short,butcost£45ago!Again,thislackof
clearance is something the chassis builder
SPECIAL / YAMAHA SONAUTO YZR500
‘I ALTERED THE FAIRING TO HELP IT
FEEDRD500CARBS,SOIT’SNOT
AESTHETICALLY100%CORRECT,
NOT THAT YOU WOULD KNOW...’
Rearsets
Jerry fabricated a YZR-style banana-shaped bracket for the
hangers, which costs £14.95 for the pair from the Far East.
He says modern-day rearsets would look too posh; the race
bikes were rough and ready. Original ‘TZ Racing’ footpegs
would have cost £180 per pair! That tube is actually an HRC
kit part, and the Nissin master cylinder is from an RGV250...Jerry would sell it for the
right price. Get behind
us in the queue...