mz 125 sm problem/carb

[Mzedian]

wondering of anyone can help me with this problem, basically I have installed a 'universal' exhaust on my bike to add abit more sound as well as performance, but recently the bike has been running abit funny, when going along at higher speeds, once you change gear it bogs down then picks up again but does this when your 'giving the beans' but it also happens every now and then whilst cruising, I believe it to be the carb as that seems to be the only explanation as I haven't re jetted since putting it on and now there is more air being pushed out, so it may need more fuel? But also I had a problem with the carb overflowin. I presumed this to be the float and had it changed but this problem has not gone away as I notice every time I stop there is fuel on the floor from the overflow pipe on the bottom of the carb.
Can anyone give me any ideas on how to resolve this problem as I wanted to have the bike running nice and smooth again
Thanks.

[DAVID THOMPSON]

lots of luck on finding jets better to put the stock pipe on it if it is serviceable..
the factory had these tuned to max and trying to get more usually results in bad running and bad gas milage

and a carb clean up and float adjustment is needed
the shut off needle is not shutting things off

use gas with no ethanol
look up your state and city at
http://pure-gas.org/
it may not go faster but it will run better
dave

[Mzedian]

Thanks for the reply will get into it, thanks

[stephendacosta]

Having ten 125MZ's, I can attest to the stock muffler working best, even when a free flowing can has been properly jetted for. Tried at least 5 other options with inferior results.
A few of mine will reach 130 km/hr down hill with a stock muffler. A couple of them wanted one size up on the main jet. A weak running bike usually needs cam timing.
Like Dave says, the float needle isn't seating; usually a good cleaning will remedy the drip. Make sure the petcock is off when the engine is off.--Steve