Suzuki EN 125 losing power

[paulhanle]

Almost definitely due to carb diaphragm split, I serviced my latest purchase , bought a new inlet manifold as bike was running too weak ( no mixture adjusting screw on mikuni carb ) scratched my head a little , bike was flat out at 55 mph , fresh plug new oil and air/fuel filter no change , stripped carb , found replacement diaphragm for £10 instant power increase to 70 mph on the flat

[paulhanle]

Next step now it's up and running correctly is to fit a 115 main jet , ditch the standard air filter for k&n type that's about all you can do to these 125 single 4 strokes , I once did this to a cg 125 made it much more rideable with more get up and go off the mark ,

[fastbob]

Happy days! Good to hear about a positive outcome for once.

[tomh65]

Thanks Paulhanle. After so many weeks of poor performance, I took out the carb and replaced it with a new one. Sure enough, the diaphragm was perforated. It had about 12 holes in it. Now it runs like a 250. I can get up hills in 5th gear - no problem. There was one tiny problem though - the fuel pipe into the carb had rotted. I left the bike in the garage overnight, only to find that it leaked all over the floor. Over 2 gallons of petrol wasted!! I should have replaced the pipe at the same time, but we live and learn...