Hi everyone.
I have a 1993 MZ301e project bike. The 301 motor was in pieces when I got it and there was no carburettor. I rebuilt the motor with new bearings, seals and a rebore but was not sure what to do about the missing carb.
There seems to be good and bad stories about pattern Chinese carbs so I decided to bite the bullet and bought and fitted a new genuine Bing 84/30/110 made in Germany carb – the carb that it would have been fitted with when new.
Following the usual MZ starting method of fuel on, hold the choke lever open, kick over a few times, ignition on and it fired up first time, so far so good.
It then stopped and after trying repeatedly I found that it will only run for a few seconds after using the choke. If I hold the choke open slightly it will keep running and rev freely.
As I understand it (after searching on YouTube!) if a motor will only run on choke then there is a problem with the pilot jet, so I removed the carb, stripped it, checked all the jets and sizes, needle, needle position and float height against the manual and have blown all the bits out with a compressed air but it still will not run.
With messing about with the settings I have found that if I get the motor warm by keeping it running by holding the choke open and the air screw fully screwed IN, it will just about keep running.
I have already checked obvious things like the petrol tap works fine and fuel flows into the float bowl, the tank lid vents OK, the generator/ignition parts are all pinched from a working ETZ250, the timing is correct and the spark plug is a Brisk one as I have used in other MZs without any issues.
Can anyone suggest what the problem might be, before I give up and try a Chinese BVF or rummage about in the scrap bin for any original BVF remains?
Thanks Andrew Staley