General 500F Engine

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General 500F Engine


Shed Troglodyte
Aug 3, 2009
Sunshine Coast, Australia
So, having been blasting around the neighbourhood in my rebuilt, but as yet unregistered, 695 replica, I decided to strip the original 500cc engine which was sitting at the back of the garage looking neglected.

This engine had about 173000 km on it, with as far as I know, no major work. Prior to stripping, it was a bit hard to start, a problem I put down to faulty points/condenser and an old coil and when it did start it was a bit rattly. Apart from being quite carboned up, it is generally good shape and I've send various bits off to be cleaned and measured so I know what I'm up against if I decide to rebuild it.

So far, the major items of wear were a very loose timing chain which had scoured a groove into the inside of the cover and one burnt/split exhaust valve. The bores and rings look OK, though ultimately should be replaced. Superficially, the rest of the crankcase and head looks fine, though I'll find out for sure next week.

If I do rebuild the engine, I thought that I might fit slightly larger intake valves (? 34mm rather than 32mm - there is enough room), a sportier camshaft and a 126 carby. I'll leave the capacity alone at 500cc. When I get the final inspection reports (crank, head etc.), I'll see how fat the piggybank is ......

On a side note, the 695 that I built is a huge amount of fun - the twin pipe exhaust gives it a real rorty sound and even though it's not quite run in, it has a lot more poke than the standard 500, though as you see below, my original engine may have been down a bit on power. I've still got a little bit more to do before I get it registered and then I'm not quite sure what I'll do with it.



  • Timing chain cover.jpg
    Timing chain cover.jpg
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  • Burned exhaust valve.jpg
    Burned exhaust valve.jpg
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