Jörgs Motorcyle Pages: The birth of HPN 619


This page is dedicated to the transformation of my BMW R80GS into HPN 619.

On several occasions I had experienced that the fully loaded stock GS provides a "wobbly" riding experience on gravel and in deep sand, and I wanted to obtain a more stable chassis for quite a while. For a long time I had believed that it this effect could only be obtained through major changes in the chassis and the suspension ... until Klaus Pepperl — the "P" in HPN — explained to me that the mere reinforcement of the frame would already provide much more stability.

When Klaus added that this "basic frame reinforcement" is available for less than 800 € (HPN part number 03.102.10), I placed my order immediately.


Disassembly in 24 h

I received my frame number (0619) in 2015, but it took until summer 2017 until HPN was finally ready to receive my frame.

Within 24 hours after receipt of the shipping crate (fwiw: 115×40×62 cm), I completely disassembled the bike and sent the frame off to HPN in Seibersdorf, Germany.

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I proceeded roughly in the following sequence (cf. photos):

  1. Seat and gas tank
  2. Bash plates
  3. Side covers and their rubber supports
  4. Battery
  5. Footpegs
  6. Luggage system
  7. Muffler
  8. Rear mudguard
  9. Battery holder and 12-V plug
  10. Rear subframe. Note that the right-side passenger footpeg has an "almost inaccessible" bolt
  11. Crashbars
  12. Alternator
  13. Remainder of exhaust system
  14. Airbox and carburetors
  15. Rear shock
  16. Rear swingarm
  17. Gearbox
  18. Main wiring harness
  19. Engine
  20. Instruments and cockpit
  21. Signal horn
  22. Handlebar wiring harness
  23. Front wheel
  24. Front fork
  25. Steering head lock

During the whole process, I took lots of photos. Knowing that a few weeks would pass until I could reassemble the bike, it was important to me to document in particular the placement of non-stock parts such as the luggage system, but also the placement of cables, bolts and washers. Obviously, not all photos are shown here.

I used cardboard boxes and lots of transparent bags to store the parts. I found that punched pockets in A4 size were very handy: big enough to hold parts ranging from bolts up to footpegs and mirrors, yet transparent and flexible.

It is important to remove all tiny bits and pieces from the frame. This includes in particular the steering lock, but also all rubber elements from the frame, subframe, centerstand, luggage system, bash plate and many other places.

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While the frame was with HPN, I performed exhaustive maintenance, such as:

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Only five weeks later, the reinforced frame was back in my garage. At least two of these five weeks were lost through customs clearance and postal services, but this was expected.

My idea was to use HPN's basic frame reinforcement and still keep the rest of the bike close to the factory settings, being able to use as many factory parts as possible. My order included a few particular items that I do not need right now but that would be difficult to add later on:

In addition, I specified that I wanted to continue to use the original seat, original side covers and the Hepco luggage holders. All points were fully respected.

Here's the unboxing and a first look at the "new" frame:

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Reassembly was performed deliberately slowly, over a period of two weeks and testing almost every part. I proceeded roughly in the following sequence:

  1. Rubber parts to centerstand
  2. Centerstand to frame
  3. Steering lock
  4. Rear brake lever and brake switch, including attachment of cable "behind" frame
  5. Paralever rod
  6. Final drive and rear shock
  7. Rear brake
  8. Rear wheel
  9. Front fork
  10. Front wheel
  11. Engine
  12. Gearbox — do not forget the central rod that activates the clutch!
  13. Lower part of air filter box
  14. Connect driveshaft
  15. Wiring harness for oil pressure and gearbox
  16. Battery holder
  17. Main wiring harness (bring into position but do not attach yet. I also replaced all the broken tubing of the wires of the front turn signals).
  18. Ignition module
  19. Alternator regulator
  20. Relays (3×)
  21. Horn
  22. "Mudguard" in front of ignition coil
  23. Ignition coil
  24. Engine top cover
  25. Clutch cable
  26. Footpegs rider
  27. Instrument cluster (insert the little cable for the tachometer early)
  28. Speedometer with cable
  29. Headlight
  30. Front turn signals
  31. Handlebar
  32. Handlebar cabling (I needed to invert the places of the white and red connectors)
  33. Carburetors
  34. Air filter
  35. Exhaust downpipes and collector
  36. Rear subframe
  37. Rear mudguard with taillight and turn signals
  38. Muffler
  39. Passenger footpeg R (you may want to change the hex bolt against inbus and you may need to remove the rear wheel again)
  40. Pannier racks and passenger footpeg L
  41. Battery
  42. Vent line for gas tank
  43. Gas tank (rework needed for the tubular semi-brace, see below)
  44. Seat
  45. Bash plates

The HPN-typical frame modifications are the source of a few modifications that you will need to take into account:

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The first ride

On 2017-08-20, HPN 619 hit the road for the first time.

I was curious to see and to ride ("er-fahren") the difference. All HPN that I had ridden before were custom-made bikes, all with different suspension elements, longer suspension travel and usually also with a different frame geometry. Those were all impressive bikes, but I always missed something that would allow me to assess the influence of a given component alone.

The first time this became possible for me was now, on my own bike. HPN had only added the standard frame reinforcement and changed the steering head bearing. Everything else was identical: this was the stock fork with WP springs (now with fresh oil), the rear stock was the same Öhlins (not even revised), geometry and suspension travel were both unchanged. Essentially, all parts were the same, just cleaner ;-)

I now have a new, different bike.

Near my place I have a few bends and corners at hand where I know that the GS would start to feel instable — never really disturbing but enough to become noticeable — which means that I would keep the right hand under control. Riding through these same bends on the HPN, there is ... nothing. No movement, no insecurity. Just a big grin in my face. I even caught myself taking some of these bends much faster than I usually do.

Speed wobble is totally absent. On the stock GS, I could eventually generate 2-3 oscillations (with rapidly decreasing amplitude) by hitting the handlebar. On the HPN, the handlebar immediately returns to its zero position.

"Must Have"

In conclusion: I did not have expect that "only" the frame reinforcement would have such a noticeable, positive impact. I am more than satisfied. This is a must have. And yes, I am grinning extra large as I am writing this :-)

If you want to make the GS an even better bike, start with the HPN frame. And no, I am not one of their shareholders.