Hey Dan, Thanks for the map for the RS 548 in our 135SE it was an easy download, and the bike runs great. Amazing torque and the lope at idle sounds like a bike that would be fun to ride. Great work and product!!! Dave

Hi Zipper's!!

Just wanted to thank you guys on my 124 kit I purchased couple years ago, finally took it to the track for some runs. I took on everything from 117 cvos to 135s smoked em all!! And I’m running a 48 Mukuni last race was with a metric bike and he only had my by a bike length!! Thanks again!!!

SV

AMAZING results with the #517-986 Sport-Tour 128 Kit on my 2021 Roadglide 117. . . . I considered the 128 Muscle kit but chose the Sport Touring with 6 less HP but 4 more ft.lbs. torque. This engine is as tame as a factory stock engine when riding gently, but an absolute beast when I open it up. The torque comes on strong at low RPM and never lets up, and the fuel economy is over 40 MPG when I ride it sensibly. I’ve owned dozens of custom engine builds in 50+ years and never had such a perfect balance between rideability and performance. Anyone can build an engine that shows big numbers on a dyno sheet but is worthless in the RPM ranges we use every day. There’s no question these Zippers kits are the best in the industry.

"A big thanks to you fellas for directing me to Top Dead Center Performance in Rosenberg, Tx. Working with Rossana and Josh was AWESOME! Rosanna, really knows her stuff and Josh killed it on all the install and dyno work. They turned my timid girl in to a BEAST. the RED SHIFT 468 upgrade delivered as promised. Thanks again to Zippers tech and customer service guys for all the guidance, info and advice. If you're on the fence about performance upgrades, look no further...this is the place."

"Just want to thank you again for all your help with my build. And for putting up with me.  Joe at M&S did a great job. I picked it up Friday at 4pm and took it back 900 break in miles and changed the oil. Took her out and hit hard and this thing is amazing. Exactly what I was looking for. Took her up into the mountains runs unbelievably well!"

"It was so helpful helping me do this cvo 103 build hard matching up parts. Zippers are awesome. The bike goes unreal took a 110 screamin eagle camed up so very happy. You wont go wrong dealing with zippers." Thanks Bill W.

"I have been a customer of Zipper's since the 90's. They back cut my transmission gears to shift like a dream. We installed a Zipper's S&S Super 'D' Carburetor with 3 Thunder-Jets. In 1997 my stock 80 cubic inch Harley registered 120 horsepower to the rear wheel in open competition at the AMI Brute Horsepower Shootout in Daytona Beach during Bike Week to win First Place. I have called on Zipper's for performance advice and parts many times. I have both faith and confidence in Zipper's Performance." Respectfully, Dyno#1

"I have done multiple performance upgrades from intake to exhaust and parts in between, but this cam, Red Shift 468,  was the single-most awesome performance upgrade I have ever made. Some upgrades are just noticeable on the dyno numbers, but this upgrade is beyond noticeable as a rider in the seat. If you are thinking about an investment to increase performance, I would pull the trigger on this one today!"

"Had issues with using a belt drive system. Decided to use a chain. I called Zippers and spoke with Pete Stewart. He helped me work through my ignorance and get it right. I now have a completed project with a Zippers chain kit! Thanks Pete for your great customer service." 😎 Mike in Alaska

"Just had Ricky's Custom Cycles install a 103 Muscle kit in my stock 96 cu Street Glide & man what a real kick in the pants now. Put the 103 Muscle kit, Stage III ported heads, S/S crank/rod combo, & a D&D Big Mouth Exhaust System. Holy Smokes is this bike FUN now! With the Thundermax tune along with these Dyno matched components, my scooter is Bad Ass Now. Love the sound at idle & going thru the gears. Two Thumbs Up to Zippers for a well thought out kit & to Ricky Stewart on a First Class Job! I recommend upgrading the clutch assembly to an after market like the Bandit Sportsman to complement the all new performance. You will not be disappointed." Billy "EVO" Schuh

"I am an avid SPORTSMAN performance enthusiast . Just wanted to say I purchased a Zippers Muscle 128 kit and so far have logged 8k miles on the motor. The engine runs great and I have to say the way is designed its truly one the best kit I've purchased! Looking forward to my next project with Zipper's." EC Florida Zipper's Muscle 128" Kit for 2017-2019 114 & 117" Milwaukee-Eight® Models https://www.zippersperformance.com/zippers-muscle-128-kit-for-2017-2019-114-117-milwaukee-eight-models/    

"Zipper's Performance is selling more than just the "next best thing". Instead, they focus on the customer's goals and work to provide the very best, most comprehensive performance solution. Additionally, I know the staff at Zipper's Performance is dedicated to my business because they know me. When I call in, I recognize the individual employees (most of who have been there for many years) and they know me. They support my growth efforts and help me use the resources Zipper's has available to expand."

"I wanted to check in after riding the bike for a couple hundred miles. Took it to the beach last weekend. Now I know that there was in fact something missing with the bike. It just simply feels better, tighter. (because something was loose inside the motor) It is more fun to ride now.

Again thank you guys for taking it in and turning it around in 1 day. As you told me, you guys had an idea of what the problem might be, and were right. Had I listened to all the roadside mechanics, I would have been spending money on parts that were not bad.

I will be letting anyone who asks about getting their bikes fixed to give Zipper's a call before going anywhere else."

"I acquired this bike from a friend who was quitting riding. After riding it I decided it was boring. With only 40hp is was really not that fun to ride. You had to wring the hell out of it to have any fun and it felt like it did not like that and was overstressed. I had Zippers do their magic. They installed the 1200cc Torkster kit. WOW. What an improvement. It is like a different bike. It is much smoother, power is everywhere. It does not matter if you are at 2000 rpm or 4000rpm it pull like a freight train. Not scary fast like a hot rod, not peaky or temperamental, just clean power everywhere. It double the HP and TQ over stock with no negative side effects. I have had faster bike, but none ran an smooth clean or were as enjoyable to just go out and ride."

"My wife and I are in Meadows of Dan - MP 174.2 of the Blue Ridge Parkway. We have ridden about 650 miles so far - likely another 650 before we get home. You guys are the best. The new TMax on my wife's Fat Boy is working perfectly. Thanks for the adjustments. The performance upgrade on the Ultra Glide is outstanding - I don't mind downshifting, but I could get away without it. I love the kick I get any time I apply the throttle. Digging thru the Parkway at 45 to 50 in 4th is an absolute blast. Getting up to 60 takes about a second. If you know Luray, VA, you know when coming out of town there is a steep hill on 211 as you leave Uncle Buck's Restaurant. I inadvertently started off in 2nd - and just ate that hill up. Thanks everyone - you are a great team. Thanks Bob - you are a genius with your toolbox."

"Just a line to thank you guys after purchasing your G2 Carb - I have been fighting a carb that had a ThunderJet and other things done to it. I even tried to straighten it out [by] jetting it, etc. Then I decided to buy a new G2 Zipper's Carb. WOW, seriously, this was the best investment to my bike with a (S&S) crate motor that I could have done. Right away the bike settled down - idle, cruising, and especially [at] the drag strip. It gained 4 tenths and 6mph the first 2 passes down the track. After slightly rejetting, I gained another 10th the next weekend [at] State Capitol Raceway, Baton Rouge, Louisiana. So thank you again for a great product!!"

"Waiting for Harley to do something good, finally I bought a 2014 Ultra Limited. Love the changes and handling but unsatisfied with the drive train. Based on past experience with the Zipper's Service, Support, and Products I decided to run the combination of a High Flow Air Kit, the ThunderMax, and a set of RCXHaust. Simple – Clean, woke the 103 right up. Before, the response was very unstable – issues with throttle response below 2000 RPM and always felt restricted on WOT. After – very responsive at any PRM, the 'Beach' (sand beige and brown) pulls hard thru top end. Thanks to Dan and his crew. Thru the years of HDRA racing and upgrading client rides they have continued to provide top notch product and service. And, for the few issues with tweaking the TMAX to a clients' bike, the TMAX Support team has been right on top of analyzing captured data and providing recommended processes."

 "My son found this 2002 Ultra Classic for me on Craigslist... cheap. It needed repainting which will be done soon. Otherwise he was told by the original owner, who was a retired Certified HD mechanic… who did all his own work on this bike… that it was a 95 inch motor with a .510 S&S cam, etc. Long story short the seller was the fourth owner. He was never an HD mechanic and did not actually know what was in the bike.

While installing new cam chain tensioners, my mechanic discovered it has an Andrews cam similar to a .510, which he thought would have been bigger for a 95 inch. After new brakes, rotors, tires, tensioners and installation of the ThunderMax, there's still a lot we don't know about this bike. However, what we do know is this thing runs like a batt. Gobs of torque, very smooth... no pings or hiccups, great mileage, etc. We still don't know what's in this bike, but the ThunderMax does and that's all that matters. Great product. Well worth the money. HAPPY, HAPPY, HAPPY"

 “First, I know we are in an enthusiast-based business where clients want to spend hard earned money, but they want to spend it wisely. Only a small number of motorcycle shops acknowledge this. It is important to me to build strong relationships with my clients. I want to give my customers the best choice the first time, rather than just collecting cash. As a small shop owner, I work with the same clients or the same motorcycles all the time. I've been in business for over 30 years, and I've worked hard to earn my customer's trust and repeat business. I want to deliver a top of the line product that keeps them coming back.

Zipper's Performance Products shares the same philosophy. I know my business is important to them. Not only do I receive excellent sales service when dealing with Zipper's Performance, but I also receive personalized tech support. The staff at Zipper's is extremely knowledgeable and will go out of their way to help me, 24/7. Zipper's Performance is selling more than just the “next best thing”. Instead, they focus on the customer's goals and work to provide the very best, most comprehensive performance solution. Additionally, I know the staff at Zipper's Performance is dedicated to my business because they know me. When I call in, I recognize the individual employees (most of who have been there for many years) and they know me. They support my growth efforts and help me use the resources Zipper's has available to expand.

As a business owner, I know I am partnered with a successful, national company who treats my business uniquely and not as another account number. Zipper's Performance provides me with quite a few sales leads and, as far as I'm concerned, is here to stay in my shop. Important resources like tech support and training are always available (just ask!), with 24/7 sales support available by phone or email, and I am treated with the same one-on-one focus I give my customers. Even though I am a fairly small shop, I am here to stay and Zipper's values my business.“

 “I LOVE my ThunderMax TBW system. I have had it for 3-4 years and haven't touched it since the original install. I have recommended it to many people and the ones who have purchased ThunderMax's are delighted with the results. I keep close watch on my gauges, feel, and fuel mileage. I ride 1 and 2 up on short and long hauls. Usually, I am running above 45mpg and on the last, long haul through the mountains and roads from NJ to upper Vermont, I range between 47-50 mpg. Engine temps are a lot cooler now than before, too. Thank you for the super product!”

 “I have a 2010 FLHX what I've modified quite a bit. 106” S&S Big Bore Kit, Ported Heads, Welded & Trued S&S Flywheel, Fueling Oil Pump and Cam Plate, Free Flowing Air Cleaner, V&H Pro Pipes (2-into-1), several drivetrain upgrades, Red Shift 575 cams, and a ThunderMax ECM. I purchased Red Shift 575 cams to focus on torque, and it certainly has torque! The front wheel likes to get airborne, especially when riding 2-up. I've tweaked the tune to where I feel like I'm not leaving much on the table. My highway riding is great. I can roll on in 6th gear doing 95mph and still pull, but not for long. I can push it to 5k in 3rd, 4th, and 5th, and get up to 120ish in 6th. I'm an aggressive rider and I push my bike hard when I'm having fun. Most of my riding, though, is done at sane speeds within sight of the speed limit. Thanks for some great products!”

 “Hello! I purchased a ThunderMax with AutoTune, Red Shift 575 cams, upgraded bearings, Fueling lifters, upgraded oil pump, plate, Red Shift Chain Tensioners, and Rinehart true duals. These are all great products and my bike runs great! Thanks!”

 “I would like to thank all of you for how pleased I am with my bike! I put your Thunder Sport III Heads and the ThunderMax with AutoTune on my 2006 Night Train. The performance is like night and day! I'm very happy with your products. Thanks so much. The power band is great and the throttle response is spot on. It runs pretty hard! Thanks again!”

 “I just got finished installing Red Shift 575 cams from Zipper's Performance in mine and my brother's bikes. I, also, installed all of the peripheral parts: inner bearings, chains, sprockets, Red Shift tensioners, Baisley oil relief plunger, Fueling lifters, adjustable pushrods, and new gaskets. We are both very pleased with the performance gains!

If you want to put a smile on your face with a distinct kick in the butt sensation when twisting the throttle, I highly recommend this cam. I installed these parts in two bikes: 2010 Fat Boy and 2011 Blackline. I, also, had previously installed the ThunderMax with AutoTune EFI controller, free flowing air cleaner, and D&D Fat Cat 2-1 pipes for optimum performance.”

 “We are so pleased with our purchase. The ThunderMax system is fabulous! Zipper's Performance was such a great help and were there to answer any of our questions. What a difference this has made to our ride!!! We cannot recommend this enough to others. It was well worth the cost and the change in power is immediate. What a great product! Zipper's Performance was there for us from start to finish! We will be coming back for more items in the future. Thanks for all of your assistance.”

 “I just wanted to let you guys know that the ThunderMax install with Red Shift 525 cams, 2-1 exhaust pipe, and MAXFlow air cleaner is awesome! Big difference! My bike starts easier when hot, runs much smoother, and has a boat load of torque from just above idle and up. Another great job from the folks at Zipper's Performance!”

 “I purchased a ThunderMax from Zipper's Performance last fall when the cold front was sneaking in. I ordered the ThunderMax, HiFlow air cleaner, and Rinehart pipes. There is a remarkable difference in power, and I noticed it right away. I could cruise in five gear around 40-45 mph and the bike doesn't jerk like it used to! Everything is running super!”

 “I have a 2013 Street Glide I purchased in October. I have done many modifications to it since then as you can see in my pictures. I was looking at cams to give the stock motor a kick in the butt. I have a local guy to me in Harrisburg, PA that came very highly recommended from friends that have engine work done with him. I went to him several times asking questions and what he recommended. He talked to me about the Zipper's Red Shift 575 cam for my bike. I told him I would get back to him on what I wanted to do.

I read a lot of the forums and I read a lot about other brands of cams. I went back and asked him about those brands. His response to me was “Do you want it to run good on a dyno or good when you're on it?” I don't care about the numbers - I want it to run good when I'm on it. My mechanic has been in the business for a long time and I trust his opinion. He's the expert, not me! I went with the Zipper's Red Shift 575 cam and the Red Shift tensioners. WOW, it is like a new bike! I am so happy with the cams, they WOW me every time I ride. They awesome, awesome, awesome!”

 “I have the ThunderMax installed on my bike and I'm a happy customer! I have had it for about 3 years and never had to do anything except ride.”

 “I just wanted to say ‘You guys rock!' Zipper's Performance did some headwork for a buddy of mine and they rip! I'm saving up now so I can purchase the same ones.”

I have a 106 build with Red Shift® 575 cams. I love them! Great hp and tq! I will always use Zipper's products now. Power - 114hp 118 tq!

I would like to take this opportunity to express my complete satisfaction with the ThunderMax® Electronic Control Module (ECM) and Red Shift ® 575 cams. My 2009 Street Glide® is an excellent motorcycle. However, while it had a decent amount of torque it was somewhat lacking in horsepower. This became more pronounced when I was riding with baggage for a weekend (or longer) trip and a passenger. I had to insure I had my RPMs up when I was accelerating from a stop, and I had to give myself sufficient room to pass someone on a two-lane highway. So I had Zipper’s install a MAXFlow Air Cleaner, 4” D&D back-cut slip-on mufflers, Red Shift® 575 cams, a ThunderMax® ECM (with Auto Tune), and 106” cylinders.

The difference is night and day! I haven’t put the bike on a dyno yet, but the increase in both horsepower and torque is off the charts! I picked the Red Shift® 575 cams because they deliver lower RPM power. The Street Glide® is a heavy bike and wouldn’t benefit overly much from a higher horsepower/lower torque set up. The end result is I have a staggering amount of power between 2000 and 4000 RPM, where I do most of my riding. No longer do I have to worry about increasing my RPMs off the line with a heavy load, and I certainly don’t have to worry about giving myself an inordinate amount of time to pass someone on a two-lane highway. But the true joy of this combination of Red Shift® Cams, ThunderMax® Auto Tune ECM, and larger cylinders is felt on the twistees,” the wonderful back roads all motorcyclists love to ride. I don’t have to downshift as much as I used to have to do since I have so much power as low as 2,000 RPMs. And I have an incredible amount of power to come out of the turns with or to climb the steep parts of the road. And the amount of sheer, raw power when cruising at highway speeds is positively intoxicating. I have and have had very fast motorcycles in my life. In 1971 I bought a Norton® 750 Commando in London. I owned a 1999 Sportster® Sport that I modified with cams and a Supertrapp® exhaust. And I currently also own a 2002 Wide Glide® which has been dynoed at 106 horsepower and 111 foot pounds of torque. And my Street Glide® walks proudly in that heritage with the newfound USABLE power that I’ve gotten from the Red Shift® 575 cams, ThunderMax® Auto Tune ECM, and 106” cylinders. I plan to ride to Sturgis, SD this summer with my wife and then cruise the Black Hills. Now I am REALLY looking forward to the ride. My Street Glide® can handle anything now.”

I purchased my ThunderMax with Auto Tune for my 2012 Street Glide and it is awesome! My bike is completely different. Burn outs are more intense and no matter what fuel I use or elevation I'm at bike automatically tunes for best performance. The guys at Zipper’s Performance were very helpful with sales and technical support. I couldn't be happier!”

Wow, what a difference! I don’t even know how to describe it… Riding on 97 used to be a pain - cars zipping by me - but today, it felt as though I had tons of reserve power regardless of how fast I was going or what gear I was in. Even going uphill was so incredibly smooth! I didn’t have to increase speed to move to the fast lane – the power was just there when I needed it.

I remember when I had the other tuning device and my pipes installed, the only thing different was the volume, not a big difference in power, but today was awesome!!! No wonder you guys get such incredible reviews… Zipper’s Performance and ThunderMax® ROCKS!

Installed 3 ThunderMax's® today. Every customer is happy. Love your products!

I just installed Zipper's Red Shift® Cam Chain Tensioners, Red Shift® 525 cams, inner bearings and Fueling® lifters. I remapped my ThunderMax® and my Trixie runs great! Great products guys!

If you want your Harley® to haul ass, give Zipper's Performance a look see for go fast goodies!

Thank you, again, for the prompt attention to my request for information concerning your product. The tech that assisted me was helpful, courteous, respectful, resourceful, and genuinely believed in the product he sold. Way to go! I know I will be spending my dollars here and at the same time recommending this company to others.

The ThunderMax® is soooo much better than other popular tuning products! I, personally, will only ride with a ThunderMax®. Even my friends say it's an improvement over the other device I had installed from the instant I started the bike. I would recommend this, and do, to anyone!

I had another performance tuner and exhaust before, and getting rid of them and putting in the ThunderMax® with AutoTune has been the best money I have ever spent on this bike! I am so grateful for this improvement, you cannot imagine. I am looking forward to one of the best riding seasons since I have owned this bike. Thanks again for the ThunderMax® and for your great support!

I just wanted to thank you for all of your help with my customer's Trike. The customer picked up last week and rode it home, then called me to express how happy he was. The map that Zipper's did was perfect and we appreciate all of your hard work. We will continue to use and recommend using Zipper's products!

The Chain Conversion Kit from Zipper's Performance is very good and easy to install, too! My bike rides the same, with lower rpms and higher MPH now. I still get rubber in first three gears, power is not affected at all either. I'll be doing more business with you guys!

I had the ThunderMax® EFI on my 2011 Road King® Classic. It worked very well with my high flow air cleaner and performance true dual exhaust system. I sold the bike when I deployed to Afghanistan. Now that I am back, I will install another ThunderMax® system on my 2013 Ultra Classic® Limited. Can't wait until the weather turns better!

I rarely find the motivation or have the time to write and express my gratitude in regard to purchases I make or service I receive. However, in dealing with Zipper's Performance I feel more than compelled to do so. From my first contact with Jeff Curlis in establishing my purchase, to working with Rob Jordan to bring my installation to a successful completion, was one of the best if not THE best purchasing experience I have ever had (approaching the purchase of my bike - and that says a lot). Jeff not only provided me with my ThunderMax® unit and D&D® Bobcat exhaust, he went out of his way to make sure I received my parts in order to accommodate a very small timeframe window I had to perform the installation. Although I am mechanical, I have never done anything with an ECM. As such, I found myself somewhat out of my depth during the installation. I reached out and Rob Jordan was there consistently keeping me on the correct path. Anyone who has waded into unknown maintenance territory (when they'd rather be out riding) knows the value of this kind of assistance. In the end, the ThunderMax® ECM and D&D® Bobcat exhaust have transformed my bike. It's a beast! Heads turn as I go by and I get compliments just about everywhere I go. Every gearhead I talk to I always talk up Zipper's and the ThunderMax®. I am a big fan!

We just ordered our 14th ThunderMax® at my shop. I do all of the programming. We love the ECMs and the programs are easy to use and reset the values. Thanks for putting out such an awesome system.

Just finished a 2012 Road King® Stage 1 upgrade with ThunderMax® TBW, Zipper's MaxFlow A/C Kit, and Rush® 2 into 1 Black Ceramic exhaust. My bike sounds great with good low and mid-range torque, and not to loud at highways speeds. She breaths way better now.

Thank you so much! Amazing customer service, fantastic support and the reputation that goes with Zipper’s products! I have to admit my friends get tired of hearing about how great this company and your products are!

I placed my order with Zipper's Performance. It was a pleasure dealing with the sales rep there. I love your product! I bought the Zip Kit for my 2007 Ultra Classic®. Thank you very much!

I purchased a ThunderMax® with AutoTune ECM from Zipper's Performance for my Harley-Davidson® 2011 Street Glide®. It did just what you advertised it would do, especially with the cams, air cleaner and exhaust system that I also added. It really gets up and goes!

It was late in the fall after I installed the ThunderMax® with AutoTune in my 2007 Fat Boy®. I had only had a short ride after the installation, but I was completely satisfied with the results. Installation was very easy. Money well spent! Thank you for the outstanding product!

I am really happy with my ThunderMax®. I fitted it to my home made turbo 96 cube Fat Boy®. The bike makes 130 HP and 147 foot pounds of torque. The bike rides like a stock turbo - no flat spots or fuel surge. I get really good fuel economy, too. The best thing is I can tune at home. ThunderMax® got my vote! I sent a picture of drag day... We just ran all day long and never missed a beat!

I have a ThunderMax® on my very modified 107 C.I. Road King®. I am totally happy with your product. Being a business owner also, you are very lucky to have the very talented personnel. GREAT PRODUCT! GREAT TECHNICIANS! GREAT PEOPLE!

I have a very challenging bike to tune - a high compression 107. I bought the ThunderMax® because my stock ECM had an unfortunate accident. The bike had been tuned by a very competent tuner. The ThunderMax® is hands down better - way better! I like the fact that I can upgrade any time. NOS may be in the very near future.

I installed ThunderMax® on a mostly stock Sportster® (except for pipes and air cleaner). Instant difference! More power and acceleration! Excellent drivabilty throughout all rpms! ThunderMax® is the best mod I could have done. I love the user adjustability. It's easy to use even though I am not a tuner or engine builder. The adjustable rev limit, rpm logs, and head temp logs are nice features. Nitrous and boost compatible is a huge plus for me! I thought it couldn't get better, but then I installed the Zipper's Super Hammer Kit... Amazing! Easy to install - tons of power - good drivability - raises power band a good bit, too! The bike is still easily streetable. Zipper's set me up with everything I needed to get going.

My bike runs like a TOP! COMPLETELY SATISFIED! (True Duals, Red Shift® Cams, High Flow Air Cleaner Kit).”

I just wanted to let you know how pleased I am with the work that was done on my bike. The pipes that were installed look great and the performance from the ThunderMax® is awesome. Again, I am very pleased with the fantastic job. Please let everybody know how pleased I am. Thank you!”

Concerning your Magnum engine, it blew our expectations! It is an absolute beast and great care must be taken when twisting the throttle. Our customer is more than happy but I believe he is way overpowered. The bike only weighs 196 kg, so you can imagine how eager the front wheel is to take off. Nonetheless, I will contact you soon for our client wants another engine of yours.”

LOVE my ThunderMax®! It kicks ass!”

Thank you for the ThunderMax® TBW w/ AutoTune install at Delmarva Bike Week. Nice install job and the bike is a whole different animal now. Really runs great!”

Wow! What a difference on my 2011 FLHT®! Thanks go out to your staff at Delmarva Bike Week on the install of the ThunderMax® and Rinehart® exhaust on my bike. Very professional! Thanks!”

ThunderMax® is the best thing I did to my ’09 Ultra!”

My FLHX runs stronger and gets better mileage than OEM or other popular brand ECM equipped bikes I ride with. They have also spent far more $$ on engine work and Dyno tuning. Love my ThunderMax® and Red Shift® 575 combination!”

I have been riding with this on my Softail®, and I have nothing but extreme satisfaction to report…. Amazing product! My baby runs soooo smooth… Softail® owners, get yours! Best investment to date!”

Best money I ever spent… It woke up my 103” Heritage Softail® perfectly!”

I took my first run with my new D&D pipe and ThunderMax® with Auto Tune system installed. All I can say is, damn! I can literally feel the bike running better with every run and some other problems have been corrected too: Better starting, no lug with a low rpm take off, etc.

The ThunderMax® is a great product and you’ll find Zipper’s Performance is a great company to do business with. If you’re on the fence about a tuning product, give the ThunderMax® a try. You’ll be glad you did!”

Get a ThunderMax® on your bike… you won’t regret it! You’ll be smiling all the way home from Sturgis!”

Bought my ThunderMax® in ‘06 for my standard ‘05 FLHTI® when the dealer said I had to buy the H-D® Race Tuner. I love to solve my own problems, so I purchased a ThunderMax® unit. After setting up (easy process) I was amazed how good my bike ran. With a 95” kit, S&S cams, Rinehart exhaust, and my bored out throttle body. A year later, I added the AutoTune for even more simplicit. I’ve changed maps several times, and the AutoTune always works to fine-tune the map. 60 K on the bike and it runs excellent! A positive investment!

The ThunderMax® has made my 2012 Street Glide® the best running bike I have ever owned. I wasn't sure if ThunderMax® would live up to what I read and saw, but it is all that and much more. Great product if you have a Harley® Throttle –By-Wire. Get one now and you will not regret it.”

ThunderMax® is awesome! It really made a huge difference in the performance of my bike. I get quicker throttle response, and better gas mileage. I also installed true duals and bigger cams.”

I have a 2011 Road Glide with a ThunderMax® module and Red Shift® cams. I rode a stock one the other day and it felt like I was on a bicycle. Those two mods are more than worth the price of admission. You can never go wrong with the talent at Zipper’s!”