Tale of Two Failed KLR650’s (Got an inspection hole?)

I always chuckle a bit when I hear stories on the Internet about the Kawasaki’s “bullet-
proof” KLR650. I have taken apart and studied more than 30 broken KLR engines in the 
past 17 years; most of them the victims of the poorly engineered balancer system or of 
faulty assembly at the factory. Pardon me if I’m a bit skeptical. In fact, if not for Sagebrush, 
Eagle, and the Wexman/Carl inspection port, I would have hung up my KLR spurs years 
ago. Thanks to Rod Morris at MMP and the beefy, new 2008 Kawasaki balancer 
adjustment lever, KLR650 engine reliability is about to take a big step forward, but more 
on that later. Let’s get on with the story.

About a year ago, Tore Bonanno was on the way south with some friends at San Quintin, 
Baja, Mexico, when his engine died – permanently. Inspection revealed that a large 
amount of coolant had entered the engine through a faulty oil seal behind the mechanical 
seal. The resultant witches brew of oil and coolant took its toll on bearings causing the 
engine to fail. The motorcycle, a 1988 KLR650 previously owned by the late Jake 
Jakeman, was purchased as salvage by Rod Morris. Jake, as you may remember, was the 
first person to come up with an improved, aftermarket balancer lever, among other 
products. Since Jake was so well-known in the KLR650 world, Rod is thinking of trying to 
resurrect the bike to original condition.

Now we turn to Jay Bass’ 2002 KLR650 with 37,000 miles on the clock. Not long ago we 
had helped Jay fix his broken subframe which had fractured after the right upper, 
aftermarket bolt had failed. Not long after, Jay’s bike was back on the road. He noticed the 
oil in the sight glass looked grayish. Since he had replaced the mechanical seal just 6 
months earlier, he was shocked that coolant had entered the engine through the oil seal – 
just like Mr. Bonanno’s bike.

Jay went to a mechanic in his hometown of Lemon Grove (near San Diego) and had the 
seal replaced again. A short time later, Jay’s bike stopped running about 25 miles from his 
home when the right-side 6204 bearing (behind the balancer and water pump) failed. The 
wobbly shaft damaged the oil seal again, allowing coolant to once more enter the engine. 
Result – one dead engine needing rebuild, including all new bearings in the crankcases.

There is a bright side to this story. When we pulled the rotor cover and rotor from the left
side of the engine, we found the aftermarket lever unbroken but the idler shaft had rotated
until the adjustment bolt was at the far (loosest) end of the adjustment slot. Further
inspection revealed that the aftermarket spring had broken. Since there was no
inspection port, the unsuspecting rider had loosened the adjustment bolt, allowing the
weight of the chain to take the lever to the loose end of the adjustment range. The
chain was so loose it was looping out and deflecting off the crankcase behind the left
cylinder stud.

Idler shaft rotated to loosest point  of adjustment possible.

Idler shaft rotated to loosest point
of adjustment possible.

Why is that the bright side to the story? Well, if the engine hadn’t died “quietly” due to the 
bearing failure, it would most likely suffered a more violent end when the balancer chain 
jumped track, stopped the engine, and locked the rear wheel. Ask Kurt Grife, Jim 
Bellach, Corby Hall, or any number of other KLR riders who’ve experienced sudden, 
catastrophic engine failure due to an excessively loose balancer chain.

Broken spring inside engine case.

Broken spring inside engine case.

Which brings us back to a balancer system failure with a happy ending, proving that the 
Wexman/Carl inspection port can really save your engine. Just ask our old friend Rod 
Morris. Rod has an aftermarket lever and spring installed in his 1996 KLR650. Prior to 
adjusting his balancer chain recently, he peered into his inspection hole. The spring 
was not in view! Rod did NOT loosen his balancer adjustment bolt, thereby avoiding a 
potentially dangerous situation. Rod is still riding, and will replace the spring with one of 
his new, improved balancer adjustment springs – discussed more below.

Screwdriver points to case  damage caused by loose balancer  chain.

Screwdriver points to case
damage caused by loose balancer
chain.

The springs are part of a balancer bullet-proofing kit Rod is developing which will 
include a new 2008 factory lever (call it “beefy” if you must), Wexman/Carl inspection 
port installation tool (very simple to use – Todd notes that even a Marine can do it!), 
two well-made extension springs, and an inexpensive otoscope to light up and magnify 
the spring during inspection. This same inspection hole and otoscope allowed Rod to 
notice his spring was missing. And once the spring is replaced, it will allow him to monitor 
the status of the balancer system, noting when the adjustment spring has reached coil 
bind and needs to be replaced with a shorter spring. Like Rod and Jay, I have had a 
broken adjustment spring as well, but like Rod, I didn’t lose my engine.

This lever was in good condition;  but the spring can still get you!

This lever was in good condition;
but the spring can still get you!

We had previously noted that there is a very similar extension spring INSIDE the DR650 
engine that works the shift pawl. We can’t imagine Suzuki using a failure-prone spring 
in a location that would require a complete engine tear-down to replace. 

Obviously, there must be some way to get a better spring. A long and determined search finally paid off. 
The spring manufacturer in question has a long history of making extension springs, 
earning their reputation making springs for dirt bike headers (a very hot and unfriendly 
environment for a spring) that wouldn’t break. They won’t give us all of their trade secrets, 
but they did tell us that the extension spring must be made with the intended working 
environment in mind. First of all, they will only use the best quality and type of wire for the 
job. They also emphasized proper design – particularly in avoiding any sharp bends in the 
spring. They stressed that a spring in this application needed to be strong but too much 
preload was probably not desirable. This is particularly interesting since we’ve pointed out 
the same concern in the past. The needle bearing on the idler shaft is relatively small and 
too much preload on the spring leads to more force on the bearing, increasing the chance 
of premature wear.  We are really looking forward to seeing the finished products.

Todd’s Note on Torsion Spring. As many of you know, there is a torsion spring offered
by the aftermarket to replace the factory extension spring. We would certainly like to hear
from riders who have installed these springs as the mileage on them accumulates. It may
turn out that this design is a successful alternative. We have several concerns about the
torsion spring. First, the torsion spring we purchased appears to be quite stiff, and
Kawasaki won’t tell us what the preload numbers should be with regard to the needle
bearing. Second, only with an extension spring can we monitor its preload and condition via
the inspection port.  Any spring has a chance of breaking, and we can’t see the torsion
spring. Even when Rod takes delivery of his new extension springs, and even though the
manufacturer has stated that “we’ll be astounded if you ever find one of our springs
broken,” we will still recommend installation of the inspection hole. The most dangerous
scenario regarding this balancer system is having a broken or missing spring, and
attempting to adjust the balancer chain. This will allow the system to go slack which will at
best result in a lot of metal-to-metal contact and noise and at worst, result in the chain
jumping off the sprocket resulting in a much-too-exciting end to your engine. Until we know
that the torsion spring exerts the proper pull and will not break, we’d rather use a high-
quality extension spring that we can monitor.