MZ500 - carburettor

[madoc]

I have a silverstar
It came with the standard exhuast, which muted all engine noise.
I could not find another system (a potential problem in the future) so I knocked a couple of holes through the baffles.

Better noise.
I did the usual of up jetting (the Dellorto, in this case) by about 10% across the range as a starting measure, which seems to have done the job in the midrange and at wide open throttle.

Trouble is that I'm not having much luck on curing the really bad backfires on the overrun.
I went up to an idle jet of 50 (from the standard 45), then to a 60 and now to a 75 ....
Either the carb was incredibly lean jetted to start with (and it was very hesitant below 3k revs, before I started this) or I am missing something.

The carb doesn't spit back on take up and falls back onto idle cleanly.
The issue is only when shut off fully, on the overrun.
I can cure it by using a bit of choke (starting jet actually on the dellorto) via the handlebar graduated control, which indicates that it must still be lean. However, any sort of choke (at idle) on a warm engine will instantly kill it.

There are no exhaust leaks or induction leaks that I can find.

[DAVID THOMPSON]

mine is a 1995 Saxon Tour with a bing and i find it to not have much power below 3800 rpm
it runs ok 4000 and up from 2000 to 3800 its a big underpowered MOPED
and as with most German bikes stock gearing way to tall for those of us that do not have the autobon
dave