Rotax engine - Spondon frame

Here is the story.

I read a Cycle Week article. Tony Murphy, who deals with Rotax engines, in California had installed a Rotax 250 single cylinder engine (type 257) in Yamaha TZ250 frame. Of course, you lose some power but the bike is much easier to ride. I understand that they were racing the bike in US Sound of Singles classes that allowed two-strokes as well.

After awhile I purchased a rolling Spondon chassis. The owner had gone from solo racing to sidecars and used the Yamaha 250 engine parts (mainly cylinders) for his 4 cylinder 500 cc sidecar engine.

After this a Rotax 250 single engine was purchased. The cheapo plan was that my friend would use the engine in the winter in a KTM chassis for road racing on ice (see iceroadracing.com to get the idea) and I would use the engine in the summer. Well, it was already August when receiving the engine from previous winter use. And, I think, they found better setups for ice, anyway.

The engine is very nice. Six speed tranny, counter balance shaft for smoothness, and very ingenious pneumatic power valve. Tony Murphy says that most people liked his bike and were actually scared by the speed. Two of his old pals that tested the bike complained it was too slow. These two gentlemen were the late Don Vesco and Yvon DuHamel.

More on Rotax 257

Here is link to an Aprilia 125 with the same type Rotax engine. The text is in French, but you can
use BabelFish if you do not understand French http://aprilia125rs.ifrance.com/aprilia125rs/page23.html
Alfer Enduro and Supermoto come with this Rotax 257 engine. It is also very popular in karting
Rotax engine was used in Scorpa trial bike. They still use this engine in their Easy model, but for their other models they now use Yamaha engine. They also have a 4-stroke model using Yamaha engine. The rumour has it that the bikes will be sold as Yamaha TY models in Japan
Another enduro bike to use this engine is Kram-It 250.

Thanks to Tony Murphy. Contact him for purchasing Rotax engine.

Some Rotax 257 applications

Rebel Star 250	Rotax 257
Rotax engine without the power valve
Alfer 250 Enduro	Scorpa Easy
Scorpa girl- easy on the eyes

Spondon Rotax

The 80's style seat was too ugly	Later seat is better looking and will be used
Fairing
Cleaning and polishing the frame	Öhlins shock
	Front fender needed please inform
	The rear set design.
With the old engine mounts & the 17" rear wheel	The front wheel hit the radiator when braking. So we had to make room for the power valve. The setup was not that good looking.
The new radiator is from some 1000 cc street bike.	Instrument panel with Scitsu tacho (recommended) and temp meter See the vent holes.
The new radiator	The new front engine mount
Rotax 257 We did first the engine mounts of steel as it was easier. The new mounts were later made of aluminium.	Water tubing
	The new rear mount
New pipe & engine mount	See how the engine mount is made
Another view of the rear mount	Engine mount - under construction OK, the pictures are not in chronological order
The pipe is custom made. The silencer is a Yamaha YZ250 unit	Bare seat
Seat base	Seat foam
The final one	The tools needed
Alex the Tailor. Those old enough will certainly remember the first Jack Bruce solo album: Songs For A Tailor.	The sceen. When enlarging the image you wil notice where the drill slipped
Old engine mounts	New (Alex designed) engine mounts
A road racer that needs no pushing	The kick starter is there also for street use. Is the bike really street legal in Finland? Certainly not.