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Motorcycle Kits ATV / UTV Kits Head Repair & PortingOrder Form

2-Stroke Price Reductions!

Supermini mods from $499 and big bike mods from $549.  Click the motorcycle button to find your model.


Big Bore Kit
4-stroke cylinder re-plate for $190

You can’t buy a new cylinder for that !!

15% off piston and gaskets with re-plate.




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Home of the ICE CUBE Cylinder

Ice Cube CylinderThe only cylinder kit designed from the beginning for big bore/stroker applications!!
Advantages/Features of the ICE CUBE

  • Increased water capacity helps reduce engine temperatures
  • Billet aluminium outer cylinder increases heat transfer
  • Re-useable rubber head gaskets. (some models)
  • Ceramic nickel plated cylinder bore
  • Polished/anodized exterior (color options available on most models)
  • Forged/plated aluminium sleeve
  • Thicker stronger cylinder skirt design allows for stroker crankshafts



!!! All Wiseco Catalog Parts 15% Off !!!

This offer good on e-mail orders only!Wiseco 20% off
E-mail us your request to:

Find your parts in the Wiseco Catalog and e-mail us part #’s or e-mail us your year, make , model, and your desired parts.
We’ll look it up for you and reply to your e-mail on the next business day.

Max Power RPM’s

Big Bore KitMax Power Inc. offers the largest selection of big bore kits for motorcycles and ATV’s anywhere. Home of the Ice Cube cylinder. Max Power has big bore and stroker kits available for both 2 stroke and 4 stroke engines. We are also your one stop engine performance shop selling stock displacement performance modifications, high compression pistons, Hot Cams, Web Cams, Athena big bore kits, Hot Rods stroker crankshafts, Empire exhaust systems,  Wiseco pistons, CP Pistons, and Cometic gaskets.





About Us

Company History

Max Power and Rick Peterson Motorsports have merged to become MaxPower-RPMs. This merger combined Max Power’s ATV Racing and Cylinder Re-plating experience with Rick Peterson’s engine design knowledge and Motocross industry background. Here is a brief history of each company.


Max Power

Max Power opened the doors in Madison Wisconsin in 1997. Originally intending to plate cylinders for the many small engine manufacturers located in Wisconsin, Max Power specialized in plating cylinders.  The ability plate and re-plate cylinders naturally developed into building Big Bore kits for Motocross bikes and eventually ATV’s.    

Rick Peterson Motorsports (RPM’s)

Rick Peterson began building Big Bore and Stroker Jet Skis in the mid 80’s. In 1994, he built the first YZ167. Cycle News tested it and liked it so much they put it on the cover. The kits began out-selling the Big Bore Jet Skis, so Rick began building them full time.

RPM’s bought Nikasil-USA in 1997 and Rick’s staff of 12 began plating cylinders in-house, as well as stroking and balancing cranks, porting cylinders and testing all promising performance parts on the dyno and the track.

In 2002, Rick built the first YZ302F. Dirt Bike called it “a great Vet Machine. Truly impressive. TWMX rated the YZ302F a “10” and called it, “The funnest Bike of all time.” Rick agreed, and was hooked on the Big Bore 250F’s. Soon 4-stroke sales eclipsed 2-stroke kit sales.

In 2004, Rick built the first ICE CUBE cylinders. This was no small feat. It required the purchase of over $100,000.00 of CNC equipment and many late nights! The ICE CUBE was a work of art. (Ok, maybe not the first one!) It is billet aluminum with a nikasil plated liner that allowed Rick to build Big Bore Kits that were cool looking and durable too.

At this time Rick was talking to Max Power about moving the 2-stroke line to Wisconsin so he could focus on his new passion, the ICE CUBE Cylinder.   


In November 2004 Max Power moved the RPM’s line of 2-stroke kits to Wisconsin.  Over the next 7 months Rick Peterson trained the Max Power staff on his kit specifications and on his trade secrets for developing future kits to the highest standards in the industry.

In June 2005, Max Power completed the purchase of RPM’s 4-stroke line and moved all of the 4-stroke parts and services to Wisconsin as well.  Rick stayed on with Max Power until June 2006 to complete the transition and as a consultant until 2008.

In February of 2009 Max Power-RPM’s was purchased in a management buy-out by two employees.  It was operated out of the same shop in Madison until July 2011 when it moved to the current location in Morrisonville Wisconsin. 

Max Power-RPM’s is more focused on performance engine modifications than ever before.  We still sell and service every kit that has ever been sold by both Max Power and RPM’s.  We also have improved and expanded our line of “Stealth” cylinders that combines the internals of the ICE CUBE and the exterior of the OEM cylinder. 

We currently provide cylinder plating services, welding repairs, complete head repair services, cylinder sleeving services, cylinder boring, cylinder porting, cylinder head mods, crankshaft repairs, crankshaft stroking, and balancing.  

The guys you talk to on the phone are the guys doing the work.  We take pride in giving you the best value for your dollar and the truth no matter what.   

Please let us know what we can do for you!

Motorcycle KitsATV / UTV Kits




What is your shipping address?

UPS and Fed Ex Use:

Max Power Inc.

7841 Morrison St.

Morrisonville, WI 53571

Attn: Incoming Goods



Max Power Inc.

PO Box 183

Morrisonville, WI 53571

Attn: Incoming Goods


How long does cylinder plating take?

Cylinder repair generally takes two weeks depending on workload and the amount of damage to the cylinder.


How long does it take to have a big bore kit completed?

Big bore kits are typically completed in two and a half weeks, stroker engines take about three weeks.


What about studs, power valves and dowel pins?

For basic cylinder repair, please remove all steel components, if you cannot remove them, Max Power will take them off and put them back on your cylinder for an additional charge.

For big bore kits, leave all steel components attached to the cylinder. Max Power staff members will remove the parts, modify them if necessary, and reassemble the cylinder at no extra charge.


Can you sleeve my cylinder?

Yes, Max Power offers a full cylinder sleeving service as well. We do not recommend this method of repair, but will perform the work if necessary. Many of the four stroke big bore kits Max Power produces are created by implementing a larger outside diameter aluminum sleeve. Once the aluminum sleeve is installed, the bore is then coated with Nickle Ceramic Plating. Nickle Ceramic plating has many advantages over steel liners. Wear resistance, lower running temperatures, reduced friction and better oil retention are just a few of the benefits of plating over a steel sleeve.


Does cylinder repair include a new piston and gasket kit? What about big bore kits?

Cylinder repair does not include a new piston kit and gasket set, however we carry a full line of pistons and gaskets. The advantage to purchasing a piston with your repaired cylinder is that your cylinder will be custom fit to the piston that you purchase. Max Power measures and custom hones every cylinder to exact clearances based on piston size.

Why take a chance of having your finished tolerances any less than perfect? All Max Power big bore kits include a piston kit and gasket set, and will automatically include the custom cylinder honing process.


My piston kit came with too many rings. What ones do I use and how do they go?

Some ring sets that come with our piston kits are used for other applications that require additional rings. The gold or chrome ring always goes on the top with the marks facing up. The black ring is an optional oil scraper ring and goes in the middle. If it is marked then install it with the marks facing up. If there is no second ring land, throw the black ring away, it is not used.


What is the required jetting for my big bore / stroker kit?

The jetting for your kit will be listed on your invoice. In some cases it will not be listed because it does not vary from stock. It is impossible for us to give you exact jetting specs for every year machine with every year head cam and porting spec, but what we list will get you close. We also are available Monday through Friday to help you get it dialed in. Please have your invoice # handy so we can reference it before giving assistance. For a handy jetting guide we found on the internet click here.


Is there a special install procedure for a big bore or stroker kit?

Typically our kits will install the same as OEM parts with the same torque specs. Depending on the kit you purchase there may be extra work required to make a kit fit properly. The main thing to remember is DO NOT FORCE ANYTHING. If it does not fit then stop and call us. We are modifying the engine and making it bigger. This means we are filling up the gaps in the engine with bigger parts. Sometimes the case castings vary and it is necessary to clearance them a bit for proper fit. Sometimes parts flat out need to be modified. Here are some rule of thumb measurements to help you out. Keep a minimum of .005” for static parts (piston skirts to cases), a .030” gap between rotating parts(rod to case), and a gap of .025” for reciprocating parts(piston to case). If you have questions call us.


What kind of oil should I use?

For 4-Stroke engines we recommend high quality petroleum based motorcycle oil. Many of the non-synthetic OEM engine oils work well and allow the rings to seat quickly. Do not use full synthetic or semi-synthetic oils for break in they are too slippery and keep the rings from seating on the bore. For 2-Stroke engines we recommend Yamalube R mixed at 32:1, we have no confidence in wild 50:1 or 80:1 claims by oil manufacturers. Oil is cheap and piston and cranks are not.


What is the break in procedure on my new engine?

When starting a cold engine NEVER rev it up higher than a fast idle. Put a fan in front of you radiators and blow air through them. Get the engine started and let it idle until the water in the radiator is as hot as the water you would wash dishes in, stop the engine and let it cool off. Do this 3-4 times. After this is done ride your engine under light loads varying the rpm but do not go beyond ¾ throttle until you have about 30-45 minutes on the engine.


What octane fuel should I run?

In most cases we recommend a 50/50 mix of 110 octane race fuel and premium pump fuel for about a 100 octane rating. Engines run the best and make the most power and run the hardest with just enough octane to prevent detonation.


How long should I go before changing my piston?

There are way too many variables involved for us to give you a blanket time frame for piston changes. Air filter and engine oil maintenance (or lack of) as well as, intake tract condition, riding conditions, jetting, riding style, and fuel used all plays a huge role in engine life. What we can tell you is that DIRT, HIGH RPM’s, and TIME are the main killers of off-road engines. Too much of any of these will kill your engine.

Two strokes are the easiest to monitor because we can measure the compression. Measure the compression when the engine is fresh and document it. Then periodically check the compression of the engine with the same gauge. Once the compression drops about 10% it is time to change the piston. For more details click here.

On four stroke engines it is necessary to tear down periodically and inspect piston to wall wear and ring wear. Initially we recommend following the OEM specs. This is usually 12-15 hours of run time. After inspecting and calculating wear a more accurate maintenance schedule can be determined. It is always better to tear down early. Follow your OEM manual for wear limits. Feel free to call us if you have questions about your kit. Please have your invoice # for easy reference.


Send us your reviews and we will send you a Max Power-RPM’s T-shirt!


Submitted on Friday, September 20, 2013 8:23 PM by Dylan Rice

2003 CR125 porting and head mods

“I had MaxRPMs port/polish my motor and re-chamber the head a while back.  I run it on straight VP110 gas.  Man that thing is fast!  I think it will take my 2012 CRF250.  Just wanted to say thanks!!  Made a big difference!”


Submitted on 2013/03/01 at 8:38 am by Ray Baldwin

I thought I would send this photo to you I really do love my 285 Yamaha you should be able to see your stickers and the #285. Love this bike I have put over 4200 off road miles, since August and in the last 3 years I have over 11,000 miles on this cylinder. This is not easy gravel roads it is single tracks and atv trails, in the Colorado high country, and single track and desert riding in the Moab Utah area. I installed a wide ratio transmission I.E. wr450 3rd-4th-5th with one tooth larger that stock on the back it still does over 80mph. The 285 has more than enough torque to pull the higher gears no matter where I am, high country or desert. This bike shocks everyone with the 450s as that they just can’t get away from me. 🙂

It seems like after I ride with them, the next time I see them they have a pipe or new ignition set up or something else to increase the output of their 450’s.”

Submitted on 2013/02/11 at 8:23 am by johnboy

“02 yz 167 from these guys
I have never rode a more well ballanced bike with the power of a 450…you can burn up the hills or just putt around the yard,,my buddie wanted to go riding,,,hes got a yz250f,,he said lets go if you can keep up…and laugh at me,,,,after he caught up a mile later with his mouth open,,,,never to say ,,,,he was trying his best to buy it…very very good match this motor is to the yz125,,,,thanks guys”

Submitted on 2012/07/05 at 9:27 am by Grumpy18

“I have been running the 498 kit on my 02 Honda 450 for around 5yrs, its been awesome! I mainly ice race it but a few times a year hit the tight trails. The 498 make gobs of mid-range torque and on mine big top end power. When people notice the billet cylinder it creates alot of talk in the pits! Extremely happy with this product, just picked up another bike and going to try the 523 kit this time. Thank you Max Rpms for a great product!”

Submitted on 2012/05/15 at 8:26 am by Andreasen Racing

“Just Plain Awesome !
This is just plain awesome. I now have the power to go and do what I want with a 125. I’m an old “master” or “super senior” or whatever you want to call a 50+ racer, and I love the fact that I can have the power to get myself into trouble & the power to get myself back out. Even with a desert tank on it, the bike still weights less than any 450 and most 250f’s. It is just plain fun to ride! My only issue was getting it jetted, but Josh helped me out when I needed it. I put an 11oz. flywheel on and the bike will crawl over most any obstacle. With this flywheel on it , it doesn’t rev out as fast and hitting the clutch doesn’t get it spinning like a 125. I think I’ll get an 8.5oz flywheel and try it. I’m running a Barnett basket and the clutch has never been so smooth, even stock. I run a V-Force 3 and an i-boost and response is right now. I use this bike to desert race and trail ride and am so impressed that I don’t think I will get a bigger bike in the future. THIS IS TOO MUCH FUN!
Dennis Andreasen”

Submitted on 2012/05/08 at 9:33 am by Eric Tinker

“We are 100% pleased with Tim and Josh. The motor is beyond expectations. Very reliable very strong. Our PR2 motor blew up too many times so we tried the Max Power big-bore (very good motor) then upgraded to the 105 stroker. Absolutely NO problems. We love these guys! Eric Tinker RM105/YZ125”
Submitted on 2012/02/20 at 8:28 am by Scot

“I have had 4 of these, and they are so much fun you cannot even describe it! My current 167 is an 09 that was set up for torque by MAX POWER, and I ride desert and mountains – I dropped 6 teeth in the rear and up 1 tooth in the front, so it is geared really tall, and it handles everything from gnarly, rocky, 1st gear 2 MPH hills to wide open desert, where my top speed is greater than most 450′s. I can do any hill that a 450 can do, unless it is a pure horsepower hill – deep sand or something like that. I can take off from a standstill in 6th gear with no major drama.

Too Much Fun!
I can turn inside everyone. If we get into a boulder patch and get stuck, I can pick my bike up and move it, as it weighs 40 lbs less than most bikes…
I’ll be riding these til I drop.”

Submitted on 2011/11/01 at 8:36 am y Trail Rider

love the power that the yz285 puts out compared to my stock 250. it lifts wheels shifting down the road all the way to 3rd gear. looks good on my bike and cant stop saying it but its so powerful. i blew my friends honda trx450 away in a drag race. would highly reccomend this kit without doubt. need to wear goggles cause the wind makes your eyes stay shut its really that fast.”

Submitted on 2011/02/23 at 8:35 am by Scorr Racer

“yz 285
I love this kit just got ours re done last week and this thing is so quiet and it just shines anywhere no matter what the conditions. woods or moto. it can kick a 450s but any day. Love it Thanks RPM!”

Submitted on 2010/09/24 at 8:17 am by Kawi Rider

“This is the most awesome mod motor ever. It starts easier than stock, it pulls hard and forever on the top. I have had no issues and will do it to my next 250f. Many mods you lose either on the top or the bottom, this thing rips everywhere!!!!”

Submitted on 2010/07/26 at 8:34 am by Raymo

“Your friend will be bummed. I have been running the 285 kit on my 05 250 for almost two years this last fall I put a wide ratio tranny in my Yamaha. I have a friend that just got a 09 450f. No matter where we race he can only beat me on top end IE over 75 MPH we are running the same gearing IE stock for the kx 13-50 I’m running the same on my 285. He just shakes his head,and says that thing is really fast. So last week he ordered a new bomb header and new computer programmer. He says it is only to make it start better. But i know the truth he can’t stand that my lowly 285 yz is a fast as his brand new fuel injected 450f. I highly recommend the staff at Max RPM they have been awesome to deal with.”

May 2008mag_1

Dirt Wheels: TRX522 – We don’t build em much harder than this!

“It has stump-pulling power down low like you wouldn’t believe. Then, it hits a monster mid-range surge that has you hanging on for dear life. The motor pulls so hard you have to make sure you have a firm gripon the handlebars, otherwise, look out mama! Next thing you know, you’re revving out on the top end, and going so blindingly fast that it is all you can doto find the brakes, and get it slowed down in time to make your turn. You know what we call that? FUN!”

Please click here or on image for complete article


mag_1May 2008

Motocross Action: RM-Z 276 Stealth”It’s a light weight, flickable bike that scores an unanimous 10 from the panel of fun judges.”

Please click here or on image for complete article







January 2008

ATV Action: LT-R 550
Maxpower/RPM’s is known for building some of the most powerful ATV motors around. We know that. So when we got a call from Maxpower asking if we wanted to test their new LTR stroker kit, we tried to stop giggling like schoolgirls. We waited for weeks to get our hands on what we were sure would be the fastest 450-chassis quad we’ve ever ridden, and when we finally got our hands on it, we didn’t know what to do with ourselves…

Please click here or on image for complete article


October 2007

Dirt Bike Rider UK: KXF276

Click here to see the article
mag_1July 2007

Motocross Action: YZ285
“Could our Max Power YZ285 beat the 450 four-strokes in hand-to-hand combat? With a motivated rider it would be “mission accomplished””

Click here to see the article




mag_1June 2007

Dirtwheels: LT-R 498
“The power came on smooth, and strong all the way through the mid-range and right up to the very top end.”

Click here to see the article
December 2006

Dirtwheels: TRX 522R vs. TRX 488R.
“This mod(TRX488) transformed our stockish TRX450 motor into one of the easiest-to-ride, blazingly fast, monster


powerbands of any modified Honda engine we have ridden in some time.” “In a word, perfect power. Well, make that two words.”

“When we put a stop watch on our pro-level test rider(riding the TRX522) he consistently cut lap times that were two to four seconds quicker per lap. In ten laps that translates to 20 to 40 seconds time. A sizeable sum that would put you at the finish line well ahead of an equally skilled rider aboard the 488 kitted machine.”

Click here to see the article


December 2006

Quad Off-Road Magazine: Maxpower/RPM’s YFZ523
“By the end of our test session the Max Power-RPMs YFZ523 had made believers out of us. Previous to this, our test rider had a bias against big bores, but he admitted at the end of the ride that he would own this YFZ and would be excited to ride it at the dunes, on the trails, or any of his other local riding spots.”

Click here to see the article


December 2006

ATV Sport Magazine: TRX522
The biggest advantage of the ICE CUBE was its pulling power and ability to lug gears. Our test rider noticed power strikes right on the bottom end and hard pulling all the way through the power band!

Click here to see the article


October 2006

Motocross Action: CRF264 Stroker

“MXA’s biggest concern with big engines is the powerband. If done wrong, the engine starts to feel like a small 450 instead of a big 250. It loses rev on top, gets chunky in the middle and decelerates like a steam engine. Luckily, this isn’t the case with MaxPower’s 264 kit. It doesn’t lose any of the CRF250’s inherent traits—it just adds a ton of torque.”

Click here to see the article



mag_1September 2006

Dirtbike Magazine: KX276F

“Whoa! First off, this has to be the easiest starting four-stroke that we’ve tested. Power wise there is no comparison to the stocker; the CUBE hit harder, sooner and has meat. It craves a higher gear, pulls the cog with apparent ease, and gets with the program post haste.”

Click here to see the article