On The Pegs April 2019 - Volume 4 - Issue 4 | Page 66

On The Pegs
DIGGING DEEPER...
RUSS’S JETTING
(@60 DEGREES F)
MAIN JET - 440
IDLE JET - 25
NEEDLE - 43-75 (2ND POS FROM TOP)
AIR SCREW - 2 1/2 TURNS OUT
NEEDLE JET - STOCK/S4
ENGINE
The engine is stock, but I put a yellow power valve spring
with it at flush setting. That’s the stock spring, but I opened it
up quite a bit so it changed where the power valve opened up
and made it a little more responsive.
I’ve played with the jetting a ton, but still using the same jet
kit that came with the bike. One of the biggest things I found
for riding this thing aggressive, that was a super sneaky way
of making it run better up top was to put a 250 SX CDI box on
it. It really helped the mapping. When you are trying to build
power or trying to hold it wide open, the XC CDI seemed like it
wouldn’t allow it to rev to a certain range I wanted it to go to.
The SX box let me rev it a little further.
93 with Motor X, cross power 60 to 1. Motor X gear oil. I don’t
have a fan on here. Twin Air air filter. Aluminum cage.
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