DR.D YZ250F BUILD

 
(7/16/2012)
 
 Building the ultimate small-bore western racer
 
It’s not 1985 anymore. Back then, going off-road racing meant going big--it was all about size, horsepower and speed. But now, the bigger-is-better way of thinking is under attack. Yes, flying across the desert at mach one is easier on a big-bore motorcycle, but that opportunity really doesn’t happen very often in today’s racing. Western courses have become so rough and technical that you can make a good case for a 250F as the best real-world racer. That’s exactly what we have done here. Project Real World is based on a 2012 Yamaha YZ250F, which is a good bike in stock trim and has the potential to be a great off-road racer for the average guy.
THE BUILD
In years past, the YZ250F has been lacking in the horsepower department, but for 2012 Yamaha made some changes resulting in improved overall performance. To get to the next level we turned to the Yamaha experts at Dubach Racing Development (DRD), and longtime four-stroke hop-up shop, Pro-Tec. DRD and Pro-Tech came up with an engine package using an LAPC piston with the stock crank, cams and valves. The head was only cleaned up slightly. We also installed a DRD wet sump kit, a complete Hinson Racing clutch and a JD jetting kit. Our real world racer would run solely on good, old pump gas, which makes our pocketbook smile. Then we turned to Mishi Moto to keep it cool, with oversized crossed braced radiators including high pressure cap and a very trick looking set of hoses, heat would not be an issue for this powerplant.
With engine dialed we move to the handling department. The 2012 YZ250F has a tendency to seem a little busy, unlike the stable planted feel of years past. Factory Connection took on the challenge of getting this feel back. Applied Triple Clamp set up with a Scotts Stabilizer on top will help with all those unexpected hits.
IMS handled our need for greater fuel capacity with a 2.5 gallon tank. You can order the tank with a normal filler or a an opening for a Dry Break filler. We went with a normal filler that accepts the stock cap.
Any serious off-road race bike needs certain bases covered. Protection is at the top of the list. We used Enduro Engineering’s pivoting hand guards and a skid plate that includes wrap around engine guards. TM Design Works chain slider, roller, and rear guide kits are on many of today’s top off-road racers machines. The stock YZ250F comes with a 19”inch rear wheel, we prefer 18”inch and this helps with added protection from flatting. DNA offers a great looking set of wheels at a decent price; we wrapped them with Dunlop rubber; MX51 in the front and a 952 for extended life in the rear. Helping get power to the rear tire, Dubya sent us a set of Tallon sprocket and EBC took the duties of stopping the machine, providing a huge 280mm oversized front rotor kit using Xtreme Pro pads.
THE RESULTS
 The engine has great response off bottom, a noticeable improvement over stock in the mid-range pull and seems to rev longer on top-end. The DRD and Pro-Tec mods didn’t change the power characteristics of ourYZ250F, just gave more all around, which makes it easy to ride.
Factory Connection gave a very predictable, plush feel a little on the soft side for normal sized test riders. With suspension, engine mods and a plethora of bolt-on goodies we came out with a great all around race ready small bore machine.
We think we proved our point. The Real World Racer is a great bike for desert and it still works as good as ever on a motocross track. For racing, it’s probably the ultimate machine for the District 37, which has a class especially for lightweight four-strokes. The vet divisions are also broken up into engine size. But even if they weren’t, the YZ is still a winner. On half the courses we ride it’s just as fast as a 450.
And its more fun on all of them.
 

CONTACTS
DRD Hour meter  $64.95  www.dubachracing.com
DRD Radiator Lowering Kit $119.95  www.dubachracing.com
DRD Wet Sump Kit $179.99  www.dubachracing.com
DRD Brake Line Mount $29.99  www.dubachracing.com
DRD Complete SS/AL system $579.95  www.dubachracing.com
Pro-Tec4 Stroke Head Mods-Machine, port, flow $530.00  www.protecpeformance.com
Pro-Tec Airboot With Mods $65.00  www.protecpeformance.com
Valve Spring Kit $129.95  www.protecpeformance.com
Pro-Tec Jetting Kit $62.00  www.protecpeformance.com
Factory Connection fork & Shock revalve $180.00 each www.factoryconnection.com
Decal Works custom made graphics $199.00  www.decalmx.com
Polisport Complete Plastic set $129.00  www.decalmx.com
Front wheel Red/Blk DNA $630.00  www.dnamxwheels.com
Rear wheel Red/BLK DNA $780.00  www.dnamxwheels.com
Rear sprocket Tallon $64.99  www.dubyausa.com
Front Sprocket Tallon $25.99  www.dubyausa.com
Pro Taper Conture Bars $74.99  www.protaper.com
Pro Taper Chain Gold $84.95  www.protaper.com
EBC Oversize Front Rotor Kit  $299.99  www.ebcrotors.com
Applied Racing BLK Clamp set stabilizer ready $480.95  www.appliedrace.com
Dunlop 952 rear tire tk www.dunlopmotorcycles.com
Dunlop MX 51 front tire tk www.dunlopmotorcycles.com
IMS Oversized Tank $274.95  www.imsproducts.com
Scott Stabilizer with Mounting kit tk  www.scottperformance.com
Torc 1 Rear Brake Pedal  tk  www.torc1racing.com
Torc 1 Shift Lever  tk www.torc1racing.com
Zip Ty Chain Adjuster Blocks $34.99  www.ziptyracing.com
Filter Skins  tk www.pcracingusa.com
Flo Air Filter  tk www.pcracingusa.com
ODI White Soft Grips $9.95  www.odigrips.com
Hinson Complete Clutch Kit/Cover $1,054.99  www.hinsonracing.com
Assorted Maxima N/A www.maximausa.com

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WARNING: Much of the action depict­ed in this magazine is potentially dan­gerous. Virtually all of the riders seen in our photos are experienced ex­perts or professionals. Do not at­tempt to duplicate any stunts that are be­yond your own capabilities. Always wear the appropriate safety gear.

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