cuzzy Posted February 22, 2016 Report Share Posted February 22, 2016 Greetings All I have just fitted a Mk1 concentric on my 53 Matchless in place of the old worn Mono block just wondering what jetting / slide other people were using as I cant get it to run spot on , I have to flood it to start even when hot and a flat spot on acceleration. Any input welcomed Regards Geoff Quote Link to comment Share on other sites More sharing options...
dick Posted February 22, 2016 Report Share Posted February 22, 2016 350 or 500 cc? Iron barrel road engine or ally comp engine? What size carb have you got? What month was it registered, mine is reg '53 but '54 model. Dick. Quote Link to comment Share on other sites More sharing options...
cuzzy Posted February 23, 2016 Author Report Share Posted February 23, 2016 (edited) Hi Dick Got a bit carried away should have posted more details.53 G3LC 350 alloy comp motor/wader mag (just rebuilt by David Lindsey) New amal premier carb set up as follows 26 mm bore 180 main jet 107 needle jet standard needle middle slot slide no 3 cut away pilot jet 19 Regards Geoff Edited February 23, 2016 by cuzzy Quote Link to comment Share on other sites More sharing options...
dick Posted February 23, 2016 Report Share Posted February 23, 2016 Hi Geoff, if Dave has done ye magneto it will be right. Some carb settings attached, Monobloc first used on and#39;55 models (after Aug and#39;54), prior to that they were side mount float chambers. The and#39;55 settings should be near enough, looking at the jet sizes I think I would experiment with something a bit bigger. I understand Mono & Concentric sizes are the same. Dick. Quote Link to comment Share on other sites More sharing options...
dick Posted February 23, 2016 Report Share Posted February 23, 2016 No attachment! Give me an old bike any day! I'll try again, if it doesn't work my book quotes 210 main & 30 pilot. Dick. Quote Link to comment Share on other sites More sharing options...
stan wellback Posted February 25, 2016 Report Share Posted February 25, 2016 check float height first. easy on concentric. drop float chamber off, empty it, hold it level whilst it fills back up. it should stop with float sitting level, just proud of chamber body. petrol level about 4-5 mm below rim. the new pilot system on the premier uses new jets with different numbering. the equivalent to the old number 25 will be about right. If I had ordered a carb for this i would have said 3.5 cut away. 106 needle jet. 25pilot (new equivalent). are you setting it up for trials? the phrase "flat spot on acceleration" made me wonder. Quote Link to comment Share on other sites More sharing options...
stan wellback Posted February 25, 2016 Report Share Posted February 25, 2016 I should have pointed out to alter float level with the new style floats simply tweak the metal tang in the appropriate direction. Quote Link to comment Share on other sites More sharing options...
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