corvairbob
New Member
hi all. i have my neighbors suzuki fa50 moped on the bench with running issues. now i a bit familiar with 4 stroke engines and i have built more than my fair share of car engines and a few small engines, however, i have not had much bench time with 2 strokes so let me list what i have and have done
took the carb off and cleaned it and blew air thew every port i could find. then i took compression and cranking by hand not foot i get 50 psa if i use the drill on the flywheel i get just about 90 psi so i got new rings and still have almost 90 psi yes honed the cylinder with a good crosshatch. i put the red bad ring on top and the other rings with the expander band on #2 if wrong let m know. i did not see any particular upside the the rings.
i got another reed valve body and petal the petal looks good and set on the block real nice.
no breather yet it is not spitting gas out of the carb with this reed block like the original one it did.
the cylinder base gasket and head gasket and rings are new.
the slide main jet pin is on #2 notch from the top of the pin.
it appears that i can't make much of a change with the air jet. and i have to have the slide idle adjustment turned way in when i have it running it will idle at what sounds like 2000 RPMs and then it will start to get slower and finally stops if i do not give it gas. it starts with the choke and i can shut the choke and it will run so that must be doing something.
so how much compression should i have? some on the moped army says 150 psi but that sounds like a lot for a 2 stoke 50cc engine. i did to the best that i could to make sure the rings were at the pins when i installed the piston. but i guess i can remove the piston again and make sure i did not bust a ring. if i did then those piston ring alignment pins may be worn to the point they are not keeping the rings in position. i guess they have to be there to keep the rings from catching the ports.
i do not think the timing is off but if it is what is the best way to check the timing? i have an induction timing light and i guess i can power it with a small 12-volt battery and clamp it on the plug wire and check the timing but because i can't hold the idle it may be hard to get a good reading. so is there a good way to set the timing static with the piston at tdc? i can take an old plug and put a bolt in it to set the tdc and see if the timing marks are ok. if i do that should the piston be right at tdc or a bit early?
well that is quite a bit of info so maybe a new carb, setting the timing if i can get that info, and what i should be seeing for compression with a drill on the flywheel? maybe 1000 RPMs? thanks
took the carb off and cleaned it and blew air thew every port i could find. then i took compression and cranking by hand not foot i get 50 psa if i use the drill on the flywheel i get just about 90 psi so i got new rings and still have almost 90 psi yes honed the cylinder with a good crosshatch. i put the red bad ring on top and the other rings with the expander band on #2 if wrong let m know. i did not see any particular upside the the rings.
i got another reed valve body and petal the petal looks good and set on the block real nice.
no breather yet it is not spitting gas out of the carb with this reed block like the original one it did.
the cylinder base gasket and head gasket and rings are new.
the slide main jet pin is on #2 notch from the top of the pin.
it appears that i can't make much of a change with the air jet. and i have to have the slide idle adjustment turned way in when i have it running it will idle at what sounds like 2000 RPMs and then it will start to get slower and finally stops if i do not give it gas. it starts with the choke and i can shut the choke and it will run so that must be doing something.
so how much compression should i have? some on the moped army says 150 psi but that sounds like a lot for a 2 stoke 50cc engine. i did to the best that i could to make sure the rings were at the pins when i installed the piston. but i guess i can remove the piston again and make sure i did not bust a ring. if i did then those piston ring alignment pins may be worn to the point they are not keeping the rings in position. i guess they have to be there to keep the rings from catching the ports.
i do not think the timing is off but if it is what is the best way to check the timing? i have an induction timing light and i guess i can power it with a small 12-volt battery and clamp it on the plug wire and check the timing but because i can't hold the idle it may be hard to get a good reading. so is there a good way to set the timing static with the piston at tdc? i can take an old plug and put a bolt in it to set the tdc and see if the timing marks are ok. if i do that should the piston be right at tdc or a bit early?
well that is quite a bit of info so maybe a new carb, setting the timing if i can get that info, and what i should be seeing for compression with a drill on the flywheel? maybe 1000 RPMs? thanks
