Yamaha Raptor 250 DRI Team Graphics

Yamaha Raptor 250 DRI Team Graphics

89.95
With today's modern ATV 4-Stroke engines, making additional Horsepower is no easy task...This makes it critical that Engine Tuners have the Experience, Knowledge and Equipment to do the job properly.
Duncan Racing International's HP4 Valve Train Kit is designed to give you the utmost in performance and reliability by using the most advanced equipment and techniques in the industry. All porting work is performed by our master technician and valve seat cutting is done on our in-house SERDI valve grinding machine.

DRI HP4 PURCHASE OPTIONS

DR-275K $549.00 DRI Valve Train HP4 Kit without porting/valve seat machining Kit Includes: Camshaft Hardfaced on stock oem core(see cam profile options below), HD Valve Springs w/Titanium Retainers, Shortened Valve Guides, Big Valve Kit (+1.0mm S/S Intake)
Porting and SERDI valve seat cut Not Included
Kit must be installed by a trained professional
*Customer must send in stock cam core or pay core charge of $110.00

DR-275KP $995.00 DRI Valve Train HP4 Kit with DRI porting/SERDI valve seat machining Kit Includes: Camshaft Hardfaced on stock oem core (see cam profile options below), HD Valve Springs w/Titanium Retainers, Shortened Valve Guides, Big Valve Kit (+1.0mm S/S Intake), DRI Cylinder Head Porting , SERDI Valve Seat Machining and Professional Head Assembly w/Porting, SERDI Valve Seat Cut and Assembly*
DRI custom matches the intake manifold to the intake port on all Raptor 250 heads. Once this process is completed it is inadvisable to change intake manifolds. This custom service is included in the porting process all clients have to do is send in their intake manifold with their head or purchase a new manifold from DRI.
*Customer must send in head for modification or purchase new head from DRI.
** Customer must also send in stock cam core.
** *Customer must also send in stock intake manifold to be matched to Intake Port.

New Head Charge- $297.00
Cam Core charge-$110.00
Intake Manifold-$28.98

CAMSHAFT OPTIONS
Motocross Cam � Midrange Power (Lift: .368�/.368", Duration 270�/268�)

Baja/Cross Country- Bottom End Power (Cam, Lift: .353�/.353", Duration 262�/257�)

*DRI uses hardfaced cams built on stock cores.
**To insure highest quality, all camshafts used by DRI are made in the USA.

ADDITIONAL OPTIONS
Big Bore Kits and alternate compression ratio pistons are also available to use in conjunction with the HP4 Kit. Check the Big Bore Kit and Piston sections on our site for more info.

HP4 KIT FEATURES
In-House Cylinder Head Porting* (by Master Technician)
*Valve guides are removed during porting process to allow for greater port reconfiguration

Port Design Modifications Aided by In-House Flow Bench Testing and Computerized Port Mapping Software

Precision Valve Seat Machining and Reconfiguration*
*DRI uses in-house SERDI Valve Seat Cutting Machine used by F1, CART and NASCAR.

Big Valve Kits (Stainless Steel)

Heavy Duty Valve Spring Kits*
*With Titanium Retainers, Mandatory with High Performance Valve Trains

AMPCO 45 Shortened Valve Guides allow for usage of high lift camshafts. Port side of guides are modified to improve air/fuel flow through ports.

Camshafts of the Highest Quality Made in the USA

All Head Work Done In-House for Reasonable Turnaround Delivery Time.

Customers Can Send In Their Head for Modification or DRI Carries New OEM Heads in stock ready to build.

HORSEPOWER
HP4 Kits with porting offer gains up to 4 HP*.
*Results vary depending on camshaft profile and piston compression.

PIPE and IGNITION
For maximum performance, it is highly recommended to use a Fat Boy 4 Complete Exhaust and Vortex Ignition with all HP4 Kits.

HIGH COMPRESSION PISTONS and BIG BORE KITS
For maximum performance, it is highly recommended to upgrade piston kit with either a forged high compression piston kit or a big bore kit. DRI offers the folowing:

STANDARD BORE 250cc PISTON KITS
Piston Kit STD bore 10-1 Compression $225.00
Piston Kit STD bore 12-1 Compression $225.00
Piston Kit STD bore 13.5-1 Compression $225.00
*Cylinder hone recommended, pistons work in stock cylinders.

BIG BORE KITS
*stock cylinder MUST be modified to accomadate bige bore pistons. Cylinder must have nikasil plating stripped off, cylinder bored and cylinder replated and honed.
**Customers can send in their cylinder for modification or purchase new modified cylinder from DRI.

280cc Big Bore Kit 10-1 compression $575.00 (kit includes 280cc 10-1 Big Bore forged piston kit, Big Bore Headgasket, Cylinder Modification-customer send in cylinder)
Price with New cylinder $899.00 (customers send in nothing)
280cc Big Bore Kit 12-1 compression $575.00 (kit includes 280cc 12-1 Big Bore forged piston kit, Big Bore Headgasket, Cylinder Modification-customer send in cylinder)
Price with New cylinder $899.00 (customers send in nothing)

NOTE: 280cc is largest big bore piston that can be installed in stock cylinder core with using steel sleeve. Nikasil coated cylinders offer more performance and increased reliabilty over steel sleeves.

IMPORTANT NOTE When installing a high performance camshaft it is the responsibility of the engine assembler to check and confirm that the piston to valve clearance is adequate. Minimum clearance is .060" from valve to piston at peak lift. Tolerances can and will vary from engine to engine. There is not substitute for checking that these tolerances are correct. This is especially critical when mixing camshaft and pistons from different engine builders. One of the correct and easiest ways of checking this is by using the "claying the piston dome" method. Call DRI or consult a professional technician

Kits include Camshaft(s), HD Valve Springs, Shortened Valve Guides and Big Valve Kit.
Call us for Availability!
Add To Cart