Rider
Reports on Suzuki TC305
Suzuki
TC305 by Joe W Richardson (Sep 2005)
The advert pronounced
Suzuki 305 Streetfighter £450 and the year was 1993 with the importing
of motorcycles and spares by the container load from America in full
swing. The bike was just one of a dozen others being
advertised as ‘recently in’ by a breaker/importer in the NE of
England. But what was a 305 Streetfighter? A phone
call confirmed it was a Suzuki two stroke twin, it had ‘305’ on the
side panel and it looked Hustler like, ish, well sort of. So
off I went for a look and sure enough it was a 305 with raised
exhausts, bump plate folding footrest etc. I had heard of
305’s but had not seen a picture of one with raised exhaust
before. It was missing the LH silencer and the LH carb (huh,
why???) but other than that it was complete so I bought it.
Once home, the bike
was checked over and apart from one rusty fork bottom the chassis
seemed in good condition. Paintwork was reasonable with only
minor rusting evident on seams etc. One or two small items
were missing as well as the above already noted parts but as these were
general Suzuki bits it should not be a problem.
Unfortunately, the engine was another story with both bores and pistons
badly corroded plus the crank had filled up with 30 years worth of
desert sand. Remarkably the rest of the engine was in as-new
condition plus the 305 crank was a standard ‘twin’ type used in a
multitude of the later 250/350 bikes and thus readily available as a
spare. The only specific 305 parts needed for a rebuild would
be replacement pistons for a rebore, LH carb plus the
silencer. All in all, with ‘stuff’ coming over from the US in
increasing quantities it I thought that it should be no problem to get
the parts needed.
You know, ‘should’ is
an extremely good word. It implies a blind optimism of
certainty and is a word that with 20-20 hindsight should not be used in
a sentence. Doh!!!! After deeper research it turned
out that the bike was rare even by rare standards being manufactured
for just one year and exported only to the US.
For the next six
months I searched everywhere I knew for the bits. No new
parts were available and the only second hand parts were on another TC
that had been imported by DK near Stafford. This one however
was not for breaking at that time. So that was that, I could
have used T350 silencers to get the bike on the road but without
pistons and a carb the rest would not happen. Admitting
defeat, the bike was put into deep preservation i.e. piled into a
number of boxes and then assigned to the bottom of the overhaul list.
Move forward eight
years and a chance visit to DK’s after the early Stafford show in 2002
found that their TC305 had still not been sold. By now it was
in a bit of a state with broken instruments, missing tank, seat, side
panel and air box but, it had a good LH silencer and its
carbs. The price tag was still £600 and a number of other
restorers had looked at it and backed off at that price.
After all who had the parts to complete it? Not I, but
combining the two bikes would bring completion of one that much
nearer. Additionally, if I didn’t buy it then both bikes
would probably be destined to remain as ‘failed’ restorations, so with
some other bits thrown in I bought it.
The original bike was
taken out of storage and the years had not been good to the
paintwork. It had started to peel off in many areas and a
full respray was now required thus delaying the rebuild until early
2003. On the plus side, the chromework polished up very well
and all alloy parts were mirror polished with the heads and barrels
blasted. The engine in the second bike was in a worse state
than the original bike with bores very poor and the LH barrel missing
top fins. New pistons still had not been found so the bores
of the original bikes barrels were honed as they were not too badly
worn. The pistons were bead blasted clean with rings in an OK
condition and so with a reconditioned crank the engine was
rebuilt. Unfortunately the carbs on the second bike were
badly corroded and a pair of later model T350 carbs were
used. The main and needle jets on later carbs are totally
different but I figured they would be OK for low throttle running even
if they didn’t work properly for large throttle openings. The
rebuild was completed with the usual new tyres, chain and sprockets,
etc. 
Finally in late May
2003, 10 years after the original purchase, the bike was fired
up. The engine ran smoothly though the top end was somewhat
noisy even for a two stroke (marble’s being shook up in a baked bean
tin comes to mind). Hot compression was taken at 130 Psi
which wasn’t too low so after test running to settle everything down
the bike was taken for an MOT and then Registered. The bike
lacked any real pull in sixth gear so the 15 tooth gearbox sprocket was
changed for a 14. This improved matters but it was obvious a
‘rebore’ was required.
At this time E-bay was
beginning to make itself felt in the search for restoration parts and
as luck would have it a complete TC305 was found in the US.
The bike was in good condition and being broken for spares simply
because nobody wanted to buy it. This was the answer to the
question of what to do with the second bike from DK’s. Though
I could not afford the shipping for a whole bike, I bought it anyway
and had everything bar the wheels, frame and engine bottom end shipped
over to England. The result would be enough parts to make a
second TC305.
I also had another US
contact that sent me a pair of T305 pistons at plus 0.5mm so I could
rebore the original bikes barrels. However, on removing the
barrels the new pistons dropped straight through the bores.
What’s this, the original pistons did not have oversize markings on so
they should (that word again) be standard? Yup they were
standard; that is standard T350 pistons.
I will
digress. The T305 was an interim model between the previous
T20 (super six) and the later T250/350 models. The engine was
designed as a 250 and the 305 was a bored out version but, the bored
out version was released first. Sounds strange and a bit back
to front? Not really. Suzuki already had a good 250 in
production so its replacement could wait until development was
concluded plus they had just released the T500 twin. What was
needed was something in the middle a sort of ‘super’ 250 hence the
305. This was rushed into production and though OK it was to
show a lack of engine ‘development’
However, a 305 doesn’t
really come over as being much bigger than a 250 and 350 would sound
better. Unfortunately the barrels of the 305 could only be
over bored to +1.5mm before loosing structural integrity (as they say
in Star Trek). To fit bigger barrels (or increase the crank
throw) to give 350cc would mean a re-design. The result was
to make the bore +1.0mm above the 305 giving 315cc which left one
rebore size still possible. The ‘missing’ cc’s would be
‘miraculously’ added by the marketing department by putting a ‘350’
badge on the side panels.
To continue
then. The barrels already at plus 1.0mm were bored out to
take T350 pistons at plus 0.5mm. The porting of a 350 is
somewhat different to the 305 necessitating the piston cut-outs and
skirts profiled to suit the 305 barrels. Once rebuilt the
difference was immediately apparent with the engine pulling well even
at running in speed. Unfortunately it was now obvious that
the 350 carbs were not suited as the engine was running very
hot. The originally fitted ‘standard’ 350 pistons had not
been profiled and made the barrel porting act more like a 350 thus the
carbs matched. With the re-profiling of T350 pistons at plus
0.5mm the porting was then correct for a 305 and consequently 350
jetting would result in weak running.
A few weeks later the
parts from the stripped down TC arrived from the US. The
carbs appeared in much better condition so were cleaned and fitted to
the bike. Running performance was much better but the engine
still seemed to run hot however, this could have been due to the large
raised exhaust pipes running close to the barrels and thus reducing the
cooling effect. Though smooth at 4000 Rpm, the engine ran
very rough below 3000 rpm and tend to four-stroke badly showing it was
running rich at small throttle openings.
Over the next few
weeks the carbs were to give a lot of trouble with intermittent running
and poor idling, this was eventually found to be caused by bits of grit
in the idle drillings. I must have stripped and cleaned them
about six times including blowing through with air but every time
another small bit would block the idle jet after only a short time with
the engine running. The final solution was an overnight soak
in chemical cleaner thus removed the last of the corrosion in the
drillings.
It was though all to
come good and on the bikes first long run out it was awarded first
prize in the VJMC show at the Whitby Regatta. At this show
you just turn up and all the bikes are parked in a row next to the sea
front road. The public (and other riders) are then asked to
vote for the best bike in the show. The TC is quite stunning
with the large high rise pipes either side a very prominent
feature. It received the general public vote and many other
bikers thought it was a stinger so it got lots of the ‘biker’ votes as
well. OK, to those who know it looks nothing like a stinger
(I have a handful of them as well) but I didn’t mention that until
after the prize was given.
The bike draws
attention when parked due to the unusual look and the fact that it is
quite large and very ‘shiny’ compared to the modern ‘plastic’ off road
types. Youngsters seem especially enamoured and they are
quite surprised (and disappointed) to find it is not a new model but in
fact over 35 years old and therefore not available from any bike dealer.
Just to be sure with
regards to the rich running, the better set of standard barrels were
rebored with plus 0.5mm pistons and fitted in lieu of the well
overbored pair. As of Sep 05 running in is just about
completed however the engine performance is still the same and so the
carb needles were lowered slightly to weaken the mid range and this has
helped somewhat to negate the rough running at low revs.
To summarise, the bike
goes well on the open road and handles pretty good for the era but the
lack of engine development prior to release is obvious.
Despite trying a number of fixes, the engine still badly four strokes
at ‘town’ speeds and is a real pain. The gear ratios are also
poorly thought out with an especially large jump to top gear.
Looking on the positive side, this ‘false start’ did allow the
250/350’s that followed to have all the little foibles of the 305
engine ironed out before they went into production. The
result for the later bikes was porting that gave very good running
throughout the rev range with well though out gear spacing.
The TC305 is a very
rare bike as I know of only two others in the UK that may be fully
roadworthy with perhaps a few more kicking around in the restoration
stage (one of them is in my shed)!!
Finally, the TC’s road
brother the T305 is probably even rarer in the UK and funny old thing,
I also have two of them; but that’s another story.
Top
of Page
