01.12.05 - The complete new XP 4 STROKE R minicross bikes are the racing versions of the famous XP 4 stroke minicross bikes produced by Polini. New equipment and new details are making them more precious. The most prestigious model is the one dedicate to the older lovers, equipped with High wheel, 14 front one and 12 rear one. New chassis and fork. Frame has new sizes to improve stability, weights distribution and handling. The same novelties have been made for the swing arm too. The second new model XP 4 STROKE R has the 14 front wheel and 12 rear one but the rims are in aluminium and no more in steel. The same for the big wheel bike.

XP 4 STROKE R: POLINI MINICROSS BIKES 4 STROKE FOR RACE
R; racing! Yes, here it is: the new minicross bikes with 4 stroke engine is at the cutting edge of the XP4 stroke series. Charming in its aesthetic and innovative at the same time. The technical solutions are very refined. The frame is new perfectly balanced; it is longer compared to the standard one, in order to improve stability. It is safer and it features performing details. It is perfectly balanced giving better handling. Improving stability and traction. The air cooled 4 stroke engine, 107cc, has 4 speed. The new XP4 T STROKE is a modern Pit minicross bike with a new design. Every single detail has been studied to satisfie the needs of all the riders. The new open single beam frame with lateral steel box-type stays and the trapezoidal swing arm, let you exploit to the utmost all the horse power. The main structure optimises the weight distribution, assuring great improvements, such as better with a longer fork to improve traction when setting the trajectory and gives more agility to the bike after the curve. It avoids tail jumping and loss of adhesion to the ground. The line is modern and elegant. It shows finishing touches of high level; shock-resistant and non-scratch light plastics of blue colour, metal paint grey frame with non-scratch adhesives. As always the most important features are of very high quality. The exhaust system is hand made with final silencer made of light alloy with oval section; it optimises the gas scavenging. The hydraulic disc brakes measure: 200mm front and 150mm rear. The hydraulic fork, with legs of d. 33 has been calibrated to work at the best on every ground, also for riders and adults who weight more than children. Legs and sleeves have been reinforced and the rear wheel excursion is of 175 mm. The steering tube is placed on cylindrical rollers bearings, and this is the best solution to grant stability on uneven ground. Rear single shock-absorber with specific setting. The handlebar is in light alloy with reinforced axle and buffers so that taller riders can drive it easier, and they have the possibility to maintain a natural position even in the narrower curves. The aluminium rims are assembled on light alloy hubs with straight spokes. The seat is covered by antiskid material. The big wheel model (front wheel 14/rear wheel 12) will have a great success all around the world. The model with front wheel 12/rear wheel 10 is particularly dedicated to the USA market which asks for this particular features.

POLINI 4 STROKE ENGINE
The single-cylindrical engine is air cooled with light alloy die-cast crankcase . The cylinder is in lamellar cast-iron. The head is a single-shaft model with two valves battery. The barrel is made of lamellar cast-iron too; it has a bore and stroke of 52,4 and 49,5. The displacement is 107 cc. It is air cooled. The multi-disc clutch has spring drives assembled on the primary speed shaft. The lubrication is in the wet crankcase. The 4 speed gear has straight teeth. The gear ratio is specific for the off road tracks and drive. The 22mm carburettor is by Mikuni. The air box is made of shockproof material. The sponge filter with open micro-cells can keep and filter every kind of matter.

NEW COMPLETE PRIMARY GEAR TRANSMISSION KIT FOR XP 4 STR. PIT BIKE ENGINES
For the most exigent 4str Pit Bike fans, Polini Motori presents a brand new primary transmission kit including: clutch case, complete clutch, shaft, transmission gears and cartridge oil filter. The light alloy - melted case has a compact design; its basic characteristics have been designed to improve lubrication. It distinguishes itself for the new oil way and filter cartridge: these are two solutions specifically oriented to optimize and improve lubrication. The advantages are tremendous: higher reliability and performances. The clutch kit is a product addressed to the real experts. The light alloy melded clutch bell, inner clutch and clutch puller have been produced in numerical check workshops. The disks have been lined with the last generation frictional material. The new Polini clutch includes: five clutch disks lined with frictional material, four C70 steel disks, flexible coupling made of high temperature resistant special rubber, clutch bell, clutch puller, inner coupling and primary sprocket. The primary transmission gear distinguishes itself for having ratios longer than the original ones. It makes the gear working conditions much better. It reduces the stresses, improving the power output and use.

POLINI TUNING CYLINDER KIT FOR HONDA XR 50 AND POLINI XP4 STROKE MINICROSS BIKES
Polini Motori has designed a new cylinder kit with bore 52,4 that can be fitted both on the Polini XP 4T minicross and motard bikes and on scooters and motorcycles equipped with the same 4 stroke engine made by different manufactures. This kit has really performing features. It includes cylinder, piston and head. Every single part has been studied by Polini's engineers to assure the best yield and optimises the power output at every rpm. The cylinder is in light alloy with nichel-silicium coating. It assures high resistance to heat and abrasion. If you assemble this cylinder kit 52mm bore on a minicross Honda XR 50, it increases the displacement to 90cc, while on a Polini minicross XP4 T it reaches 107cc. The piston is in aluminium die-cast at high silicon content. The head is made of aluminium alloy and gravity chilled and it has been designed using the new PRO/ENGINEERING three-dimensional system. It features a single-shaft distribution devise with 4 valves. It distinguishes itself for the smaller angle between the valves and for the burning chamber which is extremely small with the spark plugs placed in the centre and adequate to the squish, assuring great performance. It optimises the power output and reliability. The distribution diagram is the result of hard tests made in the Polini's workshop on state-of-the art electronic testing desks. The specific tests have let the engineers reach the best torque value without reducing the power output at the runway speed rate. All the working processes have been done using the most advanced production technologies. They assure a high quality level, maximum reliability and safety. The kit will be sold on the market in two versions: cylinder and piston or head kit only.