Fixin’ Rod’s Rods: Part 1

Rod Morris has two KLR650-A’s. One is an A-10 (1996) and the other an A-13 (1999). The 1996 was previously owned by Joe Carpenter, the best KLR dirt rider that Rod and I have ever ridden with. The 1999 was once the property of Mark Behling who built our first website which has since been shut down.

With 55,610 miles on the 1996 and 43,500 on the 1999 Rod decided it was time to rebuild both engines even though they were running well. It was also a good opportunity for me to show Ed Runnels all the tricks I had learned building KLR650 engines since my first one in the early 1990’s. Ed was already an accomplished mechanic so my training job ended after the first engine and I thus became an observer on the second. In fact, I inadvertently became a student of Ed’s on the second engine. Ed’s method of installing a forged C.P. piston into an “LA” cylinder sleeve is the best I’ve seen (thanks Ed).

Since completing a careful break-in of both engines Rod is positive that he has picked up some ponies. Stock KL-A’s produced 37.1 HP on the “Cycle World” dyno and the new E model (2008 – present) slightly less.

Rod reports that despite staying stock with bore/compression, and intake and exhaust system, both bikes run considerable stronger than before without sacrificing mileage or creating more air and noise pollution. Rod additionally claims oil use is close to nil thereby requiring oil and filter changes only.

Without telling you all our secrets I’ll give you a brief run down on some of the basic ingredients of Rod’s super KLR650 engines starting from the top down.

  •  The heads were carefully reconditioned and improved by long time master engine builder and race tuner, Vey de la Cruz. Work includes porting and texturing, valve job, and “Time-Serting” all four frail valve cover fastener holes.
  • Replace the ‘crappy warp prone” stock cylinder sleeve with L.A. Sleeve’s very special chrome moly cast iron cylinder sleeve.
  • Install MMP’s C.P. forged stock bore and stock compression piston which was developed by C.P. using my KLR head and cylinder a bunch of years ago (we believe the MMP/CP
  • forged piston was a first for the KLR650).
  • Vey trued both cranks as he always does and inspected the tranny assemblies. The A-10 looked like brand new, but the A-13 had a blown 3rd gear and some crank case damage which Vey repaired.
  • The balancer systems showed some significant wear, so we upgraded them with new front and rear balancer sprockets, idler shaft, idler shaft bearings, forged factory “E” model “doohickey” and MMP’s adjustable extension type doohickey springs, (inspection ports were installed years ago on both engines).
  • Since Rod runs his street KLR at higher sustained speeds (ask some of the sport bike guys on Hwy 94) than the dirt version we installed a front left balancer bearing that’s approximately 2 ½ times stronger than stock. Cruising all day at 5,500 RPM should be no problem. Additionally, the front balancer/water pump shaft can now be replaced without removing the outer bearing race.

The best part of Rod’s top end rebuild is that the stock bore, stock compression, lighter/stronger forged “C.P.” piston running in a non-warpable L.A. Sleeve provides the best possible compression in a cylinder that is handicapped by having only one spark plug in a 100mm hole. As Wood Racing, Vey de la Cruz, Suzuki, Rotax and many other reliable experts will tell you, two spark plugs “are the way to go” in large single cylinder engines. In short, to bore out a hole that is already too big for one spark plug makes no sense.

As the old saying goes, “keep it simple stupid”.

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