Hope you can help. I have brought a 1969 500cc Dommie, I took it out last week and it ran fine for 20 minutes, then cut out. It was very hard to restart. Before I start doing anything I did find the battery was 3 single cell torch like batteries they looked very old!!!, I will have to fit a new battery.
Hope you could point me in the right direction
Is that the correct year for your 500 Dommie, I thought they finished the 500 models in the mid 1960's?
If it is a magneto then you'll have to test if there is a spark when it cuts out, if not then I would suspect the magneto needs overhauling.
Is the battery a Cyclon cell type? They are costly and allegedly have a very long life. Google for more information. And test with a cheap meter before throwing it away. How wel is it charging?
Unfortunately, there are many possible causes of the symptoms you describe. When the engine cuts out, is it suffering from a loss of compression, and overheating? Does it start easily when cold? If so, it is possible that the wrong pushrods have been fitted. Mine were expanding, when hot, preventing the valves closing fully. A temporary solution is to increase valve clearance, when cold (try 6 thou. inlet & 8 exhaust). The motor may rattle a little, when cold, but quieten at working temperature. Weak mixture, and, or, retarded ignition timing, will also cause overheating.
If your bike is a '69 500cc it must be a mix of parts because no 500cc domis were made that year. Maybe it is a Mercury frame, which could have a '69 frame #, with an earlier 500cc motor. Anyway the most likely cause of your problem is ignition. Can't diagnose without first knowing if the bike has magneto or coil and points. If it has a magneto the battery is not relevant to the ignition system. Your symptoms sound like a magneto with a bad condenser, but obviously this does not apply if you have a coil and points
Hello the Last 500cc Dominator,s ever made were End of March 1966 and all these were model 88ss and all had Lucas K2FC magnetos if you have a magneto fitted your condenser is on its way out , or there is a blockage in the fuel line yours anna j
i am about to pull apart my dominators laydown gearbox (more neutrals than gears) . The gearbox is on the bench and ready. Any pointers gratefully received
Anna, when you actually ride your Dominator, instead of talking about it, you may find your comment somewhat simplistic. Very few, if any, of these machines (the best in their day) are still in their original specification. Problems arise now (partly due to various owners "improvements")that were unheard of when they were built. This, from someone who was actually riding on, in the 50´s.
What ignition is this bike running, magneto, coil & points or electronic ignition.
I have had 2 issues with bikes running and then cutting out only to then restart.
1. An over heating coil which allowed 100 yds of power before needing 10 mins rest.
2. A Boyer that overheated with a coil with the primary ohms just barely under the spec, again 15 mins cooling got 20 mins running.
1 Was fixed with new coil
2 Was fixed with a coil with 0.3 more primary ohms
...no one has mentioned blocked breather on the fuel cap?
Only me suffered this?
my mate fitted a tank bag on his triumph.....he had the same symptoms, it took us ages to find the problem!