Two Vincent sightings in the last week

If we are on tales of this kind I once rode an MZ250 from Birmingham to
Leeds with a holed piston. Somewhere around Coventry it started
misbehaving and would only run with the throttle wide open - so I just
held it against the stop all the way. My mate (who owned the bike came
up the next weekend and we stripped it down to find a hole in the
piston. He just replaced it and it was fine. The MZ250 might have
been a bit agricultural, but it was a solidly built thing (with totally
c__p brakes!)

--

 

Don't get me wrong: I'd love to own one (and a DBD34 Gold Star), or at
least ride one for a couple of hours, but they are, when all is said
and done, a machine whose time has been and gone as a superbike.

 

Well, not so old in this case.

Still, 165BHP at 6500 RPM and 130 ft lb at 5800 RPM from a V-twin. Hur
Hur Hurr!

Pity it's only a marketing device. Also, unlikely to even get through
SVA over here.

 

Eh? How does a single cylinder two stroke run with a hole in the
piston?

Can't see that working 'cos you'd get no compression of the charge to
ignite it
and no way of pushing the charge up the transfer ports from the
crankcases
on the exhaust stroke of the piston.

Of course, I'm visualising a hole in the piston crown which might be
where
I'm going wrong.

 

Sorry about the delay - bin doing other things...

If I had a DBD34 you could have it.

Now, a DBD32 - that's a different matter entirely.

 

In '63 I lost a Met-dibblery pursuit Daimler Dart on open dual carriageway.

I understand, M'Lud, tht the DD did 150 mph.

The Vin had been breathed-on and was stuffed^h^h^packed with Lightning bits.

Even by today's standards, the Vin is a lovely wossname.

 

My mate used to carry a pot-mender and a tube of Green Hermatite.

Got him home once - Ariel VB and double adult chair.

 

They don't tend to recover without some help.

Now, pushing it to the nearest bridge and heaving it over the parapet -

 

But you would be unlikely to get far with a C on three...

 

First one I almost saw - missed it by seconds - was a low-loader with FO
big wheels which had crossed the A1 somewhere up near Scotch Corner
(when it was mostly single carriageway).

Two cars - which I must have just thumbed - had gone under it.

There was a Mini rolled up into a ball the size of an armchair, and a
Vauxhall estate which a back wheel had flattened right up to the back.

There was a bump where the engine was...

I knew the ball was a Mini because of the wheels, and the back doors
with a wheel behind them bore the legend 'Vauxhall'

The driver of the low-loader was still sitting in the cab, white as a
sheet.

 

Can I join in?

I set off from Hornchurch in 1967 to go to the IOM TT. I'd borked my
femur the previous year, and kneebend was in short supply, so I fitted a
Watsonian scooter box sidecar to my T35 Douggie.

To keep the thing down on left-handers I filled the box with tools and
camping gear. Still a bit on the light side, I heaved in some spares as
well.

Halfway up Hertfordshire there was a loss of power and misfiring on the
nearside pot. I couldn't see anything wrong, so I cleaned the plug. It
ticked-over fine, but a bit of throttle, and half of it died. In the end
, thinking to clean the carb I found that the needle in the main jet had
come adrift, so the slide went up and down, but the needle noddle noo.

Approaching Norman Cross on the A1, I gave it a bit of wellie and the
crankshaft twisted on the journals.

RAC towed me into a fine motorcycle shop and scrapyard in Stamford,
where I pulled the engine apart. The owner of the place gave me the use
of his Alpha True, and I tapped the crank back into line, and arranged
for the journals on the spare to be spot-welded while I rebuilt the
engine with the straightened crank.

Tempus was fuging.

All went well until Grantham when there was this shaking. Douglases
don't shake. Then the nearside exhaust pipe flew out of the pot and
waffle-box. I tapped it back in and set off again.

Still shook, and this time I ran over the pipe and adjusted the
circularity of the waffle-box end. Using one of those deathtrap concrete
pillars which signs used to be hung on as an anvil, I corrected the
flatness enough for the pipe to be replaced. Then I started the engine
and watched.

The nearside pot was pretending to be a piston. "Bah!" I thought (or
something like that), expecting to have to look for 6 x 5/56th" BSF nuts
to resecure the cylinder to the studs. Not a bit of it - the pot had
sheared right round its circumference just above the crankcase.

A Spanish windlass round the pots and engine got me to a safe parking
place, and I hitched back to Hornchurch to pick-up a pair of pots and
pistons.

However...

They turned out to be early Plus series, which had 3/8" stud holes and
which bumped-up the c.r. by one.

Unfortunately...

Th pistons were also Plus 90 ones, and they bumped-up the c.r. still
further. We went from 7.25:1 to nearly 10:1.

I was running out of money and the TT was about finished, so I set off
back home. In Stamford again, I bought a short piece of brassed curtain
rod, which cut up nicely for spacers round the studs. Then I carried on.

Eeee, but she flew!

CLUNK!

Sodding crankshaft again! I pushed the lot the half mile to Norman
Cross, where there was an offroady bit behind an RAC box. I drained the
oil, had the engine out, and split the crankcase, I used the blowlamp to
heat the front half and change the mainshaft bush.

In a remarkably short time I was ready to put the lump back. The RAC man
remarked that he'd seen some roadside repairs, but this took the
biscuit. Then I heard another Douggie pull up in the layby. "Here's help
to get the engine back in!" I thought.

It was me mate Ralph Killips on his way home from visiting his folks, an
we rode in convoy, I to Hornchurch, then he went on^h^h^back to Romford.

I have left out a few fiddly bits, but I don't want to clog-up the server.

 

/Oily wrote:

Tristicated wankshafts/

A spot of weld either side of each end of both crankpins solves the
problem, and as long as you aren't too enthusiastic (No 10 jet on oxy,
or 140 amps for a measurable time...) the blob can be cold chiselled-off
without too much trouble innit.

Another mod is to molish an increased volume/pressure oil pump and an
oilfeed into the back of the crankshaft.

 

Next cheap Douggie you find you can hurl my way.

Mined ewe, that goes for a lot of other SOBs

Oe of my mates lightened a Mk# frame and ditto for engine. He fitted a
home-made triple capacity oil pump, a bush instead of the self-centering
ball-raace at the gearbox end, and an oil feed through the back main to
the rear big-end.

He shortened the pots a bit, fitted +90 pistons, opened-up the inlet and
exhaust tracts, polished them like unto mirrors, replaced the valves and
springs with Triumph ones, stirred in 1" Monoblocs, replaced the cams
with Stellite-coated high-lift ones of his own manufacture (yes, he was
an engineer by trade) and improved the gearbox.

This was based on a + series one, and the main mod was to turn down the
selector pegs and clothe them with (IIRC) 5/16" rollers from a Reynolds
chain, and secure them against falling off...

This made for a highly slick gearchange, which I can vouch for, as I
restored a worn gearbox myself that way.

One (500) Goldie owner was disparaging Douglas chamines, and Pat
accepted a contest. Goldie got off first, but shortly after that Pat
screame past him.

Back at he Lay-By, the Goldie rider asked: "How fast does that effin'
thing go? I was doing 105 when you went past me!"

"You must have a tuned speedo, mate:" Pat replied "this only does 90."

 

The volume and pressure wasn't, but for some reason the oil tended to
sidle by the front big-end without visiting.

Nah - seizes up: crank hits crankcase.

Getting on for that here TAAAW. There's a triangular-ish hole in the
bottom of the sump, and the (eccentric bore with vanes on the rotatybit)
pump is stuffed (and screwed) in it. IIRC it runs off one of the camshafts.

 

My old Ariel 500 twin put a conrod through the front of ther crank-case
(in 1969) about 100 miles from home. (New Zealand countryside - no bike
shops for 100 miles) Tied the flappy end of the conrod to the frame,
cut a tin can to fit over the hole, wedged it in with a chunk of
firewood
from a nearby house, pulled the sparkplug, and rode it home, topping up
the oil every 5-10 miles. I got most of the leaking oil back, soaked
into
my left trouser leg and boot. (and foot) It went quite well as a 250cc!
Was a bit worried when I hit the city, what with roundabouts and a very
well oiled back tyre.

Greg.P.
NZ

 

Oily wrote:

/Douggie/

'Handles well' doesn't describe it adequately.

On my Mk4 Sports I held-off a mate on his Dommie through the Essex lanes
- the Sports' pipes went over the pots, and I could lay it over when the
Dommie's silencers were scraping ground.

*AND* the Dommie was regularly used in classic races.

Don said he'd never sneer at Douggies again.