vacuum clogging up.

hi, I had this problem last month it lasted 2 or 3 days then all of a sudden it ran fine again. but this problem has just re occurred. when I put my foot down I don't have my full power and you can hear it struggling to keep the revs up. they drop and bounce around a lot causing it to be a very uncomfortable ride. the pipes leading to the airfilter from the vacuum was clogged with oily sludge. I removed the pipes and cleaned them out but am struggling to get on the bolts that hold the vacuum on. anybody done this before that could shed some light on why this is happening, or got any tips?

thanks in advance for any replies.

The air filter pipes are the breather form the crankcase etc so will be sludgy. Sounds more like a blocked fuel filter or dodgy fuel hoses to me. What engine carb/injection are you running?

its a 1.2carb

I have checked the fuel return pipe and it seems to have a strong pulse back. I have never checked the return pipe before though so have nothing to compare with. but it was definitely more like a pulse rather than a flow. is this right? I also took my spark plugs out which I have only just replaced a week ago with brand new ones and they were extremely black and oily. ?? anybody got any ideas of whats going on in there?

I have also just took the vacuum off and cleaned it out thoroughly and still the same problems? don't know what else to do. anybody?

sounds like its over fueling might be worth stripping the carb down and cleaning it thoroughly and make sure the needle valve is working properly.

If plugs are black and oily definatley over fueling some where,best clean carb out fully as mentioned above

ok thanks. ill let you know what happens tomorrow

does anybody know if the fuel pump should be pulsing the fuel back through the return or if this should be a constant flow?