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Early USA Model '85 K100RT Rendition Thu Apr 04, 2013 9:16 pm
AJ.Valente
Life time member
Background: Two models of 2-valve K100s were imported to the USA in 1985; the RS and RT, mechanically the same except for rear end ratios and weight differences of 10 lbs. The RS "road sport" model became the more popular of the two and about twice as many were produced. The RT was the top-of-the-line "road touring" model that featured full faring and mid-height handlebars.
Early US models are distinguished by the clean rear clip, and the bike featured here (prod# 0052864) had its rims painted to match by the original owner. This machine (below) had been well maintained including all required warranty work with dealer servicing stickers extending to 46,000 miles.*
Both RS and RT models feature windscreen air foils requiring full-face helmet for proper operation.** The RT faring extended down lower to cover the rider's legs as well as rising up higher to match the handlebars. Remarkably, this configuration fairly obscures the tank roundels, which are the originals shown here. On this bike the lower farings are replaced with the '89 style with air foils to redirect air past side vents to improve engine cooling.
Back in 1985 it would have been outrageous to fit an RT with race tires, but over the past 25 years tire technology has advanced significantly. This rendition will ride on new bias ply Bridgestones using the RS configuration--a V-rated BT-45 110/90 front and H-rated S-11 130/90 rear.*** The BT-45 "Battlax" is a dual compound rubber with hard center and soft sidewalls. Due to its rounded profile the bike seems lighter, is easier to tilt, and has vastly improved low speed handling characteristics. The sports-touring S-11 "Spitfire" is also a duo-compound tire that combines excellent handling with a tread pattern designed to shed rain water. **** Wind blast on the full faring is the one knock against the RT, but these tires make recovery that much easier. 
(above: Original under seat sticker with tire recommendations from 1985)
Here in upstate New Hampshire about 100 mi. from the Canadian border the bike resides in the "barn" during winter while necessary maintenance and upgrades are performed (see links below). In early spring it's rolled-out sans' panniers and engine safety bars saving about 10 lbs. Rubber plugs are fitted to holes in the lower fairings where safety bars normally pass and it's ridden this way for about 2-weeks while everything is checked-out.
to be continued . .
* Purchased by current owner with 56k mi. and currently has 62k mi. on the clock.
** Riding with an open face helmet on the RT at freeway speeds requires the rider to constantly duck down under the windscreen due to excessive wind and noise. But, a full-face helmet relieves this problem and creates a perfect bubble of air all around it. I ride with the G-Max GX68 that has 9 separate air vents and is very quiet at speed, it's a great combination with the '85 RT.
*** Last year the bike had V-rated Metzlers on front and rear (100/90 and 130/80 respectfully). It has been written that 110/90 on the front can be unstable in tight cornering, and this seems true of the Metzler as the heavily ribbed pattern seems to resist rolling. The Bridgestone pattern is much smoother and readily invites rolling into curves. A review of the Bridgestone Battlax on K-bikes said it was not good at high speed cornering, however Bridgestone doesn't make a Battlax rear tire of 130/80 so the report is not clear on this important point. At any rate, we're using the H-rated Bridgestone Spitfire on the rear, and its cornering characteristics are excellent. The speed rating of H-rated tires is still 130 MPH, so it's not like we're loosing any performance.
Winter upgrades on this bike:
1) LEDs in guages; https://www.k100-forum.com/t223-led-lights-in-the-instrument-pod-plus-sealing-out-the-moisture
2) Compartment lid lanyards; https://www.k100-forum.com/t5472-compartment-lid-lanyards
Last edited by AJ.Valente on Thu Mar 13, 2014 10:14 am; edited 3 times in total
