All our gears are ground after hardening process and meet closer tolerances than stock products. They are manfactured exclusively for us by a german gear manufacturer to HPN requirements. Highly sophisticated measuring equipment assures the high HPN Quality. For prices have a look at our pricelist.
HPN-1043ccm big bore kit
complete set - made in Germany (art.nr. 307)
Comes with: Cylinders with stainless steel pushrod tubing, pistons, head gasket, shortening of your cylinder bolts and pushrods, shortened intake manifolds, adaption of the squish area of your cylinder heads, TÜV certificate. Power output depending on the compression ratio and accessory from 48 kW (68 hp) to 53 kW (75 hp), weight saving compared to 980 ccm serial parts about 1,1kg, the piston is 182g lighter than the serial part. Engine width is reduced for 26mm.
HPN-titanium conrods
for the 2-valve-boxer (art.nr. 306)
Exclusively produced for HPN by a Formula 1 supplier for Ferrari. Wheight 350g (against 620g stock) complete with bearings for the sports engine.
HPN-gearings
long 5th - short 1st gear
Long fifth gear in picture left. Ratio change 5%+. Caution: Can be installed without changes in all BMW-GS bikes produced after 4/82 (due to 17,5° angle)*. Short first gear in picture right. Ratio change -5%. art.402
*Earlier models can be changed to this much more endurable gear type, as we also produce the intermediate shaft gear with the 17,5° angle. art.:403** In this case you need addionally the input shaft gear with 17,5° angle. art.403.1**
** Please order with motorcycle type and chassis nr.
HPN-rallye oil pan
with aluminum bottom plate (art.nr. 314)
Rallye oil pan with aluminum bottom plate avoids cracked oil pans when hitting ground or rocks. Race proofed item with a conical wheight reduced spacer ring.
HPN-oilcooler-thermostat
for a regulated temperature of your motor oil (art.nr. 302.1)
The thermostat is adjusted to begin opening at 90°C and is fully open at 110°C. This reduces the time to reach regular temperature and makes it possible to reach this temperature at all under bad weather conditions and in the cold season.
Caution ! There are often problems based on incorrect mounted parts when changing oilfilters. Engines of the GS series 87-96 need no paper gaskets under the filter cover. If the gasket is installed you can get severe motor damage due to low oil pressure and too high oil temperature. Please follow the mounting instructions - if you are not sure ask your dealer or HPN.