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Believe it or not this machine started life as a Triumph 3TA back in
the late Seventies! - Let me explain...
My father always did his own vehicle maintenance and as a kid I was
in awe of his ability to dismantle anything that was broken, fix it,
reassemble it and get it running again. I suppose it was this that conceived
the Petrol Head in me.
In a mad phase he decided that he wanted to revisit his youth so he
found a virtually scrap Triumph 3TA and we both set about restoring
it (not to concourse - I hate those bathtubs) but back to running order
looking more like a 60's Bonneville. It took us ages and I learnt all
about mechanical and cycle part restoration but it was eventually finished
and ready for the road - however he was dead set against me riding a
motorcycle in my teens (and he was right, I am sure I would have killed
myself).
Unfortunately 3 months after it was finished someone decided they also
liked it and nicked it - with the insurance money we bought a 1959 Dominator
99 in a very poor state - my first introduction to the Norton marque.
My Dad joined the NOC to get support but family circumstances then changed
and the bike lay unused, unloved and unrestored for the next 20 years.
I always had my eye on it and in the late 90s I suggested that he needed
some space and he should give it to me for restoration. I clearly remember
my wife’s reaction when I brought it home with two crates of other
assorted 'spares' - she didn't believe it would ever see the light of
day.
Three years later it was finished with huge amounts of assistance from
new friends at the Thames Valley branch of the Norton Owners club near
London, It was fitted out in cafe racer style with a gorgeous 5 gall
Manx Alloy tank, TLS front brake, belt drive, SS Cam & downdraught
Head and swept back pipes - all in standard black and silver.
However this is where I started a Norton trend that is still happening
to this day in that I ‘rebuild but never manage to use’ as
I can't get past the running in period before something breaks. The
first thing that happened was it dropped a valve head at 90kph on the
way to a club night. Not wishing to be fleeced by a recovery truck I
rode the machine on one cylinder to the club night and a friend helped
me get it back in his van. Later inspection showed that the valve head
had snapped off the stem, rattled around in the combustion chamber,
gone through the piston, been trapped between the crank and case, cracked
the case and ended up in the bottom of the sump - and it had still gone
on another 10 miles in this state!!!
The head was FUBAR but contacts in the club located another SS head,
the engine was welded up and repaired and the whole thing completed
just before UK Norton day in 1999. I joined up with other club members
and I ran the machine in on a hot summer day (hot by UK standards -
27 degrees!!). On the way it temporarily died and came back to life
- funny I thought - but kept going. At the rally I discovered that the
oil had been completely consumed in the heat of the new engine and the
pistons had nipped up (sounds familiar) but again I had ridden it a
further 25 miles in the heat with no oil without it seizing or sustaining
any serious damage - these engines are tough. At the rally it was refilled
with oil and never missed a beat.
The top end was stripped on return and the piston/bore cleaned temporarily
cleaned up and put back together, apart from an increase in oil consumption
(pint every 200 miles) it was fine - leave it until the winter I thought.
However on the way to the next club night some idiot pulled out in front
of me at a low speed junction and wrote the front end off.
So what about the Norvil – well this is where it starts to put
in an appearance. One member of the club lived local to me and we regularly
went out riding together around the Berkshire countryside – he
had a black 850 Norvil with a racing history and it went like stink
and looked great.
For those who don’t know about Norvils they were built by Norton
Villiers to compete in the early 70’s version of what is now WSB
racing and Peter Williams had plenty of success before the shortsighted
management team pulled the plug. These factory produced machines are
very rare (and how to identify them is a trade secret!). The factory
continued to produce kits for Joe Public to convert his Combat Commando
into a Production racer and mine is one of these.
The basic kit came with all the cycle parts, head steady, cam and pistons
and that was about it – the rest was stock Commando – back
to the story…….
The insurance pay out was made and sat in the bank whilst I plucked
up the courage to start again. I was then browsing the For Sale section
on the NOC site and came across a Yellow Norvil 750 Commando for sale
for a very reasonable sum - the money in the bank was too much temptation
and so I traveled to the remotest part of Norfolk (the big bit sticking
out into the North Sea just north of London) and struck a deal.
I mentioned earlier that I wasn’t having much luck with my rebuilt
machines – one of the problems is purely to do with me! I can’t
stand seeing one of my machines leaking oil or smoking (why the hell
is he riding old British machinery then I hear you say – damn good
question!) as I think this reflects badly on my mechanical competence
so I am always fiddling. For anyone who has bought a classic machine
they will know that it takes months, maybe years, to remove the gorilla
antics and ignorance of previous owners (grease in the swinging arm,
stripped threads, incorrect parts etc.) and this was no different.
After getting rid of the basic mistakes I considered it good enough
to thrash round a couple of track days and to take me to the 2001 International
Rally in the South of France (See the cover of RoadHolder 220) and it
behaved really well but was chewing oil at a rate so (being what I am)
I decided to strip the engine and fix it.
With luck I lived very close to someone with a worldwide reputation
for building Wasp racing outfits and he helped me rebuild the engine
(bar the rebore, I did that – more later). The first work he did
was to fix the inherent weakness in Combat engines – the oil pick
up. In their inherent wisdom Norton decided to produce a hot version
of the Commando engine and then compromise the integrity of the lubrication
system at the same time - with dire results. I have vague memories of
what they did wrong but it involved moving the scavenge pick up but
forgetting that the crank threw the oil to the back of the crankcases!
He converted the oil pickup back to standard (through a combination
of welding, milling and drilling) and rebuilt the bottom end with new
superblends and a PW3 cam as the original 2S was showing signs of wear.
Luckily I turned the engine over with an unbolted barrel and watched
the barrel jump up and down as the cam fouled the cam follower tunnels
– this was fixed using a normal half round file!
The original HC pistons were worn and were replaced with oversize JP
High Compression units, these had to be recut for the big valves - it
has been through Mick Hemming’s shop at some point as it has one
of his early 41mm big valve head conversions. The inlet valve guides
are custom made as the valve is re-angled when converted – these
were worn so were replaced as well as the stock exhaust guides.
The rockers had already been lightened and polished at some point and
the head fitted with WS racing springs so its good for about 7500 rpm
(if I ever finish running the bloody thing in!). As the inlets have
been re-angled the rocker approach angle is wrong so Ducati lash caps
have been fitted to the valve stems to give a larger contact area –
this required the push rods to be shortened (writing this down I suddenly
realise why I never seem to spend an evening away from the garage!).
That’s it for the engine I think – apart from the stock Norvil
cycle parts it also has electronic ignition, vernier Isolastic adjusters,
a belt drive and a front fork brace. The latter comes highly recommended
– it totally transformed the handling. The gearbox had a few bushes
and worn gears replaced but it was in quite good nick considering its
age.
By the time this was all done I emigrated to Australia after having
run the new engine for about 30 minutes in total and dreamed of running
it in on the coastal roads of NSW!! After getting it here it had to
stay in storage for nearly 12 months whilst I got the family settled
in, schooling and job sorted and eventually a permanent place to live
(Mandatory garage of course). The bike was delivered in remarkably good
condition with some light metal and alloy corrosion and the corner of
the Perspex screen broken – nothing that couldn’t be fixed.
Some preliminary mechanical checks and priming were all it took to get
it started safely and after getting lots of club help to get a Historical
Plate I was able to start the running in period. After about 200km I
decided it was ready to take on its first club run to Huskisson –
this brings me back to never being able to get the thing run in!!
About 50km out of Sydney at between 3000 and 3500 rpm the bike died
on me twice in a five minute period – odd I thought, fuel tap on?
Yep, Ignition OK? Yep – what the hell is wrong now? As the run
went on the bike started a noise that initially sounded like a loose
tappet (half the club inspecting it at the destination couldn’t
find the problem) and by the time I was back in Sydney it sounded like
a major problem. At this point I did what I always do – stick it
in the garage and forget about it. However curiosity got the better
of me and a top end strip showed that the pistons had nipped up one
after the other (told you it sounded familiar at the start of this story),
had gone out of shape and were slapping around in the bore. However
the noise was that bad that I was sure the bottom end had gone so with
Pete Combat’s help that was stripped and but subsequently proven
OK.
I also found that the carbs were gummed up with resin as the Australian
fuel was slowly dissolving the inside of my glassfibre tank! This has
now been fixed (thanks Brett) and the carbs cleaned up (I think, see
the postscript at the end)
Tracking down what had happened with the pistons took some time talking
it through with JP but it ended up being inexperience on my part. JP
machine their pistons to fit to an exact oversize bore. I had asked
the borer to machine to the piston skirt diameter plus 5 thou –
wrong!! The bore was actually two thou undersize for the pistons and
that was enough for a partial seizure on a new engine.
I replaced all the damaged parts and reassembled it in time for Norton
Day along with a new swinging arm spindle and bushes and a second gearbox
adjuster to ensure the belt aligned properly. All the blood, sweat,
tears and money were put aside as I started clocking up the running
in miles. However it was definitely very smoky and I was really going
to just give up but Pete Combat and I had an agreement that whoever
didn’t make Norton Day would get there arse kicked by the one that
did!
Telephone calls were exchanged over the days running up to Norton Day.
He was battling with getting all sorts of nonstandard parts to fit back
into a working machine and I was battling to get a fairly standard machine
just bloody working. I almost threw in the towel, as I was sure that
I had broken a ring or slipped a seal off one of the inlet valves and
did not have the heart or time to take the head off again.
In the end I just rode the damn thing and told myself that the rings
may just be struggling to bed in to a fairly aggressively honed bore
and ‘she’ll be right mate’. We had a great day and I
even managed to pick up ‘Best Special’!! But…. On the
way back it was definitely laying blue smoke from the right hand pot
and I just couldn’t hold the urge to strip it again and make sure
that there wasn’t a problem with the rings or the guides. So yes
– I stripped it AGAIN and guess what – nothing was wrong.
So now it is back together and ready for the run to Kangaroo Valley
but I better go at the back!!!
So – there it is, a long story about a Yellow Norvil 750 Production
Racer that owes me big time, so if there is a God up there can I please
just have 1500 miles of uninterrupted mechanical running in so I can
stretch it legs – please!!!
Jonothan |
