Stroker's KLX-365 Kit

I like having something unique. The YZ-400 is a killer machine but everyone and their dog has one.  The Cannondale might NEVER make it to market, the other, more exotic European thumpers are now subject to ridiculous taxation, and none of the other major manufacturers are ready to release a competitive thumper.  I decided to keep Kenny and let Stroker work their magic on the motor.  An RMD buddy told me that Stroker could install a KLX-300 cylinder and head with slight modifications for the cooling system and then bore and stroke it to a 365cc beast.

I called Stroker and spoke for quite a while with Dave Bombard.  I have to give Stroker credit.  They take the time to explain every detail and they're not pushy sales types.  After a few rounds of discussions, I figured, what the hell.  It's only money, right?  Kenny was stripped to the bone and underwent major reconstructive surgery.  His frame was sent to a welder for strategic reinforcement in the steering tube, linkage and swingarm mounts, and the rear shock's upper mount.  He made it through that procedure like a trooper and was rewarded with a sandblast job and a killer KX green powder coat.  I boxed the motor up in a plastic Igloo cooler and shipped it to Stroker for Dave to do his thing on it.

I opted for the full 365 "Stage III" package. This included the KLX-300 Head and cylinder, 83mm Bore, Stroked Crank, Race Cams and Timing, Stainless Valves, Breather Kit, Manual Compression Release, Beefed-Up Clutch, Idler Gear, Keyless Remote Entry, 3-D Virtual Reality Helmet, and the Time Travel option.  I knew I needed a race carburetor to really recognize the motor's potential.  Stroker gets $500 for their Keihin 35mm FCR racing carb. You can find this carb around the net for $325 to $350, but there's a catch.  Stroker has custom enngineered this carburetor to meet their specs.  If you seek an alternate source, be prepeared to make some changes. I listed these changes below in the carburetor section.

Stroker did a bang up job on the motor. They had it in their shop for only one week and it was back out the door to me.  Here's some old parts that came back.  Stroker sends quite a bit of documentation back with the motors.  In fact, they ship the installation documents for every feature they install. I thought it was cool to get back the old parts too.  HEY!  I'll make someone a great deal on a KLX-250 head, piston, and other assorted parts. ;)   My little "submarine mission" in the Red River last year had apparantly done an internal number on the motor. I could feel something wrong over the past few months and I knew I was in for trouble. Dave at Stroker commented that there was all sorts of debris in the cases. Bearings were eaten up and parts severely damaged.  My idler gear was almost toast. Dave estimated that I had maybe ten kicks left on the kickstarter. Good thing that last race was canceled!  Otherwise, I'd probably still be out there looking for motor parts.

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Kenny's KLX Carcas - Disassembly was easy - hope reassembly is! The "new" motor looks like the old motor, but looks are deceiving! Parts are parts...and these parts ain't cheap! Stroker's manual compression release arm. Don't do the 365 kit without it


Right Side Steering Tube Reinforcement- 1/8" Steel Plate Left Side Steering Tube Reinforcement - 1/8" Steel Plate Too bad it won't look this nice forever!


This is the FCR 35mm pumper carb Stroker recommends. Notice the push-pull throttle cable mount at the top right. The push cable is not used on the KLX-365 and the mount has to be cut so the carb will fit against the engine valve cover. Stroker recommends a 168 main, 48 pilot, and a Yamaha OBDVR needle at the 4th clip position. Look closely at the lightened section of this image. This is the installed FCR carb with the push-pull cable mount cut away as needed.


S-l-o-w progress...  I removed the front light, rear lighted fender, and replaced the white side panels with black ones.

Firing Kenny up for the first time was a real rush.  Stroker recommended a starting procedure that will take some getting used to but it works. The 11.5:1 compression ratio is massive compared to the 250 motor.  I can stand with all my weight and the kick starter will not budge.  The manual compression release is a real life (and knee) saver here.  After about a dozen kicks, the motor roared to life with massive, involuntary bowel movement-inducing thump.  Here's a pic of Kenny today.  This is one bad looking mother thumper of a bike...if I do say so myself!  All I need now is a wheelie bar and a roll cage!

Click for Larger Image

I've had the opportunity to break in the new motor.  I can't describe how tedious it was going through the break-in cycle.  The natural urge is to jump on the throttle and see what happens.  But for the money and time I put into the project, I figured I should follow the conventional wisdom and take the necessary precautions.

Finally, the bike was ready, the weather was great, and I actually had time to ride.  I decided to go to Muenster and kill two birds with one stone.  Our club, the Red River Dirt Riders is hosting an enduro on October 31st and I needed to work on my section.

Starting the 365 is a bit different than it was with the 250.  Use the compression release or kiss your knee good bye.  The Keihin FCR carb has no manual choke.  Two or three kicks with the compression release engaged followed by a  kick from just past top dead center without the release and kaboom. No throttle is necessary.  While the difference in power from the 250 is tremendous, it's still manageable and fun to ride.  The gearing is the same so there were no surprises there.  What I did notice is how quickly the bike accelerates.  Initially, when  the motor revved high, it would start sputtering.  I thought I might be lean in the main jetting until I realized how fast I was going.  "Shift, stupid!"  Stroker told me that the shifting would be different but I never thought I'd have to run through the gears so fast.  Riding in the creek beds at Muenster gave me the opportunity to really open it up that I rarely get in an enduro or on an MX track.  I was in 6th gear before I knew it and the scenery was a blur.  It was great!  I can climb the side of my house with the torque from this motor.  I'll definitely need to adjust the high speed circuit on my Scott's Steering Stabilizer.

One thing I noticed at Muenster was that the Keihin FCR carb's accelerator pump linkage is susceptible to exposure.  At one point in the day, I found myself knee deep in the thickest puddling-like slop I've ever seen.  It was an innocent mistake but that's another story.  The bottom line is that the muck and grime in the creek beds coated the pumper linkage and even got under the rubber boot and into the pump reservoir.  This made starting in the mud a bitch.  The linkage is easily cleaned when the bowl is removed.  Removing the bowl is surprisingly easy given that the KLX appears to be designed around a carburetor that was half the size of the FCR.  Still, I need to figure out a way to shield the accelerator pump linkage while still giving it a free range of movement.

The clutch pull is very tight.  Granted, the 250 springs were four years old and were Kawasaki stock.  The Stroker replacements are heavy duty and I noticed the additional resistance instantly. It's not stiff to the point of getting in the way, but it's certainly worth noting. I also noticed how quickly the motor revved out. My final drive ratio was 14:51.  I found out that Stroker recommends a 15:46 ratio!  No wonder I could wheelie in 6th gear!  I installed a 15-tooth sprocket up front which helped a great deal. There's still more than enough torque on bottom, but I can reach much higher top speeds without worrying about blowing up the new motor.   I'll change out the rear sprocket when I replace the tire, fix a flat, or some other rear wheel maintenance.

All in all, I'm very pleased with the bike.  I'm sure there will be some additional tweaking here and there but so far, it's great.  I highly recommend the Stroker package if you're finding the KLX-250 or 300 lacking power.  My son has a '99 KLX-300 with a 36mm Mikuni pumper carb, Stroker/Pro Circuit exhaust, and all the breathing enhancements.  Even with these mods, the KLX-300 is just no match for the Strokerized 365.  And it's more than just a 65cc displacement difference.  It's a difference you have to feel for yourself.

If you plan on going the Stroker motor build route, be prepared to spend a few bucks to get it all done.  I won't go into detail on my costs because every bike will be different. Maybe I went over the edge with this one, but's only money, right?