T4 Carb Tech
KEIHIN  PWK 39mm

A popular Carb upgrade for the T4 

Stock 1987 T4 Carb - Mikuni 34mm Round Slide

Stock 1988 T4 Carb - Keihin 35mm D Slide

POPULAR REPLACEMENTS

Great MX, Woods, Dunes Carb - probably most popular Carb upgrade?

Easy to get replacement, Factory 2 stroke 250cc dirt bike carb - late 90's on up.

Great Race/ Dune Carb - no Jets, Improved Fuel economy, easy adjustments.  Big Bores 40mm+ 
Mikuni TM 38mm Flat Slide
Idle to 1/4 Throttle
Pilot Jet & Pilot Air Screw

* Pilot Screw turned in - Reduces Air/ (Richens Gas)

* Pilot Screw Turned out - Increases Air/ (leans Gas)

* If more that 2 turns out = use next smaller Pilot Jet

Jet Needle

* Tapered  needle  atached to slide

* Thinner = more midrange fuel

* Thicker = Less midrange fuel

* Held onto slide with Clip & Adjustment grooves

* Higher Groove  (needle sits lower in the vetury tube)Leaner midrange

1/4 to 3/4 Throttle
3/4 to Full Throttle
Main Jet

* Jet Needle is totaly up - ventury tube fully exposed

* Different size Jet Holes - bigger hole = more fuel

* Number on Jet - Bigger number more fuel