Keefer Tested: JGRMX Stage 2 Kit for RM-Z250/450

JGRMX Stage 2 Kit for RM-Z250/450

If you’re the owner of a Suzuki RM-Z450 or 250 this is something that definitely should interest you. When I go to the track I don’t see many Suzuki’s, but the Suzuki’s riders I do see, it’s almost like they flock together and have some kind of brothership. It’s kind of like if you drive a Jeep and you pass by another Jeep you all have this secret wave or something. One Suzuki rider sees another and they instantly talk about their bikes, how it’s set up, and if they are going to do any mods to it.

Well recently I had the chance to join that special gang and took some RMaRMy members to Perris Raceway, to ride JGRMX’s stage 2 engine kits, (for the RM-Z250/450) to see if these engine mods are a noticeable difference for the cost. Below is a brief synopsis of each machine, each rider’s opinion, and a breakdown/pricelist of each kit that is available from JGRMX. If you want to learn even more about each JGR kit, check out the Keefer Tested Podcast that will be available on 6/24/19 on all your usual podcast apps.

Test Riders:

Adam Enticknap: Professional Supercross rider.

Joe Oehlhof: Keefer Inc. test rider and responsible for the 2019 RM-Z 450 test bike.

Dallas Dunn: Real world 2019 RM-Z 450 owner/heavy equipment operator.

RM-Z 450:

We first rode the stock RM-Z450 for a baseline feel and again noticed that the bike is good, but just wasn’t that exciting to ride. Once each rider got on the JGR bike all of them agreed there was a huge difference in engine character.

From the first kick, it felt and sounded much different from the stocker. Upon entering the track you could immediately tell there was more RPM response as well as connection to the rear wheel. The engine character was also much more free feeling and had less engine braking than the stock engine. Each gear not only revved out farther, but the JGR engine made less work for our riders because they simply didn’t have to shift as much. We wouldn’t describe the power as explosive, and that is a good thing because it is extremely difficult t orange that type of power for a long moto. Overall the quicker, snappier, free-revving engine made the RM-Z450 easier to ride fast and also made the machine feel lighter because of how responsive it was. Having a lighter feeling Suzuki is like finding gold in your backyard. It’s almost un-heard of… However, this JGR stage two engine character makes it feel playful on the track.

RM-Z 250:

With the modified RM-Z250, we had two ECU maps to try (on the 450, Suzuki/JGRMX only loaded one), but both maps felt very similar. The second map made the JGRMX Suzuki 250 rev out slightly farther, but had less RPM response. Just like the 450, the 250 had more power everywhere and a more free revving engine. Getting a free revving 250 four stroke is super important because you need as much excitement as you can get with the smaller engine. With the 450 you’re looking to control all that power and with the 250 you want as much as you can get. Compared to the stock RM-Z 250 this JGR engine is not even comparable. When an older 190 pound, non 250cc four stroke, vet rider tells you that he would love to race this bike at local races, you know it’s legit. The beauty of this JGR engine is that you can lug it more than the slow revving stock engine because it has so much more recovery. If you’re running third gear in the corners and the RPM’s fall off, a simple clutch lever flick will get you back into the meat again. Each rider that swung a leg over this JGR RM-Z 250 couldn’t believe how much it changed from the stock engine.

Rider Opinions:

Joe Oehlhof: The JGR phase 2 motor mods for the Suzuki RM-Z 250 were a huge improvement in every aspect of the powerband. The stock power was decent, but it was just in a small window of the power band. It took a lot of effort and constant thought to keep the power in that sweet spot. If you didn’t shift in the right spot or weren’t in the right gear the power fell off and took effort to pick it back up. The JGR motor had great power down low, through the mid and top with a free revving feel and very little engine braking. I was able to over rev the bike in second and it still made power. I could also lug the bike in 3rd and carry momentum and the power was right there with a crack of the throttle or fanning the clutch. The free revving motor also seemed to unwind the chassis a bit and gave it a more plush, less rigid feel.Very impressive and fun to ride.

The 450 JGR motor was also a big change and took the very very linear powerband of the stock engine and turned it into an exciting, broad, very usable and connected motor. The stock motor is under powered compared to the other 450s and it also has a small window of power and needs to be short shifted. Additionally it has a tight held back feeling and noticeable engine braking. The JGR mods free’d the power up, got rid of engine braking, made power gains throughout the entire curve, and made a very broad usable power. It had good torque and “snap” down low that gave the bike a very light feel as opposed to the heavy sluggish feel of stock. As with the 250 the free revving motor also unwound the chassis a bit and gave it a plush, less rigid, more forgiving feel. Coupled with a confidence inspiring chassis and great turning characteristics, these motor mods turned RMZ 450 into an exciting bike and legitimate race weapon.

Adam Enticknap: I only tested the 450 because frankly I couldn’t give you that much of an opinion on a 250 since I haven’t ridden one in forever. The JGR Stage two engine package on the 450 made the bike more exciting to ride, gave me that race bike feel that I love, as well as let me work less on the track compared to the stock engine. The rear wheel connection is also better than stock, but it has more snap that I need coming out of corners. I would say this stage two kit is pretty damn close to what I like in an engine, but I would want just a little more bottom end.

Dallas Dunn: The JGR RM-Z 250 was night and day difference over the stock bike. First thing I noticed was there was no delay in throttle response like the stock bike had. It almost felt like a “bog” feeling on the bottom end, with not a lot of excitement. The JGR bike had a lot of power down low and I was able to ride in a higher gear. The JGR bike had a good free feeling with less engine braking along with a better balanced suspension feel that worked a lot better. This must of had something to do with the engine character.

With the RM-Z 450 I noticed a big difference in throttle response just riding over to the track. The stock bike has good smooth power, but the JGR bike definitely hit way harder and still had that smooth crispy feel. At first I couldn’t ride this bike as fast as the stock bike, but after coming back in and jumping on my personal 2019 RM-Z 450 I could see some of the benefits of having this newfound power. I took some laps to see the difference between my bike and the JGR bike and I noticed the bike had less engine braking as well as less pitch coming into corners. Adam told me to try riding a gear higher with the JGR engine and that seemed to help a lot! With my bike and the stock bike you would need to be in a lower gear and get on the gas harder. The JGR bike would just pull no problem a taller gear without an issue. The JGR 450 also had a lighter feel as I noticed better tip in through corners. After my second time out I liked the JGR 450 a lot more than my first time out. I think if I had more time on it I would love it, but for me I think it is too pricey. This kit would really be a nice upgrade for the serious racer, but I am simply not that guy. I race only a few times a year and ride twice a week, so know I would benefit more from the stage 1 package. I am currently looking into purchasing that right now thanks to this test. Thanks a lot Kris!

JGRMX SUZUKI PRODUCT LINE

JGRMX SUZUKI CYLINDER HEAD ASSEMBLY

2019-‘20 SUZUKI RM-Z250: $2,299.99

2018-‘20 SUZUKI RM-Z450: $2,399.99

The JGRMX ported cylinder head assembly is derived from the professional race team and assembled by the team’s engine technicians. Ported using CNC milling creates the exact performance specifications that top racers demand. The head was developed over six months of rigorous testing through dyno and on-track research. A JGRMX race-spec camshaft kit is included, as well as the OEM/stock valve train and cam gears to improve durability and ease maintenance.

We recommend the use of a GET RX1 PRO ECU and JGRMX high-compression piston with our cylinder head assembly for best results.

CNC ported cylinder head
Developed by the JGRMX race team
Fully assembled by JGRMX engine techs and ready to install
JGRMX race camshaft kit is included
Uses stock valve train and cam gears (valve springs are appropriately shimmed [450] or exchanged for proper valve control [250])
JGR logo engraved on side of head
Includes head gasket, base gasket & NGK spark plug
Hinson clutch springs are suggested
Requires the use of VP Racing T4 fuel
Available for the 2019-‘20 RM-Z250 and 2018-‘20 RM-Z450

JGRMX SUZUKI STAGE 1 KIT

2019-‘20 SUZUKI RM-Z250: $1,049.99

2018-‘20 SUZUKI RM-Z450: $1,179.99

Boost overall horsepower and improve engine tuning ability with the JGRMX Suzuki Stage 1 Kit. The kit contains JGRMX’s proprietary high-compression piston kit, along with a GET RX1 PRO ECU. The ECU comes pre-programmed by JGRMX’s engine experts, with two maps that are designed specifically for JGRMX’s performance modifications. A map switch mounts to the handlebars and allows the rider to easily toggle between maps.

Piston boosts engine compression (RM-Z250 – 14.25:1; RM-Z450 – 13.5:1)
Two-ring design provides less drag and more horsepower
Forged piston for increased durability
Machined valve pockets for additional valve clearance
JGR logo etched on the piston crown
ECU comes pre-programmed with two map options (mapped for VP Racing T4 fuel)
Plug-and-play with immediate performance benefits
Maps developed specifically for JGRMX engine modifications
Kit includes high-compression piston, rings, DLC coated wrist pin, clips, and GET RX1 PRO ECU (with WiFi-Com, two-position map switch and installation instructions)
Available for the 2019-‘20 RM-Z250 and 2018-‘20 RM-Z450

JGRMX SUZUKI STAGE 2 KIT

UPDATED: 2019-‘20 SUZUKI RM-Z250: $3,349.99

UPDATED: 2018-‘20 SUZUKI RM-Z450: $3,549.99

For the ultimate performance advantage, the JGRMX Stage 2 Kit contains the components necessary for success on the amateur ranks and professional level. The kit contains the JGRMX ported cylinder head assembly, JGRMX-spec race camshafts installed, as well as a pre-programmed GET RX1 PRO ECU and JGRMX high-compression piston kit. The Stage 2 Kit bolsters engine horsepower throughout the entire RPM range without sacrificing durability.

CNC ported cylinder head
Developed by the JGRMX race team
Fully assembled by JGRMX engine techs and ready to install
Kit includes assembled cylinder head, JGRMX-spec camshafts installed, GET RX1 PRO ECU (with WiFi-Com, two-position map switch and installation instructions), JGRMX high-compression piston kit, head gasket, base gasket and NGK spark plug
Uses stock valve train and cam gears (valve springs are appropriately shimmed [450] or exchanged for proper valve control [250])
JGR logo engraved on side of head
Includes head gasket, base gasket & NGK spark plug
Hinson clutch springs are suggested
Requires the use of VP Racing T4 fuel
Available for the 2019-‘20 RM-Z250 and 2018-‘20 RM-Z450

JGRMX SUZUKI HIGH-COMPRESSION PISTON KIT

2019-‘20 SUZUKI RM-Z250: $299.99

2018-‘20 SUZUKI RM-Z450: $334.99

Developed in collaboration with JE Pistons to JGRMX’s exact specifications, the RM-Z250 high-compression piston bolsters performance throughout the entire RPM range. Machined valve pockets allow for additional valve clearance when used with higher lift camshafts. The kit includes piston rings, a DLC coated wrist pin, and clips. The JGRMX high-compression piston can be used in OEM/stock engines and most modified RM-Z250 and RM-Z450 applications. Use of minimum 100-octane is required.

Piston boosts engine compression (RM-Z250 – 14.25:1; RM-Z450 – 13.5:1)
Two-ring design provides less drag and more horsepower
Forged piston for increased durability
Machined valve pockets for additional valve clearance
Kit includes piston rings, DLC coated wrist pin, and clips
JGR logo etched on the piston crown
Available for the 2019-‘20 RM-Z250 and 2018-‘20 RM-Z450

GET RX1 PRO ECU

MSRP: $899.95

The GET RX1 PRO ECU is the perfect mixture of technology and flexibility, with two pre-programmed maps installed by JGRMX professional engine technicians. This plug-and-play product is mapped specifically for JGRMX’s performance engine modifications for the 2019 Suzuki RM-Z250. The GET RX1 PRO is the best way to help get maximum output from your engine. Included in the kit is a WiFi-Com and two-position map switch, along with installation instructions.

Comes pre-programmed with two map options
Plug-and-play with immediate performance benefits
Maps developed specifically for JGRMX engine modifications (using VP Racing T4 fuel)
Kit includes WiFi-Com, two-position map switch and installation instructions
Available for the 2019-‘20 RM-Z250 and 2018-‘20 RM-Z450

JGRMX SUZUKI RM-Z250 CARBON FIBER SKID PLATE

MSRP: $299.95

Protect your Suzuki RM-Z250 engine cases, water pump and ignition cover with the carbon fiber skid plate. Made using multiple lays of 100% carbon fiber, the skid plate comes with rubber grommets and black anodized aluminum shoulder washers. The skid plate uses the same mounting holes as the OEM/stock plastic engine guards, making installation simple. This is the exact same skid plate that the JGRMX/Yoshimura/Suzuki Factory Racing racers use.

Crafted from 100% carbon fiber
Comes with rubber grommets and aluminum shoulder washers installed
Protects engine cases, water pump and ignition cover from damage
Pre-drilled holes for easy access to lower frame cradle nut and bolt, and bottom engine mount hardware
Available for the 2019-‘20 RM-Z250

JGRMX SUZUKI RM-Z450 CARBON FIBER SKID PLATE

MSRP: $299.95

Protect your Suzuki RM-Z450 engine cases, water pump and ignition cover with the carbon fiber skid plate. Made using multiple lays of 100% carbon fiber, the skid plate comes with rubber grommets and black anodized aluminum shoulder washers. The skid plate uses the same mounting holes as the OEM/stock plastic engine guards, making installation simple. This is the exact same skid plate that the JGRMX/Yoshimura/Suzuki Factory Racing racers use.

Crafted from 100% carbon fiber
Comes with rubber grommets and aluminum shoulder washers installed
Protects engine cases, water pump and ignition cover from damage
Pre-drilled hole for radiator breather hose routing
Available for the 2018-‘20 RM-Z450

JGRMX SUZUKI CLUTCH COVER BY HINSON RACING

MSRP: $169.99

Hinson Racing has an outstanding reputation for quality and performance. Hinson and JGRMX have teamed up to offer a Billetproof clutch cover that’s laser etched with the JGR logo and used by the JGRMX/Yoshimura/Suzuki Factory Racing Team. The clutch cover improves heat dissipation, is stronger than stock, and is precision machined from billet T-6 aircraft quality aluminum to aerospace tolerances. An aluminum oil fill plug is included.

Machined from billet T-6 aircraft quality aluminum
JGR and Hinson Racing logos laser etched on the cover
Includes aluminum oil fill plug
Cover improves heat dissipation and is stronger than stock
Used by the JGRMX factory race team
Available for the 2019-‘20 RM-Z250 and 2018-‘20 RM-Z450

JGRMX SUZUKI CLUTCH SPRING KIT BY HINSON RACING

2019-‘20 SUZUKI RM-Z250: $59.99

2018-‘20 SUZUKI RM-Z2450: $69.99

Manufactured by Hinson Racing, the Hi-Temp Clutch Spring Kit provide optimum hookup with minimum heat build-up. Developed to enhance the performance of any Hinson Clutch Component and your stock clutch alike, the spring kit works with all OEM parts. The springs are manufactured from high temperature steel, and are highly resistant to losing their strength due to the high heat of today’s four-strokes.

Race proven by the JGRMX race team
Springs manufactured from high temperature steel
Highly resistant to losing their strength due to high heat
Provide optimum hookup with minimum heat build-up
A must-have for increased horsepower engines, heavier riders, and/or deep track conditions
Work with all OEM parts
Suzuki RM-Z250 clutch spring kit contains five springs; Suzuki RM-Z450 kit contains six springs

JGRMX SUZUKI ADJUSTABLE PULL ROD

MSRP: $279.99

The JGRMX adjustable pull rod is a sound investment. JGRMX offers four different pull rod length settings thanks to our adjustable pull rod design. Choose from stock length, all of the way to 1.5mm longer than the stock length (135mm). Length adjustments are in 0.5mm increments. This allows for fine-tuning of the bike’s handling characteristics. The longer pull rod is especially efficient in changing the rising rate of the rear end, thus preventing a wallowing sensation under a heavy load.

The JGRMX Suzuki RM-Z250/RM-Z450 adjustable pull rod is machined out of billet 2024 aluminum, and then hard anodized for a brilliant color finish and durability. Every adjustable pull rod comes installed with bearings, seals and washers. Detailed instructions are included.

Adjustable length allows for fine-tuning of the bike’s handling characteristics
Machined out of billet 2024 aluminum
Hard anodized for brilliant color finish and durability
Installed with bearings, seals and washers
Detailed instructions included
Available for the 2019-‘20 RM-Z250 and 2018-‘20 RM-Z450

JGRMX SUZUKI CASE SAVER

MSRP: $29.95

The JGRMX Suzuki case saver is designed specifically to protect the bike’s left-side engine case from damage. Laser cut out of high quality 6061 aluminum and hard anodized in a dark bronze color, the case saver is like buying insurance for your engine. The JGR logo is laser etched on the outer face. Shorter bolts replace the OEM/stock length bolts and are included. Used by the JGRMX factory race team.

Constructed from 6061 aluminum
Hard anodized for added strength
JGR logo laser etched
Shorter bolts replace the OEM/stock length bolts
Available for the 2019-‘20 RM-Z250 and 2018-‘20 RM-Z450

JGRMX SUZUKI GRAPHICS KIT

MSRP: $149.95

Dress up your Suzuki RM-Z250 or Suzuki RM-Z450 with the JGRMX Suzuki graphics kit. Made from 21 mil thick matte material, using Substance FLO Technology to eliminate bubbling, the graphics are very easy to install and extremely durable. The kit includes graphics for the shrouds, fenders, fork guards, airbox, swingarm, generic number plates and fuel tank cover.

21mil thick matte material, utilizing Substance FLO Technology, to help eliminate bubbles for easy application.
Kit includes graphics for the shrouds, fenders, fork guards, airbox, swingarm, fuel tank cover and generic number plate decals.
Made by Armored Graphix
Available for the 2019-‘20 RM-Z250 and 2018-‘20 RM-Z450

JGRMX SUZUKI SEAT COVER BY GUTS RACING

MSRP: $69.90

Made by GUTS Racing, the high-tech diamond pattern gripper material provides excellent traction. The cover is formed to fit the seat for easier installation and sewn with high strength nylon thread for lasting durability. Six ribs have been sewn on for added strength and traction. JGR logo rubber patches on each side complete the race look.