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Re: Puch Acceleration Problem  Peter Staal
 May 06, 2002 15:26 PDT 
Hi Matt,
Since i haven't messed with a puch magnum/maxi in a long time i can't be
to specific on the clutch part....
 1. Acceleration - although the fastest I've had it is about 30mph on a
flat surface it takes a few minutes to get that fast. As you can imagine,
cars behind me are usually pretty displased by my slow start. Perhaps
this is a clue: it seems to accelerate significantly faster (and obviously
much louder) with the exhaust pipe removed.
A: if the pipe was working right, removal would cause performance drop.
So this pipe is
-wrong type ->replace (if original check next)
-clogged with exhaust tar. -> clean, depending on type: bad upto easy.
remove all parts (remove all nuts,bolds and screws on it, and tear it apart.
(exterior, dampers, internal housing whatever) -> remove all coal, tar and
oil deposits from the metal parts (remove, clean or replace the soft
parts -metal screen type of material can be burned clean), and put it
together again.
 
2. It seems to idle too high and wants to go forward even w/o me giving it
gas. I've played with the idle screw and reduced tauntness of
the throttle cable.
if the motor doesn't follow the idle screw's position, something else is
wrong.
If the idle speed (in rpm) is too high, auto-clutch engages (has to..) and
this forward thow is unevedible.
if engine rpm drops and it still engages, check clutch. (not common problem
i guess)
 
3. Some stalling, although I think this has more to do with a little bit
of old gas still being in the tank which was mostly burned up yesterday.
use fresh mix , before starting to modify some thing on the moped, old gas
can cause lots of trouble.
(checked for rusty flakes in the gas tank ?..and in the carb?. oil residue
build up in the carb?)
 
4. Starting is very sporadic. Some times I can pedal start it on the
first try, some times I ride down a street or two pedalling frantically
beforeit goes.
see quest. 3/5
 
5. Noise. My friend told me the timing may be the cause. This isn't
something I'm familair with, so any help would be greatly appreciated.
There is also a slight knocking sound at higher speeds, could although the
piston moves smoothly when I move the magneto by hand.
good (?) point that you mentioned the engines "smooth ness" , don't you feel
any resistance when turning over by hand, this means "no compression " (the
piston and cylinder are leaking some air) this is a serious performance drop
factor.
 
To be honest acceleration is really my biggest concern, followed by the
very fast idle. Also, can someone give me a brief tutorial on the purpose
of points, how to check and replace bad ones.
If your braker point settings are set wrong, performance drop and bad
starting habits are usual. And could explain it all too (exept the exhaust
thing).
Point checking can't hurt you anyway, ,
-remove casing, and you can check the gap space with simple materials, if
there is a hole in the magneto / flywheel . if not..trouble. if you have a
piece of metal or cardboard, with the pointgap ( not for sure, see manual,
is in mm 0.35-0.45) thickness, you can check the gap distance. by turning
the magneto round and observing the braker points, you can identify where
the gap distance is the largest. at this point this must be according to the
manual specifications.with the piece of metal/cardboard you can check if it
fits between the gap or has space left in between. If the points are damaged
(burned away, or center burned in) you can repair(make the contacts flat
again) or replace the things.
to modify : release screw , connecting braker points and ignition
groundplate , to enable rotation of one brakerpoint "leg ". and adjust ,
thighten(mild, but locked) screw again, re-measure distance , (redo 2x etc)
until satisfied. thighten screw complete , re-measure..
the other thing you can check is the motor timing. bit harder but
survivable.
You need to have special equipment (measuring tool) to do this, never the
less you have to check the points first, and clean the exhaust. so i'll hear
where it ends. And if more care is needed.
High rpm , and bad starting could also be caused by crackcase leaks,
(failing oilseal of the crackshaft). harder to check....
Peter
 
Thanks in advance,
-Matt
 
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