10734 Kenney Street STE A -Santee, CA 92071 U.S.A - 619-258-6306 - Hours Tues-Fri 8am-5pm - *Closed Sat-Sun-Mon

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Thank you team Duncan! Couldn't be happier with the motor and the service provided by your team. It's nasty!!

Thanks again!

Chad Smith Honda TRX 250R

The quad runs better than we ever expected it to.  We are so pleased with with the build and your customer service.  DRI is truly one of the best decisions we have made.  We hope to have started a relationship that last many years and to represent your company on the box at every race.  We will keep you updated on our progress throughout the season. 


Matt Smallwood
Raptor 250

Want to thank you and your brother for all of your help and knowledge with my bike, all I can say is it's INCREDIBLE!

Thanks Again.
Donny Franks
Honda TRX450R
New York


Went to Ocotillo Sunday...You all did an amazing job..my banshee ran better than ever..once the break in was complete she was purring like I've never heard before..
Job well done Sir!

Thank you so much

Jason Schendel
'87 Yam Banshee


Hey guys, just wanted to say thank you for all the help you gave me with my son’s 450 trx. You guys went the extra mile with the e-mail’s and phone calls to make sure that I got it right! I went by the torque spec you gave me and no leaks! The Duncan team should be proud of the customer care and quality of work that they do for there customers. I am now a big fan of the Duncan Racing team, and I will spread the word about you guys. If I ever need any motor work or anything else, you guys are the first call on my list!

Thanks again. Jeff


"Dear Loren, I would like to thank you, Lenny and everybody at Duncan Racing for your care and continuous support. I am very happy with my Banshee and this build wouldn’t have been possible without your assistance and consulting in every step. While living on the other side of the globe (Cairo, Egypt) I have always found the prompt and timely assistance I need, not to mention priceless insight. I thank you once again for one bad #@# Banshee, and I am looking forward to the next decade of ATV madness.---

Regards, Sabala"
Cairo, Egypt

Both Bike Mods included:
Banshee National Midrange Kits, DR Bumper, Long travel suspension mods Roll/Elka
DR Quick change covers, Billet/DRI Mag covers, ITP Tires & DWT Wheels
Roll Footpads, Crown Brake lines
Roll Steering Stems w/Anti-Vibe mount kits
WORKS Connection Clutch Perch’s

Duncan Racing-
Just wanted to say thank you for the perfect job your crew did on my 2000 XR400R rebuild. I just got back from a 1,600 mile ride in Baja. I followed your recommendations for the break-in. The bike ran strong and without any issues whatsoever. Attached is a photo from the Sea of Cortez between San Felipe and Bahia de Los Angeles. Again...thanks for the build that left me with an ultra-reliable ride.
Carl McAllister


My lead mech pulled the studs out of the cylinder on a customer's LT250R - a new one that just had been ported at DR. He had installed them upside down...not enough thread engagement in the aluminum. Our repair didn't work out either. Loren, being the wizard he's proven to be thru the years, took the cylinder into his shop and FIXED it.
This customer uses this as a 1/10th mile asphalt dragger. It's standard bore with all PTR & DR parts and porting - the combination chosen by the team at DR. The ATV has become a passion to the customer. He's poured a ton of money in it. Past the engine, he's focused on custom titanium, carbon fiber, & ceramics...going so far as to even drill every bolt to make it as light as possible (1987 mdl...271# wet). It's not about bling with this guy.
Bottom line is that the combo works! It starts well, idle good, never overheats, and pulls like a Clydesdale. Everyone keeps trying to catch him. The money they've spent has so-far returned void of that result. There's undoubtedly someone faster out there. We just haven't found them yet.

Dave Short
Owner of Dave Superior ATV


Hi Leonard/Loren
In April I had picked up my Yamaha YZ450 quad from Duncan Racing. You guys did the motor and everything up for me. It worked great! I had no problems all summer racing. I thought I would send you guys a note to let you know how I did.
1st overall in Intermediate in the Albert MX Provincial ATV series,
2nd overall in ATV ProAm in Alberta MX Provincial series,
1st in the Western Canadian Amateur National finals in ATV Intermediate
1st in the Triple Crown Series (ATV).
Overall I won 9 – 1st place trophies and 2 – 2nd place trophies.
I would like to thank Duncan Racing and Leonard and Loren for everything you did.

-Dylan Yuhar
Whitecourt, Alberta

My experiences with Duncan Racing all started through recommendations to co-workers who previously either bought product or had engine modifications done to their own machines. My first purchase from DR was a chrome plated Paul Turner High Rev exhaust and Fat Boy silencer for my ’85 Honda ATC 250R. As soon as I opened my package I was blown away from the quality of the chrome and once installed the performance gain was equally impressive. This led me to ship them my ’96 Yamaha Banshee for a complete top end overhaul with their National Mid-Range engine kit. I had debated on what to get done for some time and after speaking with Loren Duncan over the phone and at the service counter I explained to him what I wanted in power. He went over everything that would be done in great detail and when it came time to pick my Banshee up from their shop I was given very explicit instructions on how to properly break in my machine and properly service it in the future.
During the break in of the ATV I could definitely feel the power increase of the engine kit and was anxious to feel the full potential of the engine. Once the break in was done, it was off to Pismo Beach to let the machine rip and have the best ride since buying the Banshee from the dealer. The power increase from the modifications met and far exceeded my expectations. From that point on I had no hesitation in recommending their work to friends and even future customers of mine as a parts counterperson at a Yamaha dealership. Beyond that I became an employee of DRI in parts and engine kit sales. Being able to sell parts and modifications that I believe in because I’ve had positive experiences myself was very easy and customers liked knowing this.
Through being a customer and employee I had the chance to get to know all of the employees of the company, which are mostly family members. Because the Duncan family name is associated to the company, I feel there is more of an effort on customer satisfaction and high quality products than you’ll find anywhere else. This is why I highly recommend the company to many people that I come across.

-Eli Madero

My experience with Duncan Racing all started when I purchased a used 86 TRX250R that only had a Paul Turner race pipe and silencer on it.  This was the first time I heard of Duncan Racing.  I contacted Duncan Racing to find out more about them and was mailed a catalog of their services.  I was interested in their engine kits and purchased the Eliminator High Rev kit.  I was very happy with the results I got with this engine kit.  Very reliable and never had a problem.  After 10 years with this flawless engine kit it was time for an upgrade when I learned about Duncan Racings PC2000 big bore engine kits.  I wanted another flawless engine kit and new I was looking in the right place for it.  I ended up purchasing the PC2000 305cc high rev kit.  Again very happy with the results.   The performace of the 305cc high rev kit is outstanding.  Pulls hard in all 6 gears no problem. Duncan Racing has an excellent tech support and is very helpful to get the best results.  When it comes to shipping Duncan Racing has always been accurate and on time.  I will always do business with Duncan Racing because they have proven me they are the best when it comes to performance and reliability.   -Scott Shine


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