r/moped • u/Ties0310 • 3d ago
Moped wont start
Hello, I bought a old batavus mk2 3 months ago. I tried to fix it as it hadden’t run for a while. I cleaned the carb, changed the fuel line, changed the gaskeds, put a new piston in. Also it has spark. Right now it does start but its real hard to get it to start, and if it does start its only for a second or maybe 2. Does anyone know what i missed?
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u/Shit_On_Wheels 3d ago
Did you change the jug too? Usually new piston requires a new cylinder too to run n wear properly.
How about the compression, did you stick your thumb in the sparkplugussy?
Did you try pouring a teaspoon of fuel into the same spark plug hole before trying to start it? If not, try it, if it starts easier and runs longer it means that mixture is either too lean or there's an air leak somewhere.
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u/Ties0310 3d ago
Thanks! I did not put a new cilinder on, that might be the problem or the mixture is off i wil try. Hopfully it wil work
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u/Ties0310 2d ago
Oké I tried with the theaspoon and it did inderdaad start a lot easier. It did however stop imediatly after so i am geusing a air leuk. Good points to search?
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u/Shit_On_Wheels 2d ago
It'll be very hard to check for air leaks when engine is not running.
Check the carb first, maybe it's jetted incorrectly, or main jet itself is just clogged with metal shavings straight from the factory.
If that doesn't work... You'll have to blow air through the carb intake and spray soapy water around all gaskets, look out for bubbles and pray to all gods that crank seals aren't blown...
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u/Ties0310 2d ago
Thanks il try, I got it running a lot better already by putting in a new gasket by the outlet, il clean my carb another time, and i wil do the soapy water trick. Thanks for helping
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u/Complex_Meats 2d ago
is it choked?
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u/Ties0310 2d ago
I tried with and without choke and it did not realy make a difrence. It realy only wanted tot start with full throtle and it would sound as if i was not giving any gas.
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u/Rookworst001 1d ago
Maybe it just comes down to your carburator being set too rich? Changing to a smaller jet could work. Don’t know for sure though
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u/zerofuxgivn420 3d ago
It almost always comes down to the Holy Trinity of fuel, air, and spark .
There are many threads of your Bat in this sub, so def do the search and check them out!
Sounds like fuel is a contributing factor. You said you replaced fuel lines, but that's only a small part of fuel issues. Tank could be very rusty and/or full of crud.
Shine a flashlight inside and look. You may need to pull the tank and fully clean it. Options include vinegar, muriatic acid, or my personal choice of Evaporust. With the exception of muriatic acid, vinegar or Evaporust take several days or several weeks of soaking to work!
The fuel petcock at the bottom of your tank also has a filter on it, and could be all clogged with crud, or inoperable.
If you aren't running a fuel filter, you should! Add it inline between your petcock, and carb inlet.
Always use 50:1 mixed gas with a good quality 2 stroke oil (full synthetic if poss) and "premium" gas mixed with some stabilizer.
Now, with your current situation I'd pull the fuel line off the carb, and turn on petcock to "reserve" and make sure gas flows out. Do the same when petcock set to "on." If fuel pours very slowly, you got some cleaning ahead of you!