Magic Touch

2005 Tom Morgan Racing Suzuki RM-Z250

Every year, TWMX does a number of bike hop-up tests to explore the true potential just waiting to be unleashed from the stockers. We use a couple very diplomatic systems to pick the aftermarket companies that will perform their magic on the bike at hand. Our favorite of systems is quite simple: Which bike are we looking to untap? Who’s fast on said model? And who’s stuff are they using? For the 2005 RM-Z250, we needed to look no further than Team Motoworld Racing. Chris Gosselaar, Eric Sorbey and Brandon Jesseman have been putting in some impressive rides aboard their Tom Morgan Racing, Race Tech-suspended RM-Zs, so we wasted no time and quickly rang up our homie and long-time race mechanic Dave Dye to get the wheels in motion.


Dave called legendary race mechanic and hop-up guru Tom Morgan of TMR, and asked him to work his magic on the TWMX RM-Z motor. Tom’s always got a few new tricks up his sleeve, so we were eager to find out what he’d pull out of his hat by the end of the show. Starting with the top-end, Tom stripped the cylinder head and cleaned and ported it to his tested race specs. The crank was then lightened, balanced and cut while the cams were custom ground to specification. Heavy-duty cam followers were added, as well as heavy-duty titanium intake valves. A high-compression piston kit is used, and the carb is modified to suit the built motor. A heavy flywheel is optional, but we used it, and loved it! Hinson took care of the clutch woes via a billet basket, pressure plate and clutch cover, and heavy springs were added to help with slippage.

FMF took care of the exhaust system, bars and levers, while TCR laced up the wheels and added some finishing touches, resulting in ultra-trick rims and hubs. Works Connection dressed the bike with aluminum frame guards, motor guards and skid plate, and Dunlop hooked us up with some rubber.

Paul Thede at Race Tech suspension came next. Paul’s worked tightly all year with the racers on the Motoworld team, so he knows what’s up when it comes to modifying the stock KYB shock and forks that come standard on the RM-Z. Race Tech has done countless hours of computer and real-time testing on the RM-Z on both Supercross tracks, as well as a wide variety of outdoor tracks, so we had all the faith in the world. New springs and valving quickly took care of any of the complaints associated with the stock stuff. In all, you might say that Race Tech took care of the bumps for us…


From the very first kick of the bike, we could tell that this was going to be a fire breather. The compression was so strong that we had to really lay into it just to kick it over. Once started, the bike barked out an enormous and instantaneous snap of sound. The throaty, crisp response of the throttle had us eager to cut some laps out on the track. Talk about a quick revver! This bike revved so quickly and had so much bottom, it was almost a nightmare to ride. As soon as we got on the gas out of a turn, the bike begged to be shifted or it would fall flat (Note: we were at SoCal outdoor tracks that don’t always have the best traction.) The way this motor was delivered would be amazing on Supercross-style tracks or deep loamy tracks, but it was a struggle on the slick stuff. We quickly shot back to the pits, where Dave Dye applied a heavy flywheel-what a difference! The new flywheel allowed the bike to pull solidly throughout the entire powerband. Now, instead of short shifting the motor, we could let the bike rev all the way out. A strong, broad power curve had us ripping lap times similar to those we usually turned on the 450 machines. Although the stocker has good bottom and mid-range power, the TMR-modified motor flat-out blows it away. Good bottom, excellent mid and stellar over-rev was the end result.

Our only real complaint of the motor is with the difficult starting procedure. The high-compression motor makes it tough too kick, and if you don’t rub the rear fender, the right side of the gas tank and say the incantation “um, ba, ba, um, ba, ba, um” just right, the bike will take several monster stabs to fire.

With so much power under the hood, it was imperative for Race Tech to hook us up with the best of the best for suspension. In stock form, the KYB suspension on the RM-Z is not our favorite! It doesn’t completely suck, per se, but it just isn’t as good as the stock CRF or YZF units. The forks bottom easily, and have a harsh feel on deceleration. The shock has a very similar character, and acceleration bumps are also a problem. Race Tech starts by revalving the forks and the shock, and they change the spring rates around depending on rider weight and ability. A more progressive setting is applied, starting out a bit softer and ending considerably stronger. In other words, small bumps go almost unnoticed, while the big hits are handled with cushy ease.

So what’s the final result? Our top test rider jumped on the newly modified RM-Z at Glen Helen about a month before the first National was set to go off at Hangtown. As a result, a number of the top teams and riders were present. Once he got the bike started, he went out and ran lap times comparable to some of the top 125 racers in the country-for about four laps. What does this prove? It proves that with the TMR motor mods and the Race Tech suspension, this bike is every bit good enough to compete and run at the highest level. It also proves that our boy needs to start training a little harder! So if you’ve got a stock RM-Z250 that’s aching for some attention, we think you’ll be just as stoked as we are with the TMR/Race Tech combination…


Tom Morgan Racing

High compression piston kit $199

Shift pawl holder $135.95

Needle $21.95

Heavy duty spring kit $229.95

Ti intake valves $384

Heavy duty cam followers $389

Head porting $399

Carb mod $189

Flywheel mod $30

Crank mod $495

Cam mod $399

Flywheel weight $99.95

Race Tech

Rebuild Forks (Labor) $110

US1 Oil (2pt.) $ 24.98 each

Rebuild Shock (labor) $100.00

US1 Oil (1pt.) $24.98

FMGV 2840 Gold Valve $159.99

SMGV 4601 Gold Valve $159.99

Works connection

Skid plate $69.95

Frame guards $65.00

Engine guards $99.95

Front brake cap $24.95

Rear brake cap $22.00

Oil fill plug $22.00

Radiator braces $59.95

TCR Wheel Lacing

Exotic Racer Package $500 per set.

(Consists of wheel breakdown, stripping, polishing and anodizing. Turn down the hubs, and add exotic “mag” coating and rebuild)