With the new bikes hitting the showroom floor we have had a full year to put the new KTM WP XPLR suspension through it’s paces. As the budget for suspension tightened up it is clear that we will see some shortcomings from the performance and modifications will be necessary for the serious rider or racer. Some issues to address will be the effectiveness of the fork compression adjustment and the long term durability of the shock.
WP XPLOR 48 Fork
With the 4CS a thing of the past we are on to a redesigned open chamber fork. Keeping with the single adjuster theme WP adjusts the XPLOR on the top with rebound and compression adjuster. Some models come with external pre-load adjusters. We have found the compression adjuster to make very little difference through out the range and the fork lacks sufficient dampening control for any aggressive riding. With most of the damping control isolated to the rebound side the compression side has a plunger style adjuster. This plunger valve body has an adjustable port area and an open cartridge via 4 holes just below the cartridge rod bushing. The plunger can never be totally closed off or else the fork would hydraulically lock out. This is a simple and not very effective design. The more parts they can leave out the lower the budget can be. Essentially just to get the bike off the showroom floor.
Total cartridge replacement. With high quality fork tubes replacing the lacking internals is a viable option. MX-TECH has designed and tuned a really nice complete cartridge fork that comes with necessary springs. LINK
Dal Soggio Sphere is another cartridge kit to replace the internals with high quality parts. Springs are additional. Some modifications are necessary for installation and it is recommended to have a professional install them.
DS also supplies an upgraded kit to add the missing parts called the XP-ONE.
Focused Fork revalve is available but added parts are recommended to gain added compression adjust-ability. Base valves and a 2nd mid-valve.
WP XPLOR SHOCK
WP goes for a lighter and less expensive design for the shock. Down to 46mm this shock is prone to overheating and fading with less shock fluid to control damping. The shock has a similar feel to the PDS as it has a tendency to have a fast rebound and kick up in consecutive bumps. The best solution for the shock is to revalve to correct the high speed damping for square edge bumps. Increased capacity by adding a TANK from MX-TECH. This will help keep the shock cool by lowering friction and adds overall oil capacity. The tank replaces the OEM plastic piston with a coated aluminium unit.
The second piston design has been simplified. Instead of the bottoming needle there is now a Ohlins or MX-TECH style piston and cylinder to aid in damping for the last part of the stroke. Along with the new piston there is a check valve.
If you have any questions or need to set up an appointment feel free to call us 661 252-0269.
Two weeks ago the N2Dirt crew prepped Sean Collier’s KTM 450SXF for the Race around the Lake GP. The track consisted of many different types of terrain to race on. From beach sand to concrete pathways and everything between. Getting a bike setup to go fast here is tricky to say the least. After spending all morning at LACR for the OTHG 9-11 memorial race, lead mechanic Brian Bolding hustled to Castaic lake for Pro race which was the last race of the day. Having raced the GP the day before Brian was able to make setting changes to Sean’s KTM to go from a MX setup to more of an offroad setting. The fast course was rough, hard, and dusty through most of the course. Sag adjustment, air pressure settings with the A48R, and clickers were all dialed in to suit the course.
Brian making last minute preparations on Sean’s KTM 450SXF.
Sean pulled an early lead over teammate Darryn Durham as the race started. After a few laps the lead was about 15 seconds as both riders found their pace over the rest of the pack. Sean’s bike was custom fitted with triple clamps and a Scott’s steering stabilizer by LuxonMX to keep Sean going fast and in control. As the rider’s searched for smooth lines the gap tighten. Darryn was pushing the pace and made up time on Sean. With super dusty and silty conditions making a move would be difficult as it was hard to see.
One of the less dusty spots on the course with the lake in the background.
As the race came to an end Sean and Darryn had left the rest of the field. Darryn made a late charge for the win but with out a whole lot of track left or room to pass Sean was able to cruise to victory.
Brian Medieros ripping the REM track.
Glen Helen REM Saturday MX returned from a month long summer break. With new bikes out the pits were super busy. The MXA crew switched brands all day long to get a feel for the new models. N2Dirt rider Tommy Wilcox came out and had an impressive day aboard his KTM with Brian wrenching for him. He ended the day with 4 moto wins including an overall even though he suffered a front flat.
Tommy making waves.
Jody Weisel of MXA testing out the N2Dirt suspension. These forks were fitted with the Sphere cartridges by Dal Soggio. He was impressed by the feel and it was a huge improvement over the stock fork.
Jon Ortner had a good day going 1-1 in the 50 elite class. The second moto he raced the KTM450sxf fitted with the Sphere system. It was a photo finished as the bike had a fuel leak at the end of the race from contact with another rider.
A heart felt tribute to an amazing man Tom White. The REM crew got together to give him this photo and banner. Tom is on the white flag lap in his life. As racers we all are like family to each other. Tom has been instrumental in so many ways to us and has made this world so much better. We honor and love the man you are. REM
Designed in collaboration with Luxon MX, N2dirt Suspension has created a high performance linkage to address the shortcomings of the 2015.5+ KTM/Husqvarna rear suspension.
These improvements include improved handling, wheel travel, and bottoming control.
The image below has wheel rate graphs vs stock positions to illustrate how our linkage can accomplish this by changing the rear suspension movement. The addition of this linkage is the first modification before any spring change or shim setting as they will need to be matched.
Click here to learn more
See the chart below to choose the proper spring rate for your bike.
Last weekend at the REM races, N2-Dirt’s Brian Bolding found five KTM 350SXF’s with loose crank nuts on the clutch side. This nut cannot fall off the end of the crank, but it can spin against the case, wear enough aluminum away to clog the oil lines and even allows the snap ring and crank seal to walk out. We recommend that you check the nut on the end of the your KTM 250 or 350 crank — it does require draining the water and removing the impeller to get to. The first signs are some strange engine noises, followed by the cam chain tensioner’s hydraulic lines getting clogged and eventually a ton of aluminum in your oil filter (you may have to cut the oil filter open to see it). We talked to KTM and expect a KTM dealer bulletin to be sent out. This only affects KTM 250SXF and 350SXF engines and not the 450SXF.
The 17.5 AER Fork received an update to the Air piston. We have found these to feel better with less friction after they are torn down and greased. The OEM grease is not sufficient and is grabby in the beginning of the range. We are updating all the older forks with this piston and the better grease. This is a great fork and a good design but needs some attention. Send us your fork and we can get you updated with the new piston and re-valve at the same time.
Read more here about the works mid-valve.