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Sunday, July 31, 2011

Kawasaki ER6n-R ZX10R Front End Mod Part 1 - Fork Selection

Kawasaki ER6n a truly all round naked motorcycle which has tremendous potential. However built as an entry level budget motorcycle, it has numerous weak areas which can be improved with a few modifications. One of the weak spots is the front suspension which is built on an old school 41mm hydraulic telescopic fork. The telescopic fork is very basic without any pre load or damping adjustments options.
Improving the front end of the Er6 has been the challenge for many Er6n/f owners world wide and searching the Internet will easily uncover many adventurous individuals posting their modding efforts which is commonly revolving around utilizing the fork from the ZX6R or the 636.
I have choose to follow a path less ventured by using the front end parts from a few of the Er6n cousins which is the ZX10R.
My rational for this choice was made after extensive research from the Internet and discussion with the local track gurus. Decision was made after the following criteria were considered:
  • Mod options needs to be cost effective with minimum change to the components chosen.
  • Stock standard ZX6R / 636 forks were too soft and track going owners usually opted for stiffer springs soon after buying the sports bike.
  • Stock standard ZX6R / 636 forks (Kayaba) with a upper outer diameter (OD) of 50mm and a lower OD of 52mm and a length of 774.7mm is slightly longer then the base Er6 fork and will protrude too long above the upper triple when installed. This setup is fine if you are going with the Race clip-on type of handle bar (for the cafe racer look) but I however am looking to maintain the original stance of the Er6 with the Renthal type of handlebar.
  • The ZX10R fork which has a top triple OD of 50mm & lower OD of 54mm would be stiffer and looks beefier then the slimmer and longer ZX6R fork. There is a slight weight difference between the 2 forks (ZX10R weights a few grams heavier) but I did not feel the difference when riding. The slight weight difference would also act as a ballast to stabilize the vibration which the ER6n as a parallel twin is so notorious famous for.
  • The ZX6R fork is using a front wheel shaft that would need a 6005 sealed bearing with an internal diameter (ID) of 25mm 47mm(OD) would need extensive modification of the ER6n front wheel or a replacement with a complete ZX6R front wheel ($$). The ER6n wheel uses a 6004 bearing which has a ID of 20mm and an OD of 42mm similar to the specification of the ZX10R wheel from 2004-2005. This would mean that the fork from 2004-05 ZX10 you would just bolt on to a ER6n wheel without any modification.