2007 Suzuki RM-Z250 - Long Haul - Wrap Up - Dirt Rider Magazine

As of the last update on our Long Haul RM-Z250 (October '07), the bike was scoring particularly high on the fun meter but was in need of a good "freshen" session in the shop. As soon as the hourmeter rolled 50, we took the Suzuki to Dave Dye's Total Performance race shop in Hesperia, California. Digging into the motor, Dye found that the piston was looking pretty good but the cylinder showed some areas where the cross-hatching was worn smooth. As a result, he chose to put in a new cylinder to hold the new piston and rings. A small chunk of a clutch plate that had broken earlier in the bike's life had gotten into the channel for the cam bearing; that small piece of debris prevented the cam from sitting straight, which caused wear on the cam and the head. Dye built and installed a new head. In order to cure the shifting bugs, Dye also threw in a shift stopper spring off of a 2008 RM-Z250, which he claimed would make the bike shift much more smoothly and with less jumping out of gear. A thorough check of the rest of the bike revealed some blown-out silencer packing and a badly stripped oil drain plug bolt, both of which were fixed before the machine was handed back race-ready.After a new set of One Industries graphics, a Sunline handlebar and Moto Ray hand guards, the RM-Z was served 14 hours of hard motoing. From practice track days to local races and even a few post-rain rides in the hills, the bike performed excellently no matter what the conditions held. With the jetting still clean and the power holding strong, our biggest complaint sat with the Elka suspension, which had broken in to a stiff, harsh point that seemed to fight most pilots on rough tracks. While many of our pro testers still liked the setup, the jury called for the suspension to be revamped. Thus, we again shipped both the fork and shock to Canada and were much happier with the end result. Aiming for a WORCS-style setup, Elka refreshed and revalved the suspension and set up the RM-Z so that it now rode far smoother in the stroke, with increased settling in the turns to keep things sharp.It was at this time that we began to receive some of the '08 250Fs for testing, which meant that the staff would soon be neck-deep in first impressions with little extra time to devote to the Long Haul bike. Luckily, most of our expert testers ride every day of the week and are more than happy to bank hours on the Long Haul fleet. Privateer hero Chris Barrett mentioned that he'd like to borrow a 250F to practice on, so we handed over the RM-Z along with a stack of tires, filters and a case of Amsoil oil. Here's what he had to say:"With 64 hours on the RM-Z250, I was surprised at how strong the motor felt. The bike ripped! I was also impressed with the Boyesen Supercooler, as I didn't have any problems with overheating the smaller-than-I'm-used-to motor. The newly refurbished Elka suspension still worked like a champ and the whole bike felt really tight overall. Usually when you get to around 55-plus hours on a bike, it starts to feel pretty clapped out-not so for the Suzuki: If you keep up on regular maintenance and don't abuse the rev-limiter, she'll keep running strong for as long as you need."I rode the 250F on my usual rotation of local practice tracks and was impressed with how fun the bike was to moto. Even though I race 450s in Supercross and outdoors, the smaller motor on the Suzuki reminded me to carry speed into corners and keep my momentum up around the track. After two sets of tires on each end, three well-used Ready Racing air filters, four bottles of Amsoil oil and two oil filters, I gave the RM-Z back at 86 hours. Even with all the riding, the Suzuki never lost much power and still handled like new."

From here, we took the well-used machine out for two more solid rides to determine the toll that the hours had taken. Compared to when we had given Barrett the bike more than 20 hours prior, the motor had lost relatively little power, but the engine noise was noticeably up and the clutch was completely toast. Moreover, the all-too-familiar transmission goblins were still causing the Suzuki to skip out of gear on increasingly frequent occasions. After a final ride and a thorough washing, we rolled the RM-Z into the shop for the last time for its concluding teardown.Seeing as the bike continued to feel great on the track, we decided to only do a motor teardown on the RM-Z, since the chassis and components were still in good shape. Ripping into the Suzuki's engine, we found a piston that looked fine but was ready for replacement. The cylinder showed the same shiny spots, but Dye had enough experience with the new engine to state that it wasn't a sign of damage, rather it was typical for the model. We used the same cylinder to reassemble the engine, although splitting the cases and removing the crankshaft proved to be a bigger challenge; you need to use a press. Our experience told us it was time for a new crank, so we replaced that as well. Upon reassembly it started on the first kick and sounded strong.Overall, this Suzuki shows what can be expected from a 250F used at a high level. You simply have to take care of it. Left mostly stock, the Suzuki remained reliable all season long thanks to regular maintenance and a responsible testing crew. Although the '07 RM-Z has left the Dirt Rider stable, we have no doubt that this bike has many more seasons of good riding left in it.Running Tally
Hours Since Last Update: 40.3
Hours on Bike: 87.3
Modifications: $2145.16
Elka Suspension modifications: $429.90 (fork revalve and labor, $195; fork oil, $19.95; shock revalve, $195; shock oil, $19.95)
One Industries Technoflex graphics: $134.90
Sunline double-diamond medium-compound grip kit: $16.95
Sunline Moto Ray hand guards: $69.95
2008 shift stopper spring: $2.26
Nuetech APE Attack bend bar ends: $99.95
Maintenance and Repairs (not including tires): $1626.87
Two piston kits: $242.70 ($121.35 ea. for piston, wrist pin, circlips and rings)
Two gasket sets: $170.54 ($85.27 ea.)
Cylinder: $424.39
Crank: $407.27
Front wheel bearings: $28.34
New head: $470.15
Intake cam: $214.70
Exhaust cam: $241.63
Sunline AVOne OSX handlebar kit: $129.95
9 bottles Amsoil 10W-40 oil: $80.55 ($8.95 ea.)
4 Michelin rear tires (1 S12 and 3 M12): $389 (S12, $95 ea.; M12, $98 ea.)
3 Michelin M12 front tires: $264 ($88 ea.)
7 Ready Racing air filters: $69.65 ($9.95 ea.)
2 Ready Racing stainless oil filters: $99.90 ($49.95 ea.)