SmedSpeed XS650


engine rebuilds

The XS650 is a veritable icon of motorcycle design. Very popular throughout its entire lifetime, it has recently entered a rebirth stage. The initial engine design was a typical 70's Japanese engine design, very strong, good materials, and most notably all roller bearing. After many years of British designs utilizing a mixture of shell and roller bottom ends, the designers at Yamaha opted for a complete roller bearing design, amongst other cutting edge (for the time) design features, basically a 2 stroke bottom end with a four stroke top end.  These engines were built to last.

However, well over thirty five years since the last XS650 rolled off the production line, most engines are in dire need of a rebuild. Whilst they still run, and to the inexperienced seem to run quite well, most have worn to a high degree, and as a result are down on power and up on engine noise and oil consumption.

In the nine years I have been building XS650 engines, I have built engines for street bikes, sidecar Moto-cross, sidecar road race, flat track and hill climbing, in fact almost every type of racing. I have learnt a lot about these engines, what makes them go and what makes them stay together even when you abuse them badly.

I have thought long and hard and have decided after much deliberation to commence engine rebuilds for street based engines once again. The builds will be on a limited basis; if you would like me to rebuild your engine please send me a short e-mail describing your project. I have limited scope and availability in addition to my race clientele, and thus will work together with the potential client on builds that sound interesting in one form or another.

In addition to the renewed focus on engine rebuilds, I will continue to supply the sub assemblies required for owner driven rebuilds. This will include rephased, stock and lightened crank rebuilds, UK made performance cam shafts in both rephased and stock phasing, oil filter kits and carburettor and manifold kits and much much more.

I will be as usual more than happy to assist with engine build technical enquiries via e-mail or phone, and have put together detailed photographic instruction sheets for the assembly of all my products. I look forward to assisting you in the coming years......

Contact me for more details

These are experimental parts intended for racing and as such no warranty is given or implied. If you decide to buy it is on the understanding that you assume complete responsibility for any possible injury, loss or damage that may occur as a result of using these parts and that you accept these conditions of sale prior to purchase.