Comments on: OSSA 250 Monocoque

By: Lloyd Bishop

Lloyd Bishop — Wed, 27 Oct 2010 01:22:17 +0000

The street displacement was 230cc – I don’t know if this factory racer was a 250 – maybe.

Also – The HP was 50 NOT 30. My stock 250 Bultaco Metralla put out 27.5 CV.

By: Mito

Mito — Sat, 03 Jul 2010 11:20:31 +0000

I remember the Phantom MX , lovely to ride ,if slightly nervous handling , meaning it was like a race bike.
Motor was a dream.

Mito

By: Big Sven

Big Sven — Fri, 02 Jul 2010 11:12:56 +0000

There was talk of an MX rotary-valve Ossa, dropped because it was too expensive. CAN-AM Rotax did one that was great, but didn’t sell in Sweden, or Europe I think, as the Jeff Smith cycle-parts were crap and with all that power the bikes were regarded as death-wishes to ride. But I’ve seen inside a ‘Canny’ engine and was mightily impressed, and the powerband wasn’t ‘the atomic-bomb’ it was made out to be in the press, but about the same as a Maico or the ’76 HVA I raced (with the optional Ohlins ‘spanny’ mounted) but pulling from a 1,000rpm lower and with a couple of more horses on top.

I’ve just found a couple of piccies that preport to be the Ossa MX rotary development engine, and see it was very bulky, based on the existing MX engine they needed to completely redesign the gearbox area in order to pull the right-mounted carb back a la CAN-AM and slim-off the engine. Obviously money was the problem.

I did once suggest to HVA that they invite Giro to help develop the new HVA Mag-series engines (they were courting all sorts of design consultant guru’s at the time, I once met Gordon Blair, for ex) but they never did as far as I know. They did pretty-well by themselves!

There is another aspect to mull over here, politics. There was always ‘friendly’ rivalry between Bultaco and Montesa (an offshoot of Bultaco) but OSSA seemed to be outside even this cartel. OSSA’s success probably didn’t go down well in certain circles, and Giro found himself being sat-on.

Today’s thought:
Oh, to turn time back and do it all again!
(Knowing what you know now, in hindsight).

By: Mito

Mito — Fri, 25 Jun 2010 13:41:22 +0000

Sven,
the 250 Stiletto MX engine is worth a look at inside .
Cylinder is huge almost as wide on a twin.
But it has many more ports over the Enduro, Pioneer and Wildfire type cylinders.

It is a very nice engine !

I ran a 350 Super Pioneer in Australia on the road in the 1980′s with a 250 Stiletto engine and chamber , it was a nice bike.
Quite fast and we went for rides , other guys on BMW and Guzzi and i don’t remember it being left behind.

Mito

By: Big Sven

Big Sven — Thu, 24 Jun 2010 19:54:07 +0000

The aircooled engine put out 45bhp, the watercooled maybe 50bhp, but held it’s power better. Giro was a genius 2-stroke man, most underrated. He was hampered by lack of money and top-class materials, Spain had such import restrictions they were forced to only use recycled Spanish materials. Eyes boggled when they saw he was using a 44mm carburator – a HUGE carb for the day – and he sadly replied that the Spanish Amal company didn’t make the 50mm he wanted. Swoooon…. I nearly bought a 250 Stiletto MX when living in Australia, but balked when I heard spares were very hard to get. Swede Hakan Carlqvist loved the Ossa he rode in the mid-70′s, but said the same thing – and he was sponsored by the Swedish importer! He tried to buy standard spares from the factory when down in Spain but the various stringent laws didn’t allow him to do so and the factory needed the parts to make complete bikes they could export! He advised me not to buy the latest ’75 model MX’er I was interested in. The Ossa was possibly the best Spanish MX’er of it’s day, only surpassed by the Hakan Andersson Montesa, which of course had longer suspension. Strangely, we could get spares for them.

By: Mito

Mito — Wed, 21 Apr 2010 01:10:19 +0000

BTW i am sure they put out more power.
Will see if i can find a figure.
GP MX were about 30+bhp

Mito

By: Mito

Mito — Wed, 21 Apr 2010 01:05:58 +0000

This bike has everything, just so functional and different.
I am an Ossa nut and this bike just screams at you, it is the pinnacle of single cylinder engineering.
Very spunky bike .
Ive got an early Phantom GP MX bike , so light and almost delicate, you start it up and you know they did this right.
This GP in the picture must be just the nicest bike to ride?

Mito