After all my efforts rebuilding my 9E I attempted to start it on the bench today , all temporarily wired and fueled, it has a great spark and good compression but It coughs and splats and will not run. Timing is spot on. I can only imagine its the carb, its one that had stood for years, I have cleaned it as best I can but maybe there is a passageway blocked somewhere. Any Villiers 25S carb experts out there? What should I be looking at?
I learnt a great trick for cleaning carbs, I tried it out on one of the moped carbs and it works a treat! Helps if you clean as much as you can, speeds up the process, but sounds like you already have.
Take an old pan, like the one you boil eggs with, and fill it about 1/5 lemon juice, and about 2/5 water.
Start putting it on the hob, on high, while you dismantle the carb. Remove all rubber parts, you could damage them. Also, I have to say this process removes paint, so if you have a metal air filter you wanted to degrease, either don;t, or it will need a respray.
When you're done, put all of the non rubber parts of the carburettor in the pan. Best results when "violently boiling" but of course contorl the heat to not boil over.
After about 10 minutes (mine was quite crappy), have a look at it (yours may take 5 minutes if it's already been cleaned), and if it seems OK, rinse in water (with washing up liquid to remove all of the lemon juice). It should look matt aluminium colour.
Result in a picture:
http://i29.servimg.com/u/f29/13/39/38/65/125_xl64.jpg
Hope it helps, JP