leigh enfield Posted April 10, 2009 Share Posted April 10, 2009 Hi, after about 1.5 miles(when hot) my 1966 2a begins to misfire and continues to do so, although will still reach 50 mph ok. I've changed various parts, condenser, checked timing, changed fuel lift pump, changed coil. I've not done compression check. Timing done with strobe. Sounds fine when cool. Choke does not seem to make any difference to the misfire. Any thoughts, many thanks, Leigh Quote Link to comment Share on other sites More sharing options...
jimmy_neutron Posted April 11, 2009 Share Posted April 11, 2009 cool name The list is endless as you probably already know. Incorrect or degraded ignition coil. Ht leads breaking down which is reasonably common cos 'they don't make em like they used to'. Fuel line running too close to the exhaust. Quote Link to comment Share on other sites More sharing options...
secondjeremy Posted April 11, 2009 Share Posted April 11, 2009 It can even be something like damp in the distributor which evaporates and condenses in the cap as the engine warms Quote Link to comment Share on other sites More sharing options...
jimmy_neutron Posted April 11, 2009 Share Posted April 11, 2009 Best thing to do is probably fill in ur location in ur profile. Someone may take a quick peek at it for ya cos ya never know ya luck. Quote Link to comment Share on other sites More sharing options...
ThreeSheds Posted April 11, 2009 Share Posted April 11, 2009 For me these are the pertinent comments: Sounds fine when cool. Choke does not seem to make any difference to the misfire. You don't mention plugs - have you changed or had a look at them? I am thinking that there may be a damaged plug (for the cost of them it is worth replacing them anyway) or perhaps there is a problem with the carburettor (main jet popped out or something?) and it is running very rich? The above both happened to me in my early years with motorcycles, along with plug leads/caps breaking down (as mentioned above) and all of these caused hot misfire, so I think that would be the area I would look next. Roger Quote Link to comment Share on other sites More sharing options...
leigh enfield Posted April 11, 2009 Author Share Posted April 11, 2009 thanks folks. Already changed: leads, points, spark plugs, coil, wrapped up fuel pipe to see if over heating was the issue. If it is heat related could it be sticking valve or valve related? I have tried pulling off lead from rear spark plug and it seems not to make any difference to running sound when stationary. thanks, Leigh Quote Link to comment Share on other sites More sharing options...
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