If you don't actually need one then it's just a case of deciding what it's worth to you.
The RD engine is, I would say, more sort after, and a 4 cylinder so there is much more engine there. Maybe £400 is too much for a CR engine, I would only pay that if the engine could be seen running. If not then I would assume it's a non-runner and reduce what I would pay.
Ah now there's the problem, cr500 engine are just as sort after as the rd because some crazy folk out there in mx land like to 'hybrid' and put that monster of an engine into a decent alloy frame from the legendary CR/CRF and end up with a mind blowing lightweight crosser!(same applies to the kx5 grafted into the alloy kxf frames!) so the outcome would be 'buy it' while you can.......smell that 2smoke!
Not surprised they are well sought after for Hybrids or go karts . Me i wouldnt mind a hybrid myself but its criminal to waste such an engine in a go kart
It appears it ended early (cancelled all bids) because the seller was nervous as it had only reached £265 with one day to go. Has he never heard of last minute sniping?
It hasn't come back on sale and the seller has not replied to my email asking how much he really wants for it. I conclude that he has sold it behind ebay's back.....