MZ RT 125 (4T)

[Steffan]

Right, getting a bit hacked off with this one.
When I got it was a skanking but with TLC it has improved but still won't idle.
Starts OK on the choke (new cable)
Won't rev initially on choke (OK can live with that)
Then will only start on half choke but will rev on the throttle but dies like a dead thing once the choke is knocked off.
Anyone any ideas - actually I am thinking that the logical place to start is with the mixture and throttle stop....

But any H&Ts or encouragement not to burn the bloody thing would be most welcome.

Steff

[SteveC#222]

Sounds like a problem with the pilot jet system as this effects the first 1/4 throttle response. It might be a partially blocked jet or one of the internal airways in the carb body that is blocked - it doesn't take much. You may also need to check the setting of the idle mixture screw if it has one. I'd take the carb off and give it a damn good clean and blow all the airways/jets through for starters.  If it's ever been standing for any length of time any petrol left in the float bowl will go off and can leave a varnish on the jets which effects the amount of fuel they let through and as the holes are tiny this will mess up your carb.  Also check you haven't got any water/crap in the float bowl.

[Richard]

Don't burn it, it's a lovely looking machine (though perhaps not in the dining room come Christmas or Ruth will certainly have something to say).

I agree re the pilot jet rather than the main.  Have you taken the carb off and blown through the various jets.  Its been standing a while so some of the fuel may well have jellified - you saw my carb that did that - and gunged up some of the smaller passages.

Get a couple of tins of carb cleaner too and blow through with that ?