DRI has spent 1000's of hours doing R&D on 2-stroke Engines/Cylinders/Port types designs to MAXIMIZE PERFORMANCE and RELIABILITY . There are no quick read manuals to explain the complexity of 2-Stroke porting.
Data must be gathered-recorded and analyzed, to help properly design cylinders that not only perform properly but give the reliability and consistency expected from DR/PTR Cylinder.

• DRI has proven port designs for ALL Applications; Desert, MX, XC, Off-Road, Sand Dunes and Sand Drags, Ice Racing, Enduros, Serious Trail Riding, etc. You name it DR has built cylinders that have raced it.

• DRIs have won more Pro ATV Races and Pro ATV Championships than any other company in the world over the last 4 decades. DRI has spent 100's of hours doing R&D on 2-stroke port cylinder port designs

• All port work is 100% Guaranteed

• All PTR cylinders have port timing degreed in and all port dimensions are blued and scribed for MAXIMUM consistency

• PTR Porting is a labor service modification

• All PTR porting is performed in house. By Loren Duncan

• All PTR ported cylinders and individually serial numbered. With data recorded in a DRI data file, for future reference

• For Maximum performance and reliability with a PTR ported cylinder it is imperative the piston, rings and cylinder bore are kept good conditions.
  Piston clearance should ALWAYS be kept under .005 of an inch * Contact DRI for more details

• Quality Cylinder Boring and Proper Port Chamfering is critical to the performance and reliability of your cylinder.
  When these services are required for your engine, be sure that they are performed by DRI or a highly trained technician

• Call DRI for one on one consultation about your machine, riding and your needs. #619.258.6306

• Paul Turner Racing Products are a proprietary brand of Duncan Racing International, Inc.

Yamaha Banshee Porting Type Options

NATIONAL Cross Country (low end)

NATIONAL Midrange (midrange)

NATIONAL High Rev (top end)

All PTR porting types same price.
PTR Porting and Stock Head Rechambering $895.00

PTR Porting (use Billet Powerhead at additional cost) $750.00
Powerhead $349.00
*If customer already has a Powerhead, they may purchase a matched dome(for ported cylinder)for $69.95 and use their existing Powerhead outer shell.

*Cylinder Boring and Pistons are not included in price. DRI can bore cylinders and supply new piston at additional cost

Models
Fits:
Yamaha Banshee (all years)

Cores Required
Cylinders and Head (if stock head modification is desired)
*Customer must send in their cylinder for PTR Port modification or purchase new cylinders direct from DRI

Power Emphasis
NATIONAL XC :Power emphasis very Strong Bottom and Good Midrange Pull
Best Carburetor:34mm PJ Keihin
Best PTR Pipe: Midrange

NATIONAL Midrange: Good low end throttle response, excellent midrange, good top end,
likes to pull a taller gear
Best Carburetor:34mm PJ Keihin or 35mm PWK Keihin
Best PTR Pipe: Midrange or High Rev

NATIONAL High Rev: Power emphasis; good Bottom end Strong Midrange Pull, Very Good Top End.
Strongest Power at 3/4 throttle
Best Carburetor:35mm PWK Keihin
Best PTR Pipe: High Rev
DR also offers custom porting for stroker engines. DR will degree in port specs to your stroker crankshaft.
DR can also perform custom head mods and custom dome rechambering

Power Gain
Over 20% over stock, peak

Reliability Rating
With proper maintenance, PTR Porting is 80% reliable as stock

Application Recommendation
XC/Low End: Cross Country/Tight Woods Riding and or Racing

Midrange: Motocross, Sand Dune Riding, Trail Riding, Gran Prix Races,
*Best Overall PowerBand

High Rev/Top End: Drag Racing, Hill Racing, Asphalt Drags, TT & Flat Tracks


Special Notes

All port work is 100% guaranteed

All PTR cylinders have port timing degreed in and all port dimensions are blued and scribed for MAXIMUM consistency

PTR Porting is a labor service modification

All PTR porting is performed in house

All PTR ported cylinders and individually serial numbered. With data recorded in a DRI data file, for future reference

For Maximum performance and reliability with a PTR ported cylinder it is imperative the piston, rings and cylinder bore are kept good conditions.
Piston clearance should ALWAYS be kept under .005 of an inch

Quality Cylinder Boring and Proper Port Chamfering is critical to the performance and reliability of your cylinder.
When these services are required for your engine, be sure that they are performed by DRI or a highly trained technician

Paul Turner Racing Products are a proprietary brand of Duncan Racing International, Inc.

No company in the industry can match DRI's record for 2-stroke ported cylinders. PTR Banshee cylinders have set the standard for both racing and recreational usage