Vacuum leak?

[twist]

Hi Guys,

So I replaced the petcock and fuel/vacuum lines. My Spree is getting gas, spark and has decent compression. It still won't start, do you think it could be a vacuum leak? The starter runs, but the engine will not even pop.

Thanks for your advice.

[bradthreee]

The only was to really know is to do a compression test

[j_brawner]

So what is the desired compression reading? On an 85 Aero 50 i tested it today and was getting aorund 35 PSI. Is that about right or is that weak? The bike was running great and then suddenly stalled out and hasn't fired since. Been through carb completely.. ( several times) New plug, looked at cylinder, nothing looks suspect, head was normal looking, head gasket was fine. Has vacuum pulling gas through carb, has spark, has compression (around 35 PSI) why wont it go?

[Wheelman-111]

Greetings:

35 is way low. It's probably too low for the reeds to be the problem. More likely cylinder/ring seal. Possibly bad crank seals.

Pour a teaspoon of GN-2 down plug hole and retest if you like. If it goes up to 90 it's probably rings. If it goes to 40 look for oil behind the variator and/or alternator.

[bradthreee]

I hate to bust a Kenny on you but clean the carb. If you've cleaned it as much as you possibly could try boiling it in one of moms old pots! Hey it worked for me