South Devon Classics engine rebuild service caters for all types of motorcycle engine, from a single cylinder two stroke to multi cylinder four stroke superbike engines. We can undertake all types of engine work from a two stroke top end rebuild to a superbike cylinder head reshim or complete strip & rebuild.


Single or multi cylinder engines, rebores, crank rebuilds & crank bearing & seal replacement. When undertaking a restoration on an older two stroke engine, it is always advisable to renew the crankseals as these do go hard & will draw air & be very difficult to start. We always try to use new genuine seals & NOS parts wherever possible.


Single or multi cylinder engines, cylinder head reworks, valve clearance checking & re-shimming. We carry out compression testing & cylinder leakage testing prior to any work commencing on any four stroke engine as this gives an indication of the general condition of the engine. Older engines or engines that have been stood for some time will generally require valve stem oil seals replacing as the seals do deteriorate & go hard over time.


Honda XR500 engine imported from America, lacking power & smoking under acceleration. Engine was stripped, piston had seized at some time & the valve stem seals had gone hard. Cylinder rebored to 1mm oversize & a Wiseco 11:1 high compression piston kit fitted. The head was stripped, valves decarbonised & new stem seals fitted. 

Suzuki GSXR 750 "Slabby"engine rebuild. Engine arrived in pieces in various boxes, casings had been vapour blasted & painted. Cylinder head has been stripped, thoroughly washed to remove any vapour blast medium, valves decoated & lapped in, rockers/rocker shafts cleaned & new valve stem oil seals have been fitted. Crank has been measured with Plastigauge to determine the bearings required & a set of Wiseco pistons have been fitted.

Honda TL250 engine circa. 1973, imported from America that is going into a period trials bike. Engine had a snapped timing chain & the cylinder head was full of "Idaho" dirt. Miraculously no valves were bent but they were stuck in the guides. Engine has been completely stripped, head refurbished, new piston rings, seals, gaskets & engine covers repainted.

The completed engine ready for collection.

Honda XR200R engine that is having a "big valve" cylinder head conversion. Inlet valve size is up to 32mm so valve to piston clearance needs to be checked & piston valve pockets may need deepening.

Yamaha IT250 & 465 engines. Here at South Devon Classics we have gained a reputation for rebuilding these "Beasts" of two stroke engines. We have rebuilt at least five 465's & several 250's including a 250 for our paintwork specialist, Lee Thompson. Here are some images of some of these iconic engines.

In the shadow of its bigger brothers, the Yamaha IT 175 & 200 bikes were favoured by 1980,s enduro riders. Again we have gained a reputation for rebuilding these brilliant little lightweight engines.

We had a very sorry looking Suzuki GT750 "Kettle" engine in for rebuild. Had been left with the head & barrel off in a barn. A complete strip with new pistons, rings, oil injection pipes, crank seals & a self generating race ignition fitted.

Yamaha RD350 YPVS "Powervalve" engine in for a full strip, inspection & rebuilt with new crank seals. Had been standing for some time but on inspection, it revealed that it had a rebuilt crank, new rods & had been rebored.

Yamaha FS1-E or "Fizzy" engine rebuild. Had noisey crank bearings & clutch problems. Stripped, rebuilt crank, new piston & rings.

Moto Morini 350 V Twin engine. Owner had drained the oil during a routine service to find large pieces of metal & swarf in the oil..

Engine was brought to us for stripping to see where the metal had originated from. On dismantling the engine, it was found that the left hand crankshaft bearing had disintegrated. No idea where the missing ball bearings have gone!