Just purchased a mid 1980 Mz 250 single collected it yesterday disk front brake started first kick after going through the MZ start procedure 40,000 miles on the clocks yes it has a speedo and a rev counter I have often wondered what a minimalist bike would be like single two stroke will not work with anything less I need to get it Mot before i hit the road and as i have six bikes I think my R65 Beemer has to go as I can only get 4 on the insurance Now does anyone out there have any experience of these machines i did a quick look through the forum but did not find any reference to them I am really looking forward to going out all though here in the UK the outside temperature is now below 0 deg centigrade it will take me back 50 years to my first bike a £ 5 Francis Barrnet that i purchased at 16 all that did for me was a 5 mile trip to the local Honda dealer where it turned into the deposit for a £220 Honda CD175 loved that bike fetching ridiculous money now Ps still working on the Honda CB250 RSA Trev
Heres some resources I found for the MZ https://www.2fiftycc.com/index.php?resources/categories/mz.82/
What a bugger this bike turned out to be talk about spending on it points air filters new seat unit Main problem was with the carburation The first carb it came with was awful it would not tick over and over run was awful excessive fuel and stuttering Purchased a second carb well that,s a lesson on how to waste time it would not start or run turns out it was a china copy with badly drilled airways etc the dealer to be fair gave me the money back and told me to bin it 3rd carburetor would not start turns out the choke mechanism had fallen apart there is a blanking rubber over the choke jet that had welded down took it apart obtained a new unit it now runs had one small run just to set it up and to be honest its quite a charmer Now to get on wityh the paintwork Trev
i normally turn of the fuel supply to the carb while the engine is running This i did and noticed the idle sped increase before the engine cut out does this mean that the fuel level is to high in the float bowl Trev
I wonder is their a device or way of adjusting the float level while the bike is running i can imagine a remote float bowl remote sensor that controls fuel flow any one out there done this ? Trev
when you turn the fuel off the mixture leans out anfd the motor revs higher before it cuts out. also happens if you do a crank seal. try it with a 2 stroke lawn mower.
What do you mean if you do a crank seal ? I have replaced crank seals in the past when the engine would not idle to me the seal fail would weaken the mixture Now of course the fuel rate must be able to supply the motor under higher revs and loads and there is a chance of running lean if the float level is to low Trev
when the fuel supply is turned off the fuel becomes less and as such the mixture is leaner. as this happens on a 2 stroke the engine revs rise and as the fuel ceases the motor stops.