|We are tuning in
close discussion with our customers and if necessary
fulfil the street legality requirements of the german or
even swiss homologation. From the slim racing engine over
the power encreasing engine overhaul to our showpeace,
the HPN-boxer-engine with 75hp at 1043ccm goes the range
of tuning. If necessary in a HPN
or BMW street bike the engine in combination with the HPN
Baja muffler fulfills the 80db noise and ECE pollution
requirements.The tuning is not limited to the Mahle-cylinders and pistons,
a lot of work is spent for details like
sports-crankshaft, titanium conrods,
special camshaft for more midrange torque and top power,
head porting, double ignition, and exact definition of
the compression ratio for the required use. We take the
same care for your engine in case of an overhaul or
repair. Of course we use modern machinery for valve seat
machining. A lot of motorcycle magazines stated the
vibrationless running of the HPN
tuned engines and measured power.We tune the transmission and clutch of
your bike as well. The clutch gets adapted with a
reinforced friction plate and more pressure to the higher
torque and bad running conditions in deep sand and a lot
of dust. The transmission can get additional magnetos to
hold back tiny steel particels; art.: 401.5 (without
picture). With different gear ratios we adapt your
transmission to your ideas. First gear can get a short
ratio for trial passages, for touring riding we give you
a long fifth gear to lower revs. and fuel consumption. We
take care of your faulty transmission and modify older
transmissions to the latest specs. Corroded gear boxes
become like new after glass blasting treatment.
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
|1043 ccm 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.
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.
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
|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.
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.
(top) (HPN-starting point)