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This thread is privately moderated by Geoff Potter, who may elect to delete unwanted replies.
Mar 22, 2019, 10:21 PM
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Magnum 120 FS


Hobby shop Bob my flying buddy , asked me to have a look at his 120 Magnum FS cause it wouldn't even fire let alone run . What a disaster , jammed valves , cam followers , ring , bearings were dreadful . Rust everywhere. Took ages to get apart , the gudgeon being the hardest to get out , I thought it would be the inner cam bearing as usual but came out quite well. Had to rebush both ends of the rod, make a new pin , grind the crank pin , re profile the cams grind the ends of the cam followers to clean up , reseat the valves after grinding the faces . Had to be careful with the valves when grinding them as the stems below the heads were well pitted with rust , but they seem quite strong so refitted them . The ring was stuck in the groove so soaked it in Chemcarb overnite and after a deal of fiddling I got it out with out breaking it , but made a new one anyway . Put it all together and it's a very nice engine now , runs and pulls very well , little worried about the carb as the barrel had a lot of rust type build up on it , but cleaned and polished and it does all the right things on the bench . Ugh , I've written all this and now I've lost most of the pics I took !!!!
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