My Modifications

Springs, Grips, Pegs, Risers, etc.

Prior to purchasing the bike, I was given the opportunity to ride it for a day at our club's practice grounds.  Overall it worked well for me.  I knew a few simple changes would improve the bike for me substantially.  

The thing that bugged me most was the rear brake pedal – too far inboard and too high.  But that's not a problem unique to the EM, I had to extend the pedal tip 20mm outboard on my OSSAs too.

Next were the suspension springs.  The prior owner is a big guy and had installed stiffer springs at both ends.  Fortunately, that's an easy swap to return to standard.  There's only one spring in the front, and the rear does not require a spring compressor.  While things were apart, I took the opportunity to lube the suspension pivots and Anti-Sieze some fasteners.  I set the spring preloads at their minimums based on experience with other trials bikes.  I left the rebound clickers set at standard as that seemed a reasonable starting place for the initial testing.  After the next evaluation ride, I fully opened the “end of stroke” valve at the bottom of the left fork leg.  This took some of the harshness out of the last 25 mm of travel.  Unfortunately, I forgot to install the customary fork travel O-ring and ended up with a zip-tie.

The bike did not turn as well as I expected so I slid the fork tubes up in the triples about 6 mm.  This resulted in 10 mm being exposed above the top clamp.  The effect of all these changes left an already low skidplate with even less ground clearance.  In fact, the lean angle for the side stand was now quite precarious.  For me, the only real use for a side stand is moving bikes around in the garage, so I may eventually remove it completely.  I suppose some lighter suspension springs may be in the bike's future too.

Mostly for comfort, I installed my favorite Jitsie Grip footpegs.  These are wider and “grippier” than stock.  Likewise, the stock handgrips were swapped for softer and larger-diameter Progrip 699s.  These are streetbike grips that I use on everything (although not without modification on trials bikes).  Finally, I machined some homemade bar-end sliders out of acetyl plastic with retention hardware copied from Enduro Engineering's Bark Busters.  This helps ensure I won't scrape my hands on trees and the throttle won't stick open if I plant that bar-end in the dirt.

Most of my other trials bikes needed bar risers for comfort.  The ePure Race seemed comfortable without them, but Cindy convinced me to try them.  So I raised the bars 16 mm and do like it better.  Strangely, it also seemed to steer better – or at least more familiarly.

Unsurprisingly, the levers required some repositioning and adjustment to suit me.  I also removed the LED lights along with their DC-DC converter (which makes 12 volts out of battery voltage) and the associated wiring.  This simplified the wiring ever so slightly and removed that source of battery drain.

Coulomb Counter

I purchased a DROK coulomb counter via Amazon for about $31.  It is intended to give a real-time display of voltage, current, instantaneous power, and total watt-hours. 

But I don't care for it at all.  About the only good thing is that it has a Hall effect current transducer.  Thus, it was a simple matter to install this transducer on a battery cable by temporarily removing a pin from the Anderson connector.

DROK Coulomb Counter

The photo shows it being tested with the motor running while the bike is on a stand.  Despite remounting it in place of the OE Battery Capacity Indicator, it's nearly impossible for me to see the numbers change while riding.  I also detest its 2-button programming methodology – not intuitive at all.  And, even with the instructions in front of me, I can't get it to do what I expect.

There appears to be a slightly better 3-button version available via eBay (also for $31) but the characters are smaller and it ships from China. 

Fortunately, it's all moot as I have found an excellent solution available from Grin Technologies called the Cycle Analyst.  It is intended for electric bicycles.

2023 Modifications

Below is a summary of modifications made as I gained experience with the bike.   Most are discussed in detail elsewhere.

2024 Modifications

After much testing, I started the 2024 season with modifications that provided the best compromise performance.