Peter Bosman, of the Netherlands, has fitted an Aprilia 650 single lump in place of the standard 668 twin motor.  The bike is available for sale at present, for 17,000 Dutch guilders, or maybe that's Belgian Florins?  My dutch isn't really up to the task.

This is some of what Peter has to say about his bike:-

"It is far too much work just to improve on the standard engine. It's more effective to upgrade that one. Quite a bit cheaper too!  I replaced it because I was at the end of the development of that engine.  Mine kept pulling the case studs. So for me the logical next step was to replace the weakest link with a realy good engine. The Rotax-Aprilia engine has a lot of potential. It may, because of it's five-valve head, be far more of a challenge than the BMW sister-engine, but I just love this Apfelbeck design head and tuned it to bring out this concepts strongpoints.

"The improvent is just the injection!  It's an altogether different animal now: at Assen I could easily beat the Laverda best times with a clutch slipping at 6K revs.....

"I have lots of detailed info. However all in Dutch and I do not have the time to put it in English.  Drawings etc., it's all there. Lots of details about the electronic injection and it's set-up too.

"Bert, our club treasurer has tested my bike and was flabbergasted; it's like an RS250 twin with grunt from 3 to 7.5K rpm. It has about 60 horses on the rear wheel at 7K and pulls the same top speed as a lightly  tuned 668 at a tanked up curb weight of 145 kg's.  Thus it is well over 60 kilo's lighter than the 668 with an even lower centre of gravity and steers like ... well, like a 60 kg lighter 668 with a lower centre of gravity, lots more grunt and lots lighter wheels!  The bad and good news is that it is for sale. Why? Because my wife was killed whist racing in the '99 TT on the isle of Man so I am a bit fed up with it.

"No, it's not cheap. It's well sorted. In fact so good that Jan Witteveen called to make his compliments. All good quality work and material and it comes with a full set of Marchesini's wheels with discs and both mechanical and electronic spare parts. Also a (Laverda SP cup racer) carbon/kevlar racing fairing."


© Steve Carr, 2001-2007

Site created February, 2000.  Last modified Friday, May 15, 2009

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Last updated
30 May 2005