Owen, I have a Yamaha FJR 1300 that produces 148 hp and I don't have the engine weight but I doubt its much over 100 lbs. But, to produce 148 hp its revving over 8800 rpm. Its a V4. Which I would trust more then a V twin as the V4 is far smoother. Vibration
It would take a pretty serious reduction unit to get those revs down to prop speed. But, I have little doubt with all the years I have big yamaha engines, it will turn those rpms for long periods if time. My concern would be heat, listening to an engine scream that high for long periods of time because I feel my bike needs a taller gear at only 70 mph and 4000 rpm. Then there's prop loads on the bearings and crankshaft. I guess a beefy reduction unit may handle that but I'm still thinking about how small the crankshaft is in dimensions , length and diameter. There are others here far more qualified to answer this. Jeff York KR2 Georgetown Scott County Airport, Kentucky On Sat, Jan 26, 2019, 10:17 PM svd via KRnet <krnet@list.krnet.org wrote: > > Has anyone installed a yamaha on a KR? > > I’ve been flying with a STOL crowd and a number of them have ditched 912’s > in favor of the yamaha. > > Numbers sound good - 140hp at 175lbs, at a fraction of the Rotax cost. > > But size and shape are quite different, and I worry about an engine that > rev’s to 10K. > > Owen > > > > _______________________________________________ > Search the KRnet Archives at > https://www.mail-archive.com/krnet@list.krnet.org/. > Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. > see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change > options. > To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org > _______________________________________________ Search the KRnet Archives at https://www.mail-archive.com/krnet@list.krnet.org/. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options. To UNsubscribe from KRnet, send a message to krnet-le...@list.krnet.org
