78 Sachs won't rev without choke

My 1978 Sachs Westlake with a 504 engine will not rev without the choke, it idles fine, but if i try to rev the engine it bogs and dies, but doesn't bog or die when i have the choke on and rev it. I'm new to mopeds, and i need help to get my ped running well! Any ideas of what's wrong with it, or something i can do to fix this?

Re: 78 Sachs won't rev without choke

All stock right?

Check for air leaks n stuff. run it. srpay everywhere sept the intake with carb cleaner or something. wait for it to stall or idle diff.

Re: 78 Sachs won't rev without choke

♣Slew Foot♣ /

it needs a restrictive airbox. if you do not have one and do not want to spend over 50 bucks for an airbox and stock filter. see pic

22 oz soda bottle with a 4'x4' square of 222 mesh mono filament nylon silkscreen, with a pen tip mounted on the top side, so it doesnt hit the sidecover as a intake limiter. pack the ends of the screen in first, so it can not be sucked into the choke/intake.

no luck finding a 22 oz plastic bottle? a lipton leaf tea square bottle will work, with no hole or pen tip and you have to make sure the screen is wrapped around the intake/choke as to not interfere with choke operation. Make sure the ends are way away so they can not be sucked into it. the air leaks around the bottle and square plastic carb piece is just right, if not tinker with a small hole 1/32" and work your way up.

each time you tinker with the airhole re adjust the a/f mix screw, till she purrs.


Re: 78 Sachs won't rev without choke

or you could have a clogged/ dirty main jet, take the carb apart and clean it out. take out the main jet , hold it up to light and look through it ,see if it is open and clean.

Re: 78 Sachs won't rev without choke

Jeb Zinewicz /

Going through similar issues with my bike, though mine has been moded. Definitely are air/gas issue. Either needs less air or more gas. Check for air leak first, maybe gaskets too?

Re: 78 Sachs won't rev without choke

Lance applewhite /

The exhaust port and muffler may be plugged with carbon deposits.

Re: 78 Sachs won't rev without choke

check for clogged jet first! it's probably it.

almost always is. shit damn.

it's easy to forget how often that's the problem once you've fixed it a few times and you start running in-line fuel filters

as a result asking a bunch of salty vets you get alotta answers about everything else that could be wrong, which are all fair, but clogged jet is by far the most likely, followed by bobdob's insistance that you need a filter and the possibility of airleaks, muffler is possible too but not probable.

clean your carb dog.

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