XS650 Direct

Dyno Tune Needle & Jet Kit for Mikuni BS34 CV carbs as used on North American
model 1980-84 XS650's.
Kit smoothes out the powerband and removes the midrange hesitation and leanness
resulting in a smooth acceleration from idle thru redline.

Kit Contains: 2 slide needles with clips
2 pilot jets
4 main jets (2 sizes)
1 Drill bit to modify slide
Instructions for tuning with various Exhaust & Carb/Intake setups

Slide (Jet) Needle - 4JN19 - Fits: XS1/XS1b/XS2/TX650 (1970-73) Stock Mikuni
BS38 CV Carbs.

Needle Jet - Z6 - Fits: XS1/XS1b/XS2/TX650/A/XS650B (1970-75) Stock Mikuni
BS38 CV Carbs.

Slide (Jet) Needle - 4N8 - Fits: TX650A/XS650B (1974-75) Stock Mikuni BS38
CV Carbs.

Needle Jet - Z 8 - Fits: XS650C/D (1976-77) Stock Mikuni BS38 CV Carbs.

Slide (Jet) Needle - 4M1 - Fits: XS650C/D (1976-77) Stock Mikuni BS38 CV -
Carbs.

Needle Jet - Z 2 - Fits: XS650E/SE(1978), XS650F/SF/2F(1979) Stock Mikuni
BS38 CV carbs.

Slide (Jet) Needle - 502 - Fits: XS650E/SE(1978), XS650F/SF/2F(1979) Stock
Mikuni BS38 CV Carbs.

Needle Jet - Y-O - Fits: XS650G/H/SH/SJ/SK/SL (1980-84) Stock Mikuni BS34
CV Carbs.

Jet Needle - 5HX12 - Fits:XS650G/H/SH/SJ/SK/SL (1980-84) stock Mikuni BS34
CV Carbs.

Note - now use improved Needle Jet #48-0663.

Jet Needle - 5IX11 - Fits:XS650G/H/SH/SJ/SK/SL (1980-84) stock Mikuni BS34
CV Carbs (originally used in 1980 Canadian model BS 34 CV carbs).

Note the needle clip adjustment grooves.
Needle profile is Richer running than 5HX12.

Needle Jet 336-Y0 Fits: XS650G/H/SH/SJ/SK/SL (1980-84) stock Mikuni BS 34
CV Carbs (originally used in 1980 Canadian model BS 34 CV carbs).

Matches Jet Needle - 5IX11 - and provides richer running than standard Y0 type.

Spring - Slide needle preload spring for stock BS34 CV Mikuni carbs as used
on 1980-84 North American model XS650's. OEM Ref.# 3F7-14589-00-00

This spring holds the slide needle down in place in the carb slide.

Carb Slide Needle Clip (pk./2) - Fits: Slide Needles on 1974-84 650's
with stock Mikuni BS34/38 CV Carbs.

Slide Needle Washer

Washer - Fits under slide needle preload spring and on top of needle & clip on
stock BS34 CV Mikuni carbs as used on 1980-84 North American model XS650's.

O-Ring - needle jet (nozzle main) - Fits: XS/TX 650's (1970-79) with Stock Mikuni
BS38 CV Carbs. If this O-ring is dried out, shrunk or damaged, fuel can pass
around the outside of the Needle jet instead of just thru the jets center causing a
richer carb fuel mixture. Note: O-Ring appears too small but it is correct, install
by carefully stretching with pointy needle nose pliers until it just fits over the jet.

Fuel Idle Mixture Screw - (256 type) - Fits:XS1/XS1b/XS2/TX650/TX650A/XS650B
(1970-75) with Stock Mikuni BS38 CV Carbs.

Fuel Idle Mixture Screw - (584 type) - Fits: XS650C/D (1976-77) Stock Mikuni
BS38 CV Carbs.

Fuel Idle Mixture Screw with O-Ring - Fits: XS650E/SE/F/SF/2F(1978-79) Stock
Mikuni BS38 CV Carbs.

Beware!
Carb idle mixture screw O-Rings included may or may not fit correctly in your
Mikuni BS38 CV stock carb. The O-Ring in the carb as originally supplied by
Mikuni/Yamaha varies in fit and size and we have found it impossible to match
or guarantee a proper fit. No alternatives can or will be supplied. The mixture
screw and matching O-ring was never sold or supplied by Yamaha or Mikuni.

Fuel Idle Mixture Screw with spring, washer and O-Ring - Fits: XS650G/H/SH/
SJ/SK/SL (1980-84) with Stock Mikuni BS34 CV Carbs.
See following 48-5012 text.

Mixture screw Kit - Mixture screw Washer, O-Ring & Blind Plug - Fits: 1980-84
XS650G/H/SH/SJ/SK/SL Stock Mikuni BS34 CV Carbs. Plug covers vertical re-
cessed idle mixture screw & keeps out contaminants. O-Ring fits under metal
Washer at bottom of mixture screw hole and the engine will not idle properly if it
is not present - (O-ring is often disintegrated). These parts are not shown in
service & parts listings as Yamaha did not want "emissions" related parts
accessed, however adjustments were often necessary to get New bikes to run
properly. Suggested setting position of the normally hidden mixture screw is
2 1/2 to 3 turns out from bottom.