Vintage Vespa Forum

Already tried to help with start pilote before pedalling ?

I guess i don't understand...

Well, i finally got smart and did a compression test this morning... 60 PSI Maximum.. I made sure the decompressor valve was fully closing too, and i hear no air leaks around the head gasket. So it's gotta be getting by the piston. Guess the cylinder wasn't as good as it looked.
i know 2 stroke chainsaws need at least 95-100 PSI to fire... so i assume its the same on here.

Hi, The best you can do is change the cylinder and setting the pistonrings with the right clearance in the cylinder....

That's what I figured... MopedDivision has a cylinder kit for it I can buy for $105.00 usd.
Thanks tony!

Travis , let me know when it's fitted !

Will do!
I had to contact my brother in law to be sure the price was ok, haven't heard back yet.
Also dealing with the loss of a pet now.

got the cylinder kit in from Moped Division today, pulled the engine and replaced the cylinder,piston and rings , gaskets. the motor feels much better turning over by hand...
Now to set the motor back into the frame!

Still wont start, compression is good now, spark is good and blue, its getting fuel....
Edit: my dad came out and helped me , he got it narrowed down to fuel mixture, it fired a few times...... anyone know how many turns out the speed screw is supposed to be?



Edited 1 time(s). Last edit at 2020-08-05 08:23 PM by TCM3.

Hi , what do you mean by speed screw ? picture ?

sorry it took me so long to get back to you,. the screw i am referring to is just below the fuel fitting in this picture with the spring on it..... It's really more of an minimum idle adjuster.

I don't know what to do with this demon of a bike.....
I ordered a new airbox due to the old one being cracked around where it clamps to the carburetor, fits good.... but it wont fire, to me it really smells like its rich, but the other day a test we did by placing paper towels over the intake to block out excess air and it fired up for a bit, which that made me think it was running lean to start with, but after peddling for a few seconds, i smell gas which makes me think its running too rich, yet the symptoms say it's running too lean to even start.... i guess i may replace the crank seal next as i ordered a new one.



Edited 1 time(s). Last edit at 2020-08-24 04:17 PM by TCM3.

Hello, the screw you mean is the idle screw. turn it in to the moment that the throttle goes in movement + a little bit more +/- a third of a turn. The moment the motor runs, change the rpm's by adjusting this screw.....in= more rpm's....

the only problem is that is the only the screw on the carb.

Well, i think i'll go ahead and replace that crank seal. If it put starting fluid straight into the cylinder it will puff puff, like it's very lean. We'll see....