PW-JETTING
STORMBR...@webtv.net
very good and want to jet it a little leaner. Any advice to make these
little things perform a little better. Or where to get that new gear for
low end speed?
F4BikeNuts
Main 70
Pilot 40
Needle 3X1 in the 2nd clip
Float height 16.5mm
>My son's will not clean out
>very good
Neither will mine, but since the kid won't ride it, I haven't messed with it!
>Any advice to make these
>little things perform a little better.
I've heard disconnecting the autolube pump and running premix helps a lot.
Also, make sure the exhaust restrictor (a washer) is not installed, and the
throttle restrictor is opened up or removed.
-Chris Orndorff
F4Bik...@aol.com
KTM crasher
size smaller on the main jet. Some parents had replaced the stock air
filter assembly with a uni-filter that was held on with a radiator clamp.
Don't do both of these as the engine will be too lean and seize!! I also
removed the auto-lube pump (a shop in So. California called PAX Racing used
to sell a metal cover that popped into the opening) and used pre-mix. There
is a diode (?) in the electrical system that acts as a rev limiter, I only
had to cut the wire on that. Yamaha sold scooters that used the same shaft
drive as the PW series, they did sell different gearing as well. When I
first bought the PW it ran like crap, I tried different jetting took it
back to the dealer etc. no one could locate the problem. It finally siezed
up - the problem was the intake manifold that the carb bolted to. Some one
at the factory didn't inspect the intake manifold - there was a piece of
flashing in there that only allowed just enough fuel/air mixture through
for the bike to run. Yamaha customer service was great and replaced the
whole top-end for free! There is a guy on here (RMD) who goes by SXFANS. He
may remember the name of an independent shop on Sierra Highway between
Lancaster and Palmdale CA. The owner knew all about PW's and used to build
the unlimited PW's.
Ed Morris
KTM250EXC
STORMBR...@webtv.net wrote in article
<25614-37...@newsd-253.iap.bryant.webtv.net>...
TSMaxel
(F4BikeNuts) writes:
>
>>Anyone know the stock jetting on a PW-50?
>
>Main 70
>Pilot 40
>Needle 3X1 in the 2nd clip
>Float height 16.5mm
>
>>My son's will not clean out
>>very good
>
>Neither will mine, but since the kid won't ride it, I haven't messed with it!
>
(I live in Ohio)
Change your main (I use a 60 main) and adjust the needle depending on your
area.
If she loads up at idle, just go to a 30 pilot.
>>Any advice to make these
>>little things perform a little better.
>
>I've heard disconnecting the autolube pump and running premix helps a lot.
>Also, make sure the exhaust restrictor (a washer) is not installed, and the
>throttle restrictor is opened up or removed.
>
Perform better?!?!?! This winter I will tear into Tanner's PW and make it run
as if it were Tyler's PW he had a few years back. Tanner is not ready for a
ripping maching, but a good performing bike will be no worst than the stock to
a beginner.
Mill the head .080. This will add major compression and give the bike some
pep.
Find an old Yamaha shaft drive moped at a junk yard and buy it for $50. All
you are after is the drive shaft and pinion/axle. swap these out for the PW
and now you will have the top speed you will need to go fast (I have one in the
garage that will probably wait another year.
As for the clutch... Just change the fluid often and run ATF. The clutches in
these bikes seem to last forever.
As for disconnecting the oil pump... I have never done this and my son won
plenty of races on the PW. Keep the pump clean and adjusted (the arrow and the
mark lined up) and it will work just fine.
TMax
'94 RM 250
'97 RM 80
'98 RM 80
'99 PW 50
J Payer
> Mill the head .080. This will add major compression
> and give the bike some pep. Find an old Yamaha shaft
> drive moped at a junk yard and buy it for $50. All you are
> after is the drive shaft and pinion/axle. swap these out
> for the PW and now you will have the top speed you
> will need to go fast (I have one in the garage that will
> probably wait another year.
Ah-hah! Soooooo, you're the dad who always installed the ball bearings
on the pinewood derby cars and would the living crap out of me at the
races! :-)
J&K
Special thanks to the following:
Jim Cook at www.Smackovermotorsports.com Jeff at www.mxsouth.com and
John Duffy at www.appliedrace.com
TSMaxel
Payer) writes:
>
>Ah-hah! Soooooo, you're the dad who always installed the ball bearings
>on the pinewood derby cars and would the living crap out of me at the
>races! :-)
>
<LOL>
Actually, we rode the PWs against the KTMs and Cobras. 8-) People would SH!T
now days if they didn't have the injected class.
However... ;-)